/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.documentsui.dirlist;
import static com.android.documentsui.Shared.DEBUG;
import static com.android.documentsui.dirlist.ModelBackedDocumentsAdapter.ITEM_TYPE_DIRECTORY;
import static com.android.documentsui.dirlist.ModelBackedDocumentsAdapter.ITEM_TYPE_DOCUMENT;
import android.annotation.IntDef;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.annotation.Nullable;
import android.support.annotation.VisibleForTesting;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.util.SparseArray;
import android.util.SparseBooleanArray;
import android.util.SparseIntArray;
import android.view.MotionEvent;
import android.view.View;
import com.android.documentsui.Events.InputEvent;
import com.android.documentsui.Events.MotionInputEvent;
import com.android.documentsui.R;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* MultiSelectManager provides support traditional multi-item selection support to RecyclerView.
* Additionally it can be configured to restrict selection to a single element, @see
* #setSelectMode.
*/
public final class MultiSelectManager {
@IntDef(flag = true, value = {
MODE_MULTIPLE,
MODE_SINGLE
})
@Retention(RetentionPolicy.SOURCE)
public @interface SelectionMode {}
public static final int MODE_MULTIPLE = 0;
public static final int MODE_SINGLE = 1;
private static final String TAG = "MultiSelectManager";
private final Selection mSelection = new Selection();
private final SelectionEnvironment mEnvironment;
private final DocumentsAdapter mAdapter;
private final List<MultiSelectManager.Callback> mCallbacks = new ArrayList<>(1);
private Range mRanger;
private boolean mSingleSelect;
@Nullable private BandController mBandManager;
/**
* @param mode Selection single or multiple selection mode.
* @param initialSelection selection state probably preserved in external state.
*/
public MultiSelectManager(
final RecyclerView recyclerView,
DocumentsAdapter adapter,
@SelectionMode int mode,
@Nullable Selection initialSelection) {
this(new RuntimeSelectionEnvironment(recyclerView), adapter, mode, initialSelection);
if (mode == MODE_MULTIPLE) {
// TODO: Don't load this on low memory devices.
mBandManager = new BandController();
}
recyclerView.addOnItemTouchListener(
new RecyclerView.OnItemTouchListener() {
@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
if (mBandManager != null) {
return mBandManager.handleEvent(new MotionInputEvent(e, recyclerView));
}
return false;
}
@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
mBandManager.processInputEvent(
new MotionInputEvent(e, recyclerView));
}
@Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {}
});
}
/**
* Constructs a new instance with {@code adapter} and {@code helper}.
* @param runtimeSelectionEnvironment
* @hide
*/
@VisibleForTesting
MultiSelectManager(
SelectionEnvironment environment,
DocumentsAdapter adapter,
@SelectionMode int mode,
@Nullable Selection initialSelection) {
assert(environment != null);
assert(adapter != null);
mEnvironment = environment;
mAdapter = adapter;
mSingleSelect = mode == MODE_SINGLE;
if (initialSelection != null) {
mSelection.copyFrom(initialSelection);
}
mAdapter.registerAdapterDataObserver(
new RecyclerView.AdapterDataObserver() {
private List<String> mModelIds;
@Override
public void onChanged() {
mModelIds = mAdapter.getModelIds();
// Update the selection to remove any disappeared IDs.
mSelection.cancelProvisionalSelection();
mSelection.intersect(mModelIds);
if (mBandManager != null && mBandManager.isActive()) {
mBandManager.endBandSelect();
}
}
@Override
public void onItemRangeChanged(
int startPosition, int itemCount, Object payload) {
// No change in position. Ignoring.
}
@Override
public void onItemRangeInserted(int startPosition, int itemCount) {
mSelection.cancelProvisionalSelection();
}
@Override
public void onItemRangeRemoved(int startPosition, int itemCount) {
assert(startPosition >= 0);
assert(itemCount > 0);
mSelection.cancelProvisionalSelection();
// Remove any disappeared IDs from the selection.
mSelection.intersect(mModelIds);
}
@Override
public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
throw new UnsupportedOperationException();
}
});
}
/**
* Adds {@code callback} such that it will be notified when {@code MultiSelectManager}
* events occur.
*
* @param callback
*/
public void addCallback(MultiSelectManager.Callback callback) {
mCallbacks.add(callback);
}
public boolean hasSelection() {
return !mSelection.isEmpty();
}
/**
* Returns a Selection object that provides a live view
* on the current selection.
*
* @see #getSelection(Selection) on how to get a snapshot
* of the selection that will not reflect future changes
* to selection.
*
* @return The current selection.
*/
public Selection getSelection() {
return mSelection;
}
/**
* Updates {@code dest} to reflect the current selection.
* @param dest
*
* @return The Selection instance passed in, for convenience.
*/
public Selection getSelection(Selection dest) {
dest.copyFrom(mSelection);
return dest;
}
/**
* Updates selection to include items in {@code selection}.
*/
public void updateSelection(Selection selection) {
setItemsSelected(selection.toList(), true);
}
/**
* Sets the selected state of the specified items. Note that the callback will NOT
* be consulted to see if an item can be selected.
*
* @param ids
* @param selected
* @return
*/
public boolean setItemsSelected(Iterable<String> ids, boolean selected) {
boolean changed = false;
for (String id: ids) {
boolean itemChanged = selected ? mSelection.add(id) : mSelection.remove(id);
if (itemChanged) {
notifyItemStateChanged(id, selected);
}
changed |= itemChanged;
}
notifySelectionChanged();
return changed;
}
/**
* Clears the selection and notifies (even if nothing changes).
*/
public void clearSelection() {
clearSelectionQuietly();
notifySelectionChanged();
}
public void handleLayoutChanged() {
if (mBandManager != null) {
mBandManager.handleLayoutChanged();
}
}
/**
* Clears the selection, without notifying selection listeners. UI elements still need to be
* notified about state changes so that they can update their appearance.
*/
private void clearSelectionQuietly() {
mRanger = null;
if (!hasSelection()) {
return;
}
Selection oldSelection = getSelection(new Selection());
mSelection.clear();
for (String id: oldSelection.getAll()) {
notifyItemStateChanged(id, false);
}
}
@VisibleForTesting
void onLongPress(InputEvent input) {
if (DEBUG) Log.d(TAG, "Handling long press event.");
if (!input.isOverItem()) {
if (DEBUG) Log.i(TAG, "Cannot handle tap. No adapter position available.");
}
handleAdapterEvent(input);
}
@VisibleForTesting
boolean onSingleTapUp(InputEvent input) {
if (DEBUG) Log.d(TAG, "Processing tap event.");
if (!hasSelection()) {
// No selection active - do nothing.
return false;
}
if (!input.isOverItem()) {
if (DEBUG) Log.d(TAG, "Activity has no position. Canceling selection.");
clearSelection();
return false;
}
handleAdapterEvent(input);
return true;
}
/**
* Handles a change caused by a click on the item with the given position. If the Shift key is
* held down, this performs a range select; otherwise, it simply toggles the item's selection
* state.
*/
private void handleAdapterEvent(InputEvent input) {
if (mRanger != null && input.isShiftKeyDown()) {
mRanger.snapSelection(input.getItemPosition());
// We're being lazy here notifying even when something might not have changed.
// To make this more correct, we'd need to update the Ranger class to return
// information about what has changed.
notifySelectionChanged();
} else {
int position = input.getItemPosition();
toggleSelection(position);
setSelectionRangeBegin(position);
}
}
/**
* A convenience method for toggling selection by adapter position.
*
* @param position Adapter position to toggle.
*/
private void toggleSelection(int position) {
// Position may be special "no position" during certain
// transitional phases. If so, skip handling of the event.
if (position == RecyclerView.NO_POSITION) {
if (DEBUG) Log.d(TAG, "Ignoring toggle for element with no position.");
return;
}
String id = mAdapter.getModelId(position);
if (id != null) {
toggleSelection(id);
}
}
/**
* Toggles selection on the item with the given model ID.
*
* @param modelId
*/
public void toggleSelection(String modelId) {
assert(modelId != null);
boolean changed = false;
if (mSelection.contains(modelId)) {
changed = attemptDeselect(modelId);
} else {
changed = attemptSelect(modelId);
}
if (changed) {
notifySelectionChanged();
}
}
/**
* Starts a range selection. If a range selection is already active, this will start a new range
* selection (which will reset the range anchor).
*
* @param pos The anchor position for the selection range.
*/
void startRangeSelection(int pos) {
attemptSelect(mAdapter.getModelId(pos));
setSelectionRangeBegin(pos);
}
/**
* Sets the end point for the current range selection, started by a call to
* {@link #startRangeSelection(int)}. This function should only be called when a range selection
* is active (see {@link #isRangeSelectionActive()}. Items in the range [anchor, end] will be
* selected.
*
* @param pos The new end position for the selection range.
*/
void snapRangeSelection(int pos) {
assert(mRanger != null);
mRanger.snapSelection(pos);
notifySelectionChanged();
}
/**
* Stops an in-progress range selection.
*/
void endRangeSelection() {
mRanger = null;
}
/**
* @return Whether or not there is a current range selection active.
*/
boolean isRangeSelectionActive() {
return mRanger != null;
}
/**
* Sets the magic location at which a selection range begins (the selection anchor). This value
* is consulted when determining how to extend, and modify selection ranges. Calling this when a
* range selection is active will reset the range selection.
*
* @throws IllegalStateException if {@code position} is not already be selected
* @param position
*/
void setSelectionRangeBegin(int position) {
if (position == RecyclerView.NO_POSITION) {
return;
}
if (mSelection.contains(mAdapter.getModelId(position))) {
mRanger = new Range(position);
}
}
/**
* Try to set selection state for all elements in range. Not that callbacks can cancel selection
* of specific items, so some or even all items may not reflect the desired state after the
* update is complete.
*
* @param begin Adapter position for range start (inclusive).
* @param end Adapter position for range end (inclusive).
* @param selected New selection state.
*/
private void updateRange(int begin, int end, boolean selected) {
assert(end >= begin);
for (int i = begin; i <= end; i++) {
String id = mAdapter.getModelId(i);
if (id == null) {
continue;
}
if (selected) {
boolean canSelect = notifyBeforeItemStateChange(id, true);
if (canSelect) {
if (mSingleSelect && hasSelection()) {
clearSelectionQuietly();
}
selectAndNotify(id);
}
} else {
attemptDeselect(id);
}
}
}
/**
* @param modelId
* @return True if the update was applied.
*/
private boolean selectAndNotify(String modelId) {
boolean changed = mSelection.add(modelId);
if (changed) {
notifyItemStateChanged(modelId, true);
}
return changed;
}
/**
* @param id
* @return True if the update was applied.
*/
private boolean attemptDeselect(String id) {
assert(id != null);
if (notifyBeforeItemStateChange(id, false)) {
mSelection.remove(id);
notifyItemStateChanged(id, false);
if (DEBUG) Log.d(TAG, "Selection after deselect: " + mSelection);
return true;
} else {
if (DEBUG) Log.d(TAG, "Select cancelled by listener.");
return false;
}
}
/**
* @param id
* @return True if the update was applied.
*/
private boolean attemptSelect(String id) {
assert(id != null);
boolean canSelect = notifyBeforeItemStateChange(id, true);
if (!canSelect) {
return false;
}
if (mSingleSelect && hasSelection()) {
clearSelectionQuietly();
}
selectAndNotify(id);
return true;
}
private boolean notifyBeforeItemStateChange(String id, boolean nextState) {
int lastListener = mCallbacks.size() - 1;
for (int i = lastListener; i > -1; i--) {
if (!mCallbacks.get(i).onBeforeItemStateChange(id, nextState)) {
return false;
}
}
return true;
}
/**
* Notifies registered listeners when the selection status of a single item
* (identified by {@code position}) changes.
*/
private void notifyItemStateChanged(String id, boolean selected) {
assert(id != null);
int lastListener = mCallbacks.size() - 1;
for (int i = lastListener; i > -1; i--) {
mCallbacks.get(i).onItemStateChanged(id, selected);
}
mAdapter.onItemSelectionChanged(id);
}
/**
* Notifies registered listeners when the selection has changed. This
* notification should be sent only once a full series of changes
* is complete, e.g. clearingSelection, or updating the single
* selection from one item to another.
*/
private void notifySelectionChanged() {
int lastListener = mCallbacks.size() - 1;
for (int i = lastListener; i > -1; i--) {
mCallbacks.get(i).onSelectionChanged();
}
}
/**
* Class providing support for managing range selections.
*/
private final class Range {
private static final int UNDEFINED = -1;
final int mBegin;
int mEnd = UNDEFINED;
public Range(int begin) {
if (DEBUG) Log.d(TAG, "New Ranger created beginning @ " + begin);
mBegin = begin;
}
private void snapSelection(int position) {
assert(mRanger != null);
assert(position != RecyclerView.NO_POSITION);
if (mEnd == UNDEFINED || mEnd == mBegin) {
// Reset mEnd so it can be established in establishRange.
mEnd = UNDEFINED;
establishRange(position);
} else {
reviseRange(position);
}
}
private void establishRange(int position) {
assert(mRanger.mEnd == UNDEFINED);
if (position == mBegin) {
mEnd = position;
}
if (position > mBegin) {
updateRange(mBegin + 1, position, true);
} else if (position < mBegin) {
updateRange(position, mBegin - 1, true);
}
mEnd = position;
}
private void reviseRange(int position) {
assert(mEnd != UNDEFINED);
assert(mBegin != mEnd);
if (position == mEnd) {
if (DEBUG) Log.i(TAG, "Skipping no-op revision click on mEndRange.");
}
if (mEnd > mBegin) {
reviseAscendingRange(position);
} else if (mEnd < mBegin) {
reviseDescendingRange(position);
}
// the "else" case is covered by checkState at beginning of method.
mEnd = position;
}
/**
* Updates an existing ascending seleciton.
* @param position
*/
private void reviseAscendingRange(int position) {
// Reducing or reversing the range....
if (position < mEnd) {
if (position < mBegin) {
updateRange(mBegin + 1, mEnd, false);
updateRange(position, mBegin -1, true);
} else {
updateRange(position + 1, mEnd, false);
}
}
// Extending the range...
else if (position > mEnd) {
updateRange(mEnd + 1, position, true);
}
}
private void reviseDescendingRange(int position) {
// Reducing or reversing the range....
if (position > mEnd) {
if (position > mBegin) {
updateRange(mEnd, mBegin - 1, false);
updateRange(mBegin + 1, position, true);
} else {
updateRange(mEnd, position - 1, false);
}
}
// Extending the range...
else if (position < mEnd) {
updateRange(position, mEnd - 1, true);
}
}
}
/**
* Object representing the current selection. Provides read only access
* public access, and private write access.
*/
public static final class Selection implements Parcelable {
// This class tracks selected items by managing two sets: the saved selection, and the total
// selection. Saved selections are those which have been completed by tapping an item or by
// completing a band select operation. Provisional selections are selections which have been
// temporarily created by an in-progress band select operation (once the user releases the
// mouse button during a band select operation, the selected items become saved). The total
// selection is the combination of both the saved selection and the provisional
// selection. Tracking both separately is necessary to ensure that saved selections do not
// become deselected when they are removed from the provisional selection; for example, if
// item A is tapped (and selected), then an in-progress band select covers A then uncovers
// A, A should still be selected as it has been saved. To ensure this behavior, the saved
// selection must be tracked separately.
private final Set<String> mSelection;
private final Set<String> mProvisionalSelection;
private String mDirectoryKey;
public Selection() {
mSelection = new HashSet<String>();
mProvisionalSelection = new HashSet<String>();
}
/**
* Used by CREATOR.
*/
private Selection(String directoryKey, Set<String> selection) {
mDirectoryKey = directoryKey;
mSelection = selection;
mProvisionalSelection = new HashSet<String>();
}
/**
* @param id
* @return true if the position is currently selected.
*/
public boolean contains(@Nullable String id) {
return mSelection.contains(id) || mProvisionalSelection.contains(id);
}
/**
* Returns an unordered array of selected positions.
*/
public String[] getAll() {
return toList().toArray(new String[0]);
}
/**
* Returns an unordered array of selected positions (including any
* provisional selections current in effect).
*/
public List<String> toList() {
ArrayList<String> selection = new ArrayList<String>(mSelection);
selection.addAll(mProvisionalSelection);
return selection;
}
/**
* @return size of the selection.
*/
public int size() {
return mSelection.size() + mProvisionalSelection.size();
}
/**
* @return true if the selection is empty.
*/
public boolean isEmpty() {
return mSelection.isEmpty() && mProvisionalSelection.isEmpty();
}
/**
* Sets the provisional selection, which is a temporary selection that can be saved,
* canceled, or adjusted at a later time. When a new provision selection is applied, the old
* one (if it exists) is abandoned.
* @return Map of ids added or removed. Added ids have a value of true, removed are false.
*/
@VisibleForTesting
protected Map<String, Boolean> setProvisionalSelection(Set<String> newSelection) {
Map<String, Boolean> delta = new HashMap<>();
for (String id: mProvisionalSelection) {
// Mark each item that used to be in the selection but is unsaved and not in the new
// provisional selection.
if (!newSelection.contains(id) && !mSelection.contains(id)) {
delta.put(id, false);
}
}
for (String id: mSelection) {
// Mark each item that used to be in the selection but is unsaved and not in the new
// provisional selection.
if (!newSelection.contains(id)) {
delta.put(id, false);
}
}
for (String id: newSelection) {
// Mark each item that was not previously in the selection but is in the new
// provisional selection.
if (!mSelection.contains(id) && !mProvisionalSelection.contains(id)) {
delta.put(id, true);
}
}
// Now, iterate through the changes and actually add/remove them to/from the current
// selection. This could not be done in the previous loops because changing the size of
// the selection mid-iteration changes iteration order erroneously.
for (Map.Entry<String, Boolean> entry: delta.entrySet()) {
String id = entry.getKey();
if (entry.getValue()) {
mProvisionalSelection.add(id);
} else {
mProvisionalSelection.remove(id);
}
}
return delta;
}
/**
* Saves the existing provisional selection. Once the provisional selection is saved,
* subsequent provisional selections which are different from this existing one cannot
* cause items in this existing provisional selection to become deselected.
*/
@VisibleForTesting
protected void applyProvisionalSelection() {
mSelection.addAll(mProvisionalSelection);
mProvisionalSelection.clear();
}
/**
* Abandons the existing provisional selection so that all items provisionally selected are
* now deselected.
*/
@VisibleForTesting
void cancelProvisionalSelection() {
mProvisionalSelection.clear();
}
/** @hide */
@VisibleForTesting
boolean add(String id) {
if (!mSelection.contains(id)) {
mSelection.add(id);
return true;
}
return false;
}
/** @hide */
@VisibleForTesting
boolean remove(String id) {
if (mSelection.contains(id)) {
mSelection.remove(id);
return true;
}
return false;
}
public void clear() {
mSelection.clear();
}
/**
* Trims this selection to be the intersection of itself with the set of given IDs.
*/
public void intersect(Collection<String> ids) {
mSelection.retainAll(ids);
mProvisionalSelection.retainAll(ids);
}
@VisibleForTesting
void copyFrom(Selection source) {
mSelection.clear();
mSelection.addAll(source.mSelection);
mProvisionalSelection.clear();
mProvisionalSelection.addAll(source.mProvisionalSelection);
}
@Override
public String toString() {
if (size() <= 0) {
return "size=0, items=[]";
}
StringBuilder buffer = new StringBuilder(size() * 28);
buffer.append("Selection{")
.append("applied{size=" + mSelection.size())
.append(", entries=" + mSelection)
.append("}, provisional{size=" + mProvisionalSelection.size())
.append(", entries=" + mProvisionalSelection)
.append("}}");
return buffer.toString();
}
@Override
public int hashCode() {
return mSelection.hashCode() ^ mProvisionalSelection.hashCode();
}
@Override
public boolean equals(Object that) {
if (this == that) {
return true;
}
if (!(that instanceof Selection)) {
return false;
}
return mSelection.equals(((Selection) that).mSelection) &&
mProvisionalSelection.equals(((Selection) that).mProvisionalSelection);
}
/**
* Sets the state key for this selection, which allows us to match selections
* to particular states (of DirectoryFragment). Basically this lets us avoid
* loading a persisted selection in the wrong directory.
*/
public void setDirectoryKey(String key) {
mDirectoryKey = key;
}
/**
* Sets the state key for this selection, which allows us to match selections
* to particular states (of DirectoryFragment). Basically this lets us avoid
* loading a persisted selection in the wrong directory.
*/
public boolean hasDirectoryKey(String key) {
return key.equals(mDirectoryKey);
}
@Override
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(mDirectoryKey);
dest.writeStringList(new ArrayList<>(mSelection));
// We don't include provisional selection since it is
// typically coupled to some other runtime state (like a band).
}
public static final ClassLoaderCreator<Selection> CREATOR =
new ClassLoaderCreator<Selection>() {
@Override
public Selection createFromParcel(Parcel in) {
return createFromParcel(in, null);
}
@Override
public Selection createFromParcel(Parcel in, ClassLoader loader) {
String directoryKey = in.readString();
ArrayList<String> selected = new ArrayList<>();
in.readStringList(selected);
return new Selection(directoryKey, new HashSet<String>(selected));
}
@Override
public Selection[] newArray(int size) {
return new Selection[size];
}
};
}
/**
* Provides functionality for BandController. Exists primarily to tests that are
* fully isolated from RecyclerView.
*/
interface SelectionEnvironment {
void showBand(Rect rect);
void hideBand();
void addOnScrollListener(RecyclerView.OnScrollListener listener);
void removeOnScrollListener(RecyclerView.OnScrollListener listener);
void scrollBy(int dy);
int getHeight();
void invalidateView();
void runAtNextFrame(Runnable r);
void removeCallback(Runnable r);
Point createAbsolutePoint(Point relativePoint);
Rect getAbsoluteRectForChildViewAt(int index);
int getAdapterPositionAt(int index);
int getColumnCount();
int getChildCount();
int getVisibleChildCount();
/**
* Layout items are excluded from the GridModel.
*/
boolean isLayoutItem(int adapterPosition);
/**
* Items may be in the adapter, but without an attached view.
*/
boolean hasView(int adapterPosition);
}
/** Recycler view facade implementation backed by good ol' RecyclerView. */
private static final class RuntimeSelectionEnvironment implements SelectionEnvironment {
private final RecyclerView mView;
private final Drawable mBand;
private boolean mIsOverlayShown = false;
RuntimeSelectionEnvironment(RecyclerView view) {
mView = view;
mBand = mView.getContext().getTheme().getDrawable(R.drawable.band_select_overlay);
}
@Override
public int getAdapterPositionAt(int index) {
return mView.getChildAdapterPosition(mView.getChildAt(index));
}
@Override
public void addOnScrollListener(RecyclerView.OnScrollListener listener) {
mView.addOnScrollListener(listener);
}
@Override
public void removeOnScrollListener(RecyclerView.OnScrollListener listener) {
mView.removeOnScrollListener(listener);
}
@Override
public Point createAbsolutePoint(Point relativePoint) {
return new Point(relativePoint.x + mView.computeHorizontalScrollOffset(),
relativePoint.y + mView.computeVerticalScrollOffset());
}
@Override
public Rect getAbsoluteRectForChildViewAt(int index) {
final View child = mView.getChildAt(index);
final Rect childRect = new Rect();
child.getHitRect(childRect);
childRect.left += mView.computeHorizontalScrollOffset();
childRect.right += mView.computeHorizontalScrollOffset();
childRect.top += mView.computeVerticalScrollOffset();
childRect.bottom += mView.computeVerticalScrollOffset();
return childRect;
}
@Override
public int getChildCount() {
return mView.getAdapter().getItemCount();
}
@Override
public int getVisibleChildCount() {
return mView.getChildCount();
}
@Override
public int getColumnCount() {
RecyclerView.LayoutManager layoutManager = mView.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
return ((GridLayoutManager) layoutManager).getSpanCount();
}
// Otherwise, it is a list with 1 column.
return 1;
}
@Override
public int getHeight() {
return mView.getHeight();
}
@Override
public void invalidateView() {
mView.invalidate();
}
@Override
public void runAtNextFrame(Runnable r) {
mView.postOnAnimation(r);
}
@Override
public void removeCallback(Runnable r) {
mView.removeCallbacks(r);
}
@Override
public void scrollBy(int dy) {
mView.scrollBy(0, dy);
}
@Override
public void showBand(Rect rect) {
mBand.setBounds(rect);
if (!mIsOverlayShown) {
mView.getOverlay().add(mBand);
}
}
@Override
public void hideBand() {
mView.getOverlay().remove(mBand);
}
@Override
public boolean isLayoutItem(int pos) {
// The band selection model only operates on documents and directories. Exclude other
// types of adapter items (e.g. whitespace items like dividers).
RecyclerView.ViewHolder vh = mView.findViewHolderForAdapterPosition(pos);
switch (vh.getItemViewType()) {
case ITEM_TYPE_DOCUMENT:
case ITEM_TYPE_DIRECTORY:
return false;
default:
return true;
}
}
@Override
public boolean hasView(int pos) {
return mView.findViewHolderForAdapterPosition(pos) != null;
}
}
public interface Callback {
/**
* Called when an item is selected or unselected while in selection mode.
*
* @param position Adapter position of the item that was checked or unchecked
* @param selected <code>true</code> if the item is now selected, <code>false</code>
* if the item is now unselected.
*/
public void onItemStateChanged(String id, boolean selected);
/**
* Called prior to an item changing state. Callbacks can cancel
* the change at {@code position} by returning {@code false}.
*
* @param id Adapter position of the item that was checked or unchecked
* @param selected <code>true</code> if the item is to be selected, <code>false</code>
* if the item is to be unselected.
*/
public boolean onBeforeItemStateChange(String id, boolean selected);
/**
* Called immediately after completion of any set of changes.
*/
public void onSelectionChanged();
}
/**
* Provides mouse driven band-select support when used in conjunction with {@link RecyclerView}
* and {@link MultiSelectManager}. This class is responsible for rendering the band select
* overlay and selecting overlaid items via MultiSelectManager.
*/
public class BandController extends RecyclerView.OnScrollListener
implements GridModel.OnSelectionChangedListener {
private static final int NOT_SET = -1;
private final Runnable mModelBuilder;
@Nullable private Rect mBounds;
@Nullable private Point mCurrentPosition;
@Nullable private Point mOrigin;
@Nullable private GridModel mModel;
// The time at which the current band selection-induced scroll began. If no scroll is in
// progress, the value is NOT_SET.
private long mScrollStartTime = NOT_SET;
private final Runnable mViewScroller = new ViewScroller();
public BandController() {
mEnvironment.addOnScrollListener(this);
mModelBuilder = new Runnable() {
@Override
public void run() {
mModel = new GridModel(mEnvironment, mAdapter);
mModel.addOnSelectionChangedListener(BandController.this);
}
};
}
public boolean handleEvent(MotionInputEvent e) {
// b/23793622 notes the fact that we *never* receive ACTION_DOWN
// events in onTouchEvent. Where it not for this issue, we'd
// push start handling down into handleInputEvent.
if (mBandManager.shouldStart(e)) {
// endBandSelect is handled in handleInputEvent.
mBandManager.startBandSelect(e.getOrigin());
} else if (mBandManager.isActive()
&& e.isMouseEvent()
&& e.isActionUp()) {
// Same issue here w b/23793622. The ACTION_UP event
// is only evert dispatched to onTouchEvent when
// there is some associated motion. If a user taps
// mouse, but doesn't move, then band select gets
// started BUT not ended. Causing phantom
// bands to appear when the user later clicks to start
// band select.
mBandManager.processInputEvent(e);
}
return isActive();
}
private boolean isActive() {
return mModel != null;
}
/**
* Handle a change in layout by cleaning up and getting rid of the old model and creating
* a new model which will track the new layout.
*/
public void handleLayoutChanged() {
if (mModel != null) {
mModel.removeOnSelectionChangedListener(this);
mModel.stopListening();
// build a new model, all fresh and happy.
mModelBuilder.run();
}
}
boolean shouldStart(MotionInputEvent e) {
return !isActive()
&& e.isMouseEvent() // a mouse
&& e.isActionDown() // the initial button press
&& mAdapter.getItemCount() > 0
&& e.getItemPosition() == RecyclerView.NO_ID; // in empty space
}
boolean shouldStop(InputEvent input) {
return isActive()
&& input.isMouseEvent()
&& input.isActionUp();
}
/**
* Processes a MotionEvent by starting, ending, or resizing the band select overlay.
* @param input
*/
private void processInputEvent(InputEvent input) {
assert(input.isMouseEvent());
if (shouldStop(input)) {
endBandSelect();
return;
}
// We shouldn't get any events in this method when band select is not active,
// but it turns some guests show up late to the party.
if (!isActive()) {
return;
}
mCurrentPosition = input.getOrigin();
mModel.resizeSelection(input.getOrigin());
scrollViewIfNecessary();
resizeBandSelectRectangle();
}
/**
* Starts band select by adding the drawable to the RecyclerView's overlay.
*/
private void startBandSelect(Point origin) {
if (DEBUG) Log.d(TAG, "Starting band select @ " + origin);
mOrigin = origin;
mModelBuilder.run(); // Creates a new selection model.
mModel.startSelection(mOrigin);
}
/**
* Scrolls the view if necessary.
*/
private void scrollViewIfNecessary() {
mEnvironment.removeCallback(mViewScroller);
mViewScroller.run();
mEnvironment.invalidateView();
}
/**
* Resizes the band select rectangle by using the origin and the current pointer position as
* two opposite corners of the selection.
*/
private void resizeBandSelectRectangle() {
mBounds = new Rect(Math.min(mOrigin.x, mCurrentPosition.x),
Math.min(mOrigin.y, mCurrentPosition.y),
Math.max(mOrigin.x, mCurrentPosition.x),
Math.max(mOrigin.y, mCurrentPosition.y));
mEnvironment.showBand(mBounds);
}
/**
* Ends band select by removing the overlay.
*/
private void endBandSelect() {
if (DEBUG) Log.d(TAG, "Ending band select.");
mEnvironment.hideBand();
mSelection.applyProvisionalSelection();
mModel.endSelection();
int firstSelected = mModel.getPositionNearestOrigin();
if (firstSelected != NOT_SET) {
if (mSelection.contains(mAdapter.getModelId(firstSelected))) {
// TODO: firstSelected should really be lastSelected, we want to anchor the item
// where the mouse-up occurred.
setSelectionRangeBegin(firstSelected);
} else {
// TODO: Check if this is really happening.
Log.w(TAG, "First selected by band is NOT in selection!");
}
}
mModel = null;
mOrigin = null;
}
@Override
public void onSelectionChanged(Set<String> updatedSelection) {
Map<String, Boolean> delta = mSelection.setProvisionalSelection(updatedSelection);
for (Map.Entry<String, Boolean> entry: delta.entrySet()) {
notifyItemStateChanged(entry.getKey(), entry.getValue());
}
notifySelectionChanged();
}
@Override
public boolean onBeforeItemStateChange(String id, boolean nextState) {
return notifyBeforeItemStateChange(id, nextState);
}
private class ViewScroller implements Runnable {
/**
* The number of milliseconds of scrolling at which scroll speed continues to increase.
* At first, the scroll starts slowly; then, the rate of scrolling increases until it
* reaches its maximum value at after this many milliseconds.
*/
private static final long SCROLL_ACCELERATION_LIMIT_TIME_MS = 2000;
@Override
public void run() {
// Compute the number of pixels the pointer's y-coordinate is past the view.
// Negative values mean the pointer is at or before the top of the view, and
// positive values mean that the pointer is at or after the bottom of the view. Note
// that one additional pixel is added here so that the view still scrolls when the
// pointer is exactly at the top or bottom.
int pixelsPastView = 0;
if (mCurrentPosition.y <= 0) {
pixelsPastView = mCurrentPosition.y - 1;
} else if (mCurrentPosition.y >= mEnvironment.getHeight() - 1) {
pixelsPastView = mCurrentPosition.y - mEnvironment.getHeight() + 1;
}
if (!isActive() || pixelsPastView == 0) {
// If band selection is inactive, or if it is active but not at the edge of the
// view, no scrolling is necessary.
mScrollStartTime = NOT_SET;
return;
}
if (mScrollStartTime == NOT_SET) {
// If the pointer was previously not at the edge of the view but now is, set the
// start time for the scroll.
mScrollStartTime = System.currentTimeMillis();
}
// Compute the number of pixels to scroll, and scroll that many pixels.
final int numPixels = computeScrollDistance(
pixelsPastView, System.currentTimeMillis() - mScrollStartTime);
mEnvironment.scrollBy(numPixels);
mEnvironment.removeCallback(mViewScroller);
mEnvironment.runAtNextFrame(this);
}
/**
* Computes the number of pixels to scroll based on how far the pointer is past the end
* of the view and how long it has been there. Roughly based on ItemTouchHelper's
* algorithm for computing the number of pixels to scroll when an item is dragged to the
* end of a {@link RecyclerView}.
* @param pixelsPastView
* @param scrollDuration
* @return
*/
private int computeScrollDistance(int pixelsPastView, long scrollDuration) {
final int maxScrollStep = mEnvironment.getHeight();
final int direction = (int) Math.signum(pixelsPastView);
final int absPastView = Math.abs(pixelsPastView);
// Calculate the ratio of how far out of the view the pointer currently resides to
// the entire height of the view.
final float outOfBoundsRatio = Math.min(
1.0f, (float) absPastView / mEnvironment.getHeight());
// Interpolate this ratio and use it to compute the maximum scroll that should be
// possible for this step.
final float cappedScrollStep =
direction * maxScrollStep * smoothOutOfBoundsRatio(outOfBoundsRatio);
// Likewise, calculate the ratio of the time spent in the scroll to the limit.
final float timeRatio = Math.min(
1.0f, (float) scrollDuration / SCROLL_ACCELERATION_LIMIT_TIME_MS);
// Interpolate this ratio and use it to compute the final number of pixels to
// scroll.
final int numPixels = (int) (cappedScrollStep * smoothTimeRatio(timeRatio));
// If the final number of pixels to scroll ends up being 0, the view should still
// scroll at least one pixel.
return numPixels != 0 ? numPixels : direction;
}
/**
* Interpolates the given out of bounds ratio on a curve which starts at (0,0) and ends
* at (1,1) and quickly approaches 1 near the start of that interval. This ensures that
* drags that are at the edge or barely past the edge of the view still cause sufficient
* scrolling. The equation y=(x-1)^5+1 is used, but this could also be tweaked if
* needed.
* @param ratio A ratio which is in the range [0, 1].
* @return A "smoothed" value, also in the range [0, 1].
*/
private float smoothOutOfBoundsRatio(float ratio) {
return (float) Math.pow(ratio - 1.0f, 5) + 1.0f;
}
/**
* Interpolates the given time ratio on a curve which starts at (0,0) and ends at (1,1)
* and stays close to 0 for most input values except those very close to 1. This ensures
* that scrolls start out very slowly but speed up drastically after the scroll has been
* in progress close to SCROLL_ACCELERATION_LIMIT_TIME_MS. The equation y=x^5 is used,
* but this could also be tweaked if needed.
* @param ratio A ratio which is in the range [0, 1].
* @return A "smoothed" value, also in the range [0, 1].
*/
private float smoothTimeRatio(float ratio) {
return (float) Math.pow(ratio, 5);
}
};
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (!isActive()) {
return;
}
// Adjust the y-coordinate of the origin the opposite number of pixels so that the
// origin remains in the same place relative to the view's items.
mOrigin.y -= dy;
resizeBandSelectRectangle();
}
}
/**
* Provides a band selection item model for views within a RecyclerView. This class queries the
* RecyclerView to determine where its items are placed; then, once band selection is underway,
* it alerts listeners of which items are covered by the selections.
*/
public static final class GridModel extends RecyclerView.OnScrollListener {
public static final int NOT_SET = -1;
// Enum values used to determine the corner at which the origin is located within the
private static final int UPPER = 0x00;
private static final int LOWER = 0x01;
private static final int LEFT = 0x00;
private static final int RIGHT = 0x02;
private static final int UPPER_LEFT = UPPER | LEFT;
private static final int UPPER_RIGHT = UPPER | RIGHT;
private static final int LOWER_LEFT = LOWER | LEFT;
private static final int LOWER_RIGHT = LOWER | RIGHT;
private final SelectionEnvironment mHelper;
private final DocumentsAdapter mAdapter;
private final List<OnSelectionChangedListener> mOnSelectionChangedListeners =
new ArrayList<>();
// Map from the x-value of the left side of a SparseBooleanArray of adapter positions, keyed
// by their y-offset. For example, if the first column of the view starts at an x-value of 5,
// mColumns.get(5) would return an array of positions in that column. Within that array, the
// value for key y is the adapter position for the item whose y-offset is y.
private final SparseArray<SparseIntArray> mColumns = new SparseArray<>();
// List of limits along the x-axis (columns).
// This list is sorted from furthest left to furthest right.
private final List<Limits> mColumnBounds = new ArrayList<>();
// List of limits along the y-axis (rows). Note that this list only contains items which
// have been in the viewport.
private final List<Limits> mRowBounds = new ArrayList<>();
// The adapter positions which have been recorded so far.
private final SparseBooleanArray mKnownPositions = new SparseBooleanArray();
// Array passed to registered OnSelectionChangedListeners. One array is created and reused
// throughout the lifetime of the object.
private final Set<String> mSelection = new HashSet<>();
// The current pointer (in absolute positioning from the top of the view).
private Point mPointer = null;
// The bounds of the band selection.
private RelativePoint mRelativeOrigin;
private RelativePoint mRelativePointer;
private boolean mIsActive;
// Tracks where the band select originated from. This is used to determine where selections
// should expand from when Shift+click is used.
private int mPositionNearestOrigin = NOT_SET;
GridModel(SelectionEnvironment helper, DocumentsAdapter adapter) {
mHelper = helper;
mAdapter = adapter;
mHelper.addOnScrollListener(this);
}
/**
* Stops listening to the view's scrolls. Call this function before discarding a
* BandSelecModel object to prevent memory leaks.
*/
void stopListening() {
mHelper.removeOnScrollListener(this);
}
/**
* Start a band select operation at the given point.
* @param relativeOrigin The origin of the band select operation, relative to the viewport.
* For example, if the view is scrolled to the bottom, the top-left of the viewport
* would have a relative origin of (0, 0), even though its absolute point has a higher
* y-value.
*/
void startSelection(Point relativeOrigin) {
recordVisibleChildren();
if (isEmpty()) {
// The selection band logic works only if there is at least one visible child.
return;
}
mIsActive = true;
mPointer = mHelper.createAbsolutePoint(relativeOrigin);
mRelativeOrigin = new RelativePoint(mPointer);
mRelativePointer = new RelativePoint(mPointer);
computeCurrentSelection();
notifyListeners();
}
/**
* Resizes the selection by adjusting the pointer (i.e., the corner of the selection
* opposite the origin.
* @param relativePointer The pointer (opposite of the origin) of the band select operation,
* relative to the viewport. For example, if the view is scrolled to the bottom, the
* top-left of the viewport would have a relative origin of (0, 0), even though its
* absolute point has a higher y-value.
*/
@VisibleForTesting
void resizeSelection(Point relativePointer) {
mPointer = mHelper.createAbsolutePoint(relativePointer);
updateModel();
}
/**
* Ends the band selection.
*/
void endSelection() {
mIsActive = false;
}
/**
* @return The adapter position for the item nearest the origin corresponding to the latest
* band select operation, or NOT_SET if the selection did not cover any items.
*/
int getPositionNearestOrigin() {
return mPositionNearestOrigin;
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (!mIsActive) {
return;
}
mPointer.x += dx;
mPointer.y += dy;
recordVisibleChildren();
updateModel();
}
/**
* Queries the view for all children and records their location metadata.
*/
private void recordVisibleChildren() {
for (int i = 0; i < mHelper.getVisibleChildCount(); i++) {
int adapterPosition = mHelper.getAdapterPositionAt(i);
// Sometimes the view is not attached, as we notify the multi selection manager
// synchronously, while views are attached asynchronously. As a result items which
// are in the adapter may not actually have a corresponding view (yet).
if (mHelper.hasView(adapterPosition) &&
!mHelper.isLayoutItem(adapterPosition) &&
!mKnownPositions.get(adapterPosition)) {
mKnownPositions.put(adapterPosition, true);
recordItemData(mHelper.getAbsoluteRectForChildViewAt(i), adapterPosition);
}
}
}
/**
* Checks if there are any recorded children.
*/
private boolean isEmpty() {
return mColumnBounds.size() == 0 || mRowBounds.size() == 0;
}
/**
* Updates the limits lists and column map with the given item metadata.
* @param absoluteChildRect The absolute rectangle for the child view being processed.
* @param adapterPosition The position of the child view being processed.
*/
private void recordItemData(Rect absoluteChildRect, int adapterPosition) {
if (mColumnBounds.size() != mHelper.getColumnCount()) {
// If not all x-limits have been recorded, record this one.
recordLimits(
mColumnBounds, new Limits(absoluteChildRect.left, absoluteChildRect.right));
}
recordLimits(mRowBounds, new Limits(absoluteChildRect.top, absoluteChildRect.bottom));
SparseIntArray columnList = mColumns.get(absoluteChildRect.left);
if (columnList == null) {
columnList = new SparseIntArray();
mColumns.put(absoluteChildRect.left, columnList);
}
columnList.put(absoluteChildRect.top, adapterPosition);
}
/**
* Ensures limits exists within the sorted list limitsList, and adds it to the list if it
* does not exist.
*/
private void recordLimits(List<Limits> limitsList, Limits limits) {
int index = Collections.binarySearch(limitsList, limits);
if (index < 0) {
limitsList.add(~index, limits);
}
}
/**
* Handles a moved pointer; this function determines whether the pointer movement resulted
* in a selection change and, if it has, notifies listeners of this change.
*/
private void updateModel() {
RelativePoint old = mRelativePointer;
mRelativePointer = new RelativePoint(mPointer);
if (old != null && mRelativePointer.equals(old)) {
return;
}
computeCurrentSelection();
notifyListeners();
}
/**
* Computes the currently-selected items.
*/
private void computeCurrentSelection() {
if (areItemsCoveredByBand(mRelativePointer, mRelativeOrigin)) {
updateSelection(computeBounds());
} else {
mSelection.clear();
mPositionNearestOrigin = NOT_SET;
}
}
/**
* Notifies all listeners of a selection change. Note that this function simply passes
* mSelection, so computeCurrentSelection() should be called before this
* function.
*/
private void notifyListeners() {
for (OnSelectionChangedListener listener : mOnSelectionChangedListeners) {
listener.onSelectionChanged(mSelection);
}
}
/**
* @param rect Rectangle including all covered items.
*/
private void updateSelection(Rect rect) {
int columnStart =
Collections.binarySearch(mColumnBounds, new Limits(rect.left, rect.left));
assert(columnStart >= 0);
int columnEnd = columnStart;
for (int i = columnStart; i < mColumnBounds.size()
&& mColumnBounds.get(i).lowerLimit <= rect.right; i++) {
columnEnd = i;
}
int rowStart = Collections.binarySearch(mRowBounds, new Limits(rect.top, rect.top));
if (rowStart < 0) {
mPositionNearestOrigin = NOT_SET;
return;
}
int rowEnd = rowStart;
for (int i = rowStart; i < mRowBounds.size()
&& mRowBounds.get(i).lowerLimit <= rect.bottom; i++) {
rowEnd = i;
}
updateSelection(columnStart, columnEnd, rowStart, rowEnd);
}
/**
* Computes the selection given the previously-computed start- and end-indices for each
* row and column.
*/
private void updateSelection(
int columnStartIndex, int columnEndIndex, int rowStartIndex, int rowEndIndex) {
if (DEBUG) Log.d(TAG, String.format("updateSelection: %d, %d, %d, %d",
columnStartIndex, columnEndIndex, rowStartIndex, rowEndIndex));
mSelection.clear();
for (int column = columnStartIndex; column <= columnEndIndex; column++) {
SparseIntArray items = mColumns.get(mColumnBounds.get(column).lowerLimit);
for (int row = rowStartIndex; row <= rowEndIndex; row++) {
// The default return value for SparseIntArray.get is 0, which is a valid
// position. Use a sentry value to prevent erroneously selecting item 0.
final int rowKey = mRowBounds.get(row).lowerLimit;
int position = items.get(rowKey, NOT_SET);
if (position != NOT_SET) {
String id = mAdapter.getModelId(position);
if (id != null) {
// The adapter inserts items for UI layout purposes that aren't associated
// with files. Those will have a null model ID. Don't select them.
if (canSelect(id)) {
mSelection.add(id);
}
}
if (isPossiblePositionNearestOrigin(column, columnStartIndex, columnEndIndex,
row, rowStartIndex, rowEndIndex)) {
// If this is the position nearest the origin, record it now so that it
// can be returned by endSelection() later.
mPositionNearestOrigin = position;
}
}
}
}
}
/**
* @return True if the item is selectable.
*/
private boolean canSelect(String id) {
// TODO: Simplify the logic, so the check whether we can select is done in one place.
// Consider injecting FragmentTuner, or move the checks from MultiSelectManager to
// Selection.
for (OnSelectionChangedListener listener : mOnSelectionChangedListeners) {
if (!listener.onBeforeItemStateChange(id, true)) {
return false;
}
}
return true;
}
/**
* @return Returns true if the position is the nearest to the origin, or, in the case of the
* lower-right corner, whether it is possible that the position is the nearest to the
* origin. See comment below for reasoning for this special case.
*/
private boolean isPossiblePositionNearestOrigin(int columnIndex, int columnStartIndex,
int columnEndIndex, int rowIndex, int rowStartIndex, int rowEndIndex) {
int corner = computeCornerNearestOrigin();
switch (corner) {
case UPPER_LEFT:
return columnIndex == columnStartIndex && rowIndex == rowStartIndex;
case UPPER_RIGHT:
return columnIndex == columnEndIndex && rowIndex == rowStartIndex;
case LOWER_LEFT:
return columnIndex == columnStartIndex && rowIndex == rowEndIndex;
case LOWER_RIGHT:
// Note that in some cases, the last row will not have as many items as there
// are columns (e.g., if there are 4 items and 3 columns, the second row will
// only have one item in the first column). This function is invoked for each
// position from left to right, so return true for any position in the bottom
// row and only the right-most position in the bottom row will be recorded.
return rowIndex == rowEndIndex;
default:
throw new RuntimeException("Invalid corner type.");
}
}
/**
* Listener for changes in which items have been band selected.
*/
static interface OnSelectionChangedListener {
public void onSelectionChanged(Set<String> updatedSelection);
public boolean onBeforeItemStateChange(String id, boolean nextState);
}
void addOnSelectionChangedListener(OnSelectionChangedListener listener) {
mOnSelectionChangedListeners.add(listener);
}
void removeOnSelectionChangedListener(OnSelectionChangedListener listener) {
mOnSelectionChangedListeners.remove(listener);
}
/**
* Limits of a view item. For example, if an item's left side is at x-value 5 and its right side
* is at x-value 10, the limits would be from 5 to 10. Used to record the left- and right sides
* of item columns and the top- and bottom sides of item rows so that it can be determined
* whether the pointer is located within the bounds of an item.
*/
private static class Limits implements Comparable<Limits> {
int lowerLimit;
int upperLimit;
Limits(int lowerLimit, int upperLimit) {
this.lowerLimit = lowerLimit;
this.upperLimit = upperLimit;
}
@Override
public int compareTo(Limits other) {
return lowerLimit - other.lowerLimit;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof Limits)) {
return false;
}
return ((Limits) other).lowerLimit == lowerLimit &&
((Limits) other).upperLimit == upperLimit;
}
@Override
public String toString() {
return "(" + lowerLimit + ", " + upperLimit + ")";
}
}
/**
* The location of a coordinate relative to items. This class represents a general area of the
* view as it relates to band selection rather than an explicit point. For example, two
* different points within an item are considered to have the same "location" because band
* selection originating within the item would select the same items no matter which point
* was used. Same goes for points between items as well as those at the very beginning or end
* of the view.
*
* Tracking a coordinate (e.g., an x-value) as a CoordinateLocation instead of as an int has the
* advantage of tying the value to the Limits of items along that axis. This allows easy
* selection of items within those Limits as opposed to a search through every item to see if a
* given coordinate value falls within those Limits.
*/
private static class RelativeCoordinate
implements Comparable<RelativeCoordinate> {
/**
* Location describing points after the last known item.
*/
static final int AFTER_LAST_ITEM = 0;
/**
* Location describing points before the first known item.
*/
static final int BEFORE_FIRST_ITEM = 1;
/**
* Location describing points between two items.
*/
static final int BETWEEN_TWO_ITEMS = 2;
/**
* Location describing points within the limits of one item.
*/
static final int WITHIN_LIMITS = 3;
/**
* The type of this coordinate, which is one of AFTER_LAST_ITEM, BEFORE_FIRST_ITEM,
* BETWEEN_TWO_ITEMS, or WITHIN_LIMITS.
*/
final int type;
/**
* The limits before the coordinate; only populated when type == WITHIN_LIMITS or type ==
* BETWEEN_TWO_ITEMS.
*/
Limits limitsBeforeCoordinate;
/**
* The limits after the coordinate; only populated when type == BETWEEN_TWO_ITEMS.
*/
Limits limitsAfterCoordinate;
// Limits of the first known item; only populated when type == BEFORE_FIRST_ITEM.
Limits mFirstKnownItem;
// Limits of the last known item; only populated when type == AFTER_LAST_ITEM.
Limits mLastKnownItem;
/**
* @param limitsList The sorted limits list for the coordinate type. If this
* CoordinateLocation is an x-value, mXLimitsList should be passed; otherwise,
* mYLimitsList should be pased.
* @param value The coordinate value.
*/
RelativeCoordinate(List<Limits> limitsList, int value) {
int index = Collections.binarySearch(limitsList, new Limits(value, value));
if (index >= 0) {
this.type = WITHIN_LIMITS;
this.limitsBeforeCoordinate = limitsList.get(index);
} else if (~index == 0) {
this.type = BEFORE_FIRST_ITEM;
this.mFirstKnownItem = limitsList.get(0);
} else if (~index == limitsList.size()) {
Limits lastLimits = limitsList.get(limitsList.size() - 1);
if (lastLimits.lowerLimit <= value && value <= lastLimits.upperLimit) {
this.type = WITHIN_LIMITS;
this.limitsBeforeCoordinate = lastLimits;
} else {
this.type = AFTER_LAST_ITEM;
this.mLastKnownItem = lastLimits;
}
} else {
Limits limitsBeforeIndex = limitsList.get(~index - 1);
if (limitsBeforeIndex.lowerLimit <= value && value <= limitsBeforeIndex.upperLimit) {
this.type = WITHIN_LIMITS;
this.limitsBeforeCoordinate = limitsList.get(~index - 1);
} else {
this.type = BETWEEN_TWO_ITEMS;
this.limitsBeforeCoordinate = limitsList.get(~index - 1);
this.limitsAfterCoordinate = limitsList.get(~index);
}
}
}
int toComparisonValue() {
if (type == BEFORE_FIRST_ITEM) {
return mFirstKnownItem.lowerLimit - 1;
} else if (type == AFTER_LAST_ITEM) {
return mLastKnownItem.upperLimit + 1;
} else if (type == BETWEEN_TWO_ITEMS) {
return limitsBeforeCoordinate.upperLimit + 1;
} else {
return limitsBeforeCoordinate.lowerLimit;
}
}
@Override
public boolean equals(Object other) {
if (!(other instanceof RelativeCoordinate)) {
return false;
}
RelativeCoordinate otherCoordinate = (RelativeCoordinate) other;
return toComparisonValue() == otherCoordinate.toComparisonValue();
}
@Override
public int compareTo(RelativeCoordinate other) {
return toComparisonValue() - other.toComparisonValue();
}
}
/**
* The location of a point relative to the Limits of nearby items; consists of both an x- and
* y-RelativeCoordinateLocation.
*/
private class RelativePoint {
final RelativeCoordinate xLocation;
final RelativeCoordinate yLocation;
RelativePoint(Point point) {
this.xLocation = new RelativeCoordinate(mColumnBounds, point.x);
this.yLocation = new RelativeCoordinate(mRowBounds, point.y);
}
@Override
public boolean equals(Object other) {
if (!(other instanceof RelativePoint)) {
return false;
}
RelativePoint otherPoint = (RelativePoint) other;
return xLocation.equals(otherPoint.xLocation) && yLocation.equals(otherPoint.yLocation);
}
}
/**
* Generates a rectangle which contains the items selected by the pointer and origin.
* @return The rectangle, or null if no items were selected.
*/
private Rect computeBounds() {
Rect rect = new Rect();
rect.left = getCoordinateValue(
min(mRelativeOrigin.xLocation, mRelativePointer.xLocation),
mColumnBounds,
true);
rect.right = getCoordinateValue(
max(mRelativeOrigin.xLocation, mRelativePointer.xLocation),
mColumnBounds,
false);
rect.top = getCoordinateValue(
min(mRelativeOrigin.yLocation, mRelativePointer.yLocation),
mRowBounds,
true);
rect.bottom = getCoordinateValue(
max(mRelativeOrigin.yLocation, mRelativePointer.yLocation),
mRowBounds,
false);
return rect;
}
/**
* Computes the corner of the selection nearest the origin.
* @return
*/
private int computeCornerNearestOrigin() {
int cornerValue = 0;
if (mRelativeOrigin.yLocation ==
min(mRelativeOrigin.yLocation, mRelativePointer.yLocation)) {
cornerValue |= UPPER;
} else {
cornerValue |= LOWER;
}
if (mRelativeOrigin.xLocation ==
min(mRelativeOrigin.xLocation, mRelativePointer.xLocation)) {
cornerValue |= LEFT;
} else {
cornerValue |= RIGHT;
}
return cornerValue;
}
private RelativeCoordinate min(RelativeCoordinate first, RelativeCoordinate second) {
return first.compareTo(second) < 0 ? first : second;
}
private RelativeCoordinate max(RelativeCoordinate first, RelativeCoordinate second) {
return first.compareTo(second) > 0 ? first : second;
}
/**
* @return The absolute coordinate (i.e., the x- or y-value) of the given relative
* coordinate.
*/
private int getCoordinateValue(RelativeCoordinate coordinate,
List<Limits> limitsList, boolean isStartOfRange) {
switch (coordinate.type) {
case RelativeCoordinate.BEFORE_FIRST_ITEM:
return limitsList.get(0).lowerLimit;
case RelativeCoordinate.AFTER_LAST_ITEM:
return limitsList.get(limitsList.size() - 1).upperLimit;
case RelativeCoordinate.BETWEEN_TWO_ITEMS:
if (isStartOfRange) {
return coordinate.limitsAfterCoordinate.lowerLimit;
} else {
return coordinate.limitsBeforeCoordinate.upperLimit;
}
case RelativeCoordinate.WITHIN_LIMITS:
return coordinate.limitsBeforeCoordinate.lowerLimit;
}
throw new RuntimeException("Invalid coordinate value.");
}
private boolean areItemsCoveredByBand(
RelativePoint first, RelativePoint second) {
return doesCoordinateLocationCoverItems(first.xLocation, second.xLocation) &&
doesCoordinateLocationCoverItems(first.yLocation, second.yLocation);
}
private boolean doesCoordinateLocationCoverItems(
RelativeCoordinate pointerCoordinate,
RelativeCoordinate originCoordinate) {
if (pointerCoordinate.type == RelativeCoordinate.BEFORE_FIRST_ITEM &&
originCoordinate.type == RelativeCoordinate.BEFORE_FIRST_ITEM) {
return false;
}
if (pointerCoordinate.type == RelativeCoordinate.AFTER_LAST_ITEM &&
originCoordinate.type == RelativeCoordinate.AFTER_LAST_ITEM) {
return false;
}
if (pointerCoordinate.type == RelativeCoordinate.BETWEEN_TWO_ITEMS &&
originCoordinate.type == RelativeCoordinate.BETWEEN_TWO_ITEMS &&
pointerCoordinate.limitsBeforeCoordinate.equals(
originCoordinate.limitsBeforeCoordinate) &&
pointerCoordinate.limitsAfterCoordinate.equals(
originCoordinate.limitsAfterCoordinate)) {
return false;
}
return true;
}
}
}