/*
* Copyright (C) 2006 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.aviary.android.feather.widget;
import android.content.Context;
import android.database.DataSetObserver;
import android.os.Parcelable;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.util.SparseArray;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.SoundEffectConstants;
import android.view.View;
import android.view.ViewDebug;
import android.view.ViewGroup;
import android.view.accessibility.AccessibilityEvent;
import android.widget.Adapter;
import android.widget.GridView;
import android.widget.ListView;
import android.widget.Spinner;
// TODO: Auto-generated Javadoc
/**
* An AdapterView is a view whose children are determined by an {@link Adapter}.
*
* <p>
* See {@link ListView}, {@link GridView}, {@link Spinner} and {@link Gallery} for commonly used subclasses of AdapterView.
*
* <div class="special reference">
* <h3>Developer Guides</h3>
* <p>
* For more information about using AdapterView, read the <a href="{@docRoot}guide/topics/ui/binding.html">Binding to Data with
* AdapterView</a> developer guide.
* </p>
* </div>
*
* @param <T>
* the generic type
*/
public abstract class AdapterView<T extends Adapter> extends ViewGroup {
/**
* The item view type returned by {@link Adapter#getItemViewType(int)} when the adapter does not want the item's view recycled.
*/
public static final int ITEM_VIEW_TYPE_IGNORE = -1;
/**
* The item view type returned by {@link Adapter#getItemViewType(int)} when the item is a header or footer.
*/
public static final int ITEM_VIEW_TYPE_HEADER_OR_FOOTER = -2;
int mFirstPosition = 0;
/**
* The offset in pixels from the top of the AdapterView to the top of the view to select during the next layout.
*/
int mSpecificTop;
/** Position from which to start looking for mSyncRowId. */
int mSyncPosition;
/** Row id to look for when data has changed. */
long mSyncRowId = INVALID_ROW_ID;
/** Height of the view when mSyncPosition and mSyncRowId where set. */
long mSyncHeight;
/** True if we need to sync to mSyncRowId. */
boolean mNeedSync = false;
/**
* Indicates whether to sync based on the selection or position. Possible values are {@link #SYNC_SELECTED_POSITION} or
* {@link #SYNC_FIRST_POSITION}.
*/
int mSyncMode;
/** Our height after the last layout. */
private int mLayoutHeight;
/** Sync based on the selected child. */
static final int SYNC_SELECTED_POSITION = 0;
/** Sync based on the first child displayed. */
static final int SYNC_FIRST_POSITION = 1;
/** Maximum amount of time to spend in {@link #findSyncPosition()}. */
static final int SYNC_MAX_DURATION_MILLIS = 100;
/**
* Indicates that this view is currently being laid out.
*/
boolean mInLayout = false;
/**
* The listener that receives notifications when an item is selected.
*/
OnItemSelectedListener mOnItemSelectedListener;
/**
* The listener that receives notifications when an item is clicked.
*/
OnItemClickListener mOnItemClickListener;
/**
* The listener that receives notifications when an item is long clicked.
*/
OnItemLongClickListener mOnItemLongClickListener;
/** True if the data has changed since the last layout. */
boolean mDataChanged;
/**
* The position within the adapter's data set of the item to select during the next layout.
*/
int mNextSelectedPosition = INVALID_POSITION;
/**
* The item id of the item to select during the next layout.
*/
long mNextSelectedRowId = INVALID_ROW_ID;
/**
* The position within the adapter's data set of the currently selected item.
*/
int mSelectedPosition = INVALID_POSITION;
/**
* The item id of the currently selected item.
*/
long mSelectedRowId = INVALID_ROW_ID;
/**
* View to show if there are no items to show.
*/
private View mEmptyView;
/**
* The number of items in the current adapter.
*/
int mItemCount;
/**
* The number of items in the adapter before a data changed event occurred.
*/
int mOldItemCount;
/**
* Represents an invalid position. All valid positions are in the range 0 to 1 less than the number of items in the current
* adapter.
*/
public static final int INVALID_POSITION = -1;
/** Represents an empty or invalid row id. */
public static final long INVALID_ROW_ID = Long.MIN_VALUE;
/** The last selected position we used when notifying. */
int mOldSelectedPosition = INVALID_POSITION;
/** The id of the last selected position we used when notifying. */
long mOldSelectedRowId = INVALID_ROW_ID;
/**
* Indicates what focusable state is requested when calling setFocusable(). In addition to this, this view has other criteria for
* actually determining the focusable state (such as whether its empty or the text filter is shown).
*
* @see #setFocusable(boolean)
* @see #checkFocus()
*/
private boolean mDesiredFocusableState;
/** The m desired focusable in touch mode state. */
private boolean mDesiredFocusableInTouchModeState;
/** The m selection notifier. */
private SelectionNotifier mSelectionNotifier;
/**
* When set to true, calls to requestLayout() will not propagate up the parent hierarchy. This is used to layout the children
* during a layout pass.
*/
boolean mBlockLayoutRequests = false;
/**
* Instantiates a new adapter view.
*
* @param context
* the context
*/
public AdapterView( Context context ) {
super( context );
}
/**
* Instantiates a new adapter view.
*
* @param context
* the context
* @param attrs
* the attrs
*/
public AdapterView( Context context, AttributeSet attrs ) {
super( context, attrs );
}
/**
* Instantiates a new adapter view.
*
* @param context
* the context
* @param attrs
* the attrs
* @param defStyle
* the def style
*/
public AdapterView( Context context, AttributeSet attrs, int defStyle ) {
super( context, attrs, defStyle );
}
/**
* Interface definition for a callback to be invoked when an item in this AdapterView has been clicked.
*
* @see OnItemClickEvent
*/
public interface OnItemClickListener {
/**
* Callback method to be invoked when an item in this AdapterView has been clicked.
* <p>
* Implementers can call getItemAtPosition(position) if they need to access the data associated with the selected item.
*
* @param parent
* The AdapterView where the click happened.
* @param view
* The view within the AdapterView that was clicked (this will be a view provided by the adapter)
* @param position
* The position of the view in the adapter.
* @param id
* The row id of the item that was clicked.
*/
void onItemClick( AdapterView<?> parent, View view, int position, long id );
}
/**
* Register a callback to be invoked when an item in this AdapterView has been clicked.
*
* @param listener
* The callback that will be invoked.
*/
public void setOnItemClickListener( OnItemClickListener listener ) {
mOnItemClickListener = listener;
}
/**
* Gets the on item click listener.
*
* @return The callback to be invoked with an item in this AdapterView has been clicked, or null id no callback has been set.
*/
public final OnItemClickListener getOnItemClickListener() {
return mOnItemClickListener;
}
/**
* Call the OnItemClickListener, if it is defined.
*
* @param view
* The view within the AdapterView that was clicked.
* @param position
* The position of the view in the adapter.
* @param id
* The row id of the item that was clicked.
* @return True if there was an assigned OnItemClickListener that was called, false otherwise is returned.
*/
public boolean performItemClick( View view, int position, long id ) {
if ( mOnItemClickListener != null ) {
playSoundEffect( SoundEffectConstants.CLICK );
if ( view != null ) {
view.sendAccessibilityEvent( AccessibilityEvent.TYPE_VIEW_CLICKED );
}
mOnItemClickListener.onItemClick( this, view, position, id );
return true;
}
return false;
}
/**
* Interface definition for a callback to be invoked when an item in this view has been clicked and held.
*
* @see OnItemLongClickEvent
*/
public interface OnItemLongClickListener {
/**
* Callback method to be invoked when an item in this view has been clicked and held.
*
* Implementers can call getItemAtPosition(position) if they need to access the data associated with the selected item.
*
* @param parent
* The AbsListView where the click happened
* @param view
* The view within the AbsListView that was clicked
* @param position
* The position of the view in the list
* @param id
* The row id of the item that was clicked
*
* @return true if the callback consumed the long click, false otherwise
*/
boolean onItemLongClick( AdapterView<?> parent, View view, int position, long id );
}
/**
* Register a callback to be invoked when an item in this AdapterView has been clicked and held.
*
* @param listener
* The callback that will run
*/
public void setOnItemLongClickListener( OnItemLongClickListener listener ) {
if ( !isLongClickable() ) {
setLongClickable( true );
}
mOnItemLongClickListener = listener;
}
/**
* Gets the on item long click listener.
*
* @return The callback to be invoked with an item in this AdapterView has been clicked and held, or null id no callback as been
* set.
*/
public final OnItemLongClickListener getOnItemLongClickListener() {
return mOnItemLongClickListener;
}
/**
* Interface definition for a callback to be invoked when an item in this view has been selected.
*
* @see OnItemSelectedEvent
*/
public interface OnItemSelectedListener {
/**
* <p>
* Callback method to be invoked when an item in this view has been selected. This callback is invoked only when the newly
* selected position is different from the previously selected position or if there was no selected item.
* </p>
*
* Impelmenters can call getItemAtPosition(position) if they need to access the data associated with the selected item.
*
* @param parent
* The AdapterView where the selection happened
* @param view
* The view within the AdapterView that was clicked
* @param position
* The position of the view in the adapter
* @param id
* The row id of the item that is selected
*/
void onItemSelected( AdapterView<?> parent, View view, int position, long id );
/**
* Callback method to be invoked when the selection disappears from this view. The selection can disappear for instance when
* touch is activated or when the adapter becomes empty.
*
* @param parent
* The AdapterView that now contains no selected item.
*/
void onNothingSelected( AdapterView<?> parent );
}
/**
* Register a callback to be invoked when an item in this AdapterView has been selected.
*
* @param listener
* The callback that will run
*/
public void setOnItemSelectedListener( OnItemSelectedListener listener ) {
mOnItemSelectedListener = listener;
}
/**
* Gets the on item selected listener.
*
* @return the on item selected listener
*/
public final OnItemSelectedListener getOnItemSelectedListener() {
return mOnItemSelectedListener;
}
/**
* Extra menu information provided to the.
*
* {@link android.view.View.OnCreateContextMenuListener#onCreateContextMenu(ContextMenu, View, ContextMenuInfo) } callback when a
* context menu is brought up for this AdapterView.
*/
public static class AdapterContextMenuInfo implements ContextMenu.ContextMenuInfo {
/**
* Instantiates a new adapter context menu info.
*
* @param targetView
* the target view
* @param position
* the position
* @param id
* the id
*/
public AdapterContextMenuInfo( View targetView, int position, long id ) {
this.targetView = targetView;
this.position = position;
this.id = id;
}
/**
* The child view for which the context menu is being displayed. This will be one of the children of this AdapterView.
*/
public View targetView;
/**
* The position in the adapter for which the context menu is being displayed.
*/
public int position;
/**
* The row id of the item for which the context menu is being displayed.
*/
public long id;
}
/**
* Returns the adapter currently associated with this widget.
*
* @return The adapter used to provide this view's content.
*/
public abstract T getAdapter();
/**
* Sets the adapter that provides the data and the views to represent the data in this widget.
*
* @param adapter
* The adapter to use to create this view's content.
*/
public abstract void setAdapter( T adapter );
/**
* This method is not supported and throws an UnsupportedOperationException when called.
*
* @param child
* Ignored.
*/
@Override
public void addView( View child ) {
throw new UnsupportedOperationException( "addView(View) is not supported in AdapterView" );
}
/**
* This method is not supported and throws an UnsupportedOperationException when called.
*
* @param child
* Ignored.
* @param index
* Ignored.
*/
@Override
public void addView( View child, int index ) {
throw new UnsupportedOperationException( "addView(View, int) is not supported in AdapterView" );
}
/**
* This method is not supported and throws an UnsupportedOperationException when called.
*
* @param child
* Ignored.
* @param params
* Ignored.
*/
@Override
public void addView( View child, LayoutParams params ) {
throw new UnsupportedOperationException( "addView(View, LayoutParams) " + "is not supported in AdapterView" );
}
/**
* This method is not supported and throws an UnsupportedOperationException when called.
*
* @param child
* Ignored.
* @param index
* Ignored.
* @param params
* Ignored.
*/
@Override
public void addView( View child, int index, LayoutParams params ) {
throw new UnsupportedOperationException( "addView(View, int, LayoutParams) " + "is not supported in AdapterView" );
}
/**
* This method is not supported and throws an UnsupportedOperationException when called.
*
* @param child
* Ignored.
*/
@Override
public void removeView( View child ) {
throw new UnsupportedOperationException( "removeView(View) is not supported in AdapterView" );
}
/**
* This method is not supported and throws an UnsupportedOperationException when called.
*
* @param index
* Ignored.
*/
@Override
public void removeViewAt( int index ) {
throw new UnsupportedOperationException( "removeViewAt(int) is not supported in AdapterView" );
}
/**
* This method is not supported and throws an UnsupportedOperationException when called.
*
*/
@Override
public void removeAllViews() {
throw new UnsupportedOperationException( "removeAllViews() is not supported in AdapterView" );
}
/*
* (non-Javadoc)
*
* @see android.view.ViewGroup#onLayout(boolean, int, int, int, int)
*/
@Override
protected void onLayout( boolean changed, int left, int top, int right, int bottom ) {
mLayoutHeight = getHeight();
}
/**
* Return the position of the currently selected item within the adapter's data set.
*
* @return int Position (starting at 0), or {@link #INVALID_POSITION} if there is nothing selected.
*/
@ViewDebug.CapturedViewProperty
public int getSelectedItemPosition() {
return mNextSelectedPosition;
}
/**
* Gets the selected item id.
*
* @return The id corresponding to the currently selected item, or {@link #INVALID_ROW_ID} if nothing is selected.
*/
@ViewDebug.CapturedViewProperty
public long getSelectedItemId() {
return mNextSelectedRowId;
}
/**
* Gets the selected view.
*
* @return The view corresponding to the currently selected item, or null if nothing is selected
*/
public abstract View getSelectedView();
/**
* Gets the selected item.
*
* @return The data corresponding to the currently selected item, or null if there is nothing selected.
*/
public Object getSelectedItem() {
T adapter = getAdapter();
int selection = getSelectedItemPosition();
if ( adapter != null && adapter.getCount() > 0 && selection >= 0 ) {
return adapter.getItem( selection );
} else {
return null;
}
}
/**
* Gets the count.
*
* @return The number of items owned by the Adapter associated with this AdapterView. (This is the number of data items, which
* may be larger than the number of visible views.)
*/
@ViewDebug.CapturedViewProperty
public int getCount() {
return mItemCount;
}
/**
* Get the position within the adapter's data set for the view, where view is a an adapter item or a descendant of an adapter
* item.
*
* @param view
* an adapter item, or a descendant of an adapter item. This must be visible in this AdapterView at the time of the
* call.
* @return the position within the adapter's data set of the view, or {@link #INVALID_POSITION} if the view does not correspond
* to a list item (or it is not currently visible).
*/
public int getPositionForView( View view ) {
View listItem = view;
try {
View v;
while ( !( v = (View) listItem.getParent() ).equals( this ) ) {
listItem = v;
}
} catch ( ClassCastException e ) {
// We made it up to the window without find this list view
return INVALID_POSITION;
}
// Search the children for the list item
final int childCount = getChildCount();
for ( int i = 0; i < childCount; i++ ) {
if ( getChildAt( i ).equals( listItem ) ) {
return mFirstPosition + i;
}
}
// Child not found!
return INVALID_POSITION;
}
/**
* Returns the position within the adapter's data set for the first item displayed on screen.
*
* @return The position within the adapter's data set
*/
public int getFirstVisiblePosition() {
return mFirstPosition;
}
/**
* Returns the position within the adapter's data set for the last item displayed on screen.
*
* @return The position within the adapter's data set
*/
public int getLastVisiblePosition() {
return mFirstPosition + getChildCount() - 1;
}
/**
* Sets the currently selected item. To support accessibility subclasses that override this method must invoke the overriden
* super method first.
*
* @param position
* Index (starting at 0) of the data item to be selected.
*/
public abstract void setSelection( int position );
/**
* Sets the view to show if the adapter is empty.
*
* @param emptyView
* the new empty view
*/
public void setEmptyView( View emptyView ) {
mEmptyView = emptyView;
final T adapter = getAdapter();
final boolean empty = ( ( adapter == null ) || adapter.isEmpty() );
updateEmptyStatus( empty );
}
/**
* When the current adapter is empty, the AdapterView can display a special view call the empty view. The empty view is used to
* provide feedback to the user that no data is available in this AdapterView.
*
* @return The view to show if the adapter is empty.
*/
public View getEmptyView() {
return mEmptyView;
}
/**
* Indicates whether this view is in filter mode. Filter mode can for instance be enabled by a user when typing on the keyboard.
*
* @return True if the view is in filter mode, false otherwise.
*/
boolean isInFilterMode() {
return false;
}
/*
* (non-Javadoc)
*
* @see android.view.View#setFocusable(boolean)
*/
@Override
public void setFocusable( boolean focusable ) {
final T adapter = getAdapter();
final boolean empty = adapter == null || adapter.getCount() == 0;
mDesiredFocusableState = focusable;
if ( !focusable ) {
mDesiredFocusableInTouchModeState = false;
}
super.setFocusable( focusable && ( !empty || isInFilterMode() ) );
}
/*
* (non-Javadoc)
*
* @see android.view.View#setFocusableInTouchMode(boolean)
*/
@Override
public void setFocusableInTouchMode( boolean focusable ) {
final T adapter = getAdapter();
final boolean empty = adapter == null || adapter.getCount() == 0;
mDesiredFocusableInTouchModeState = focusable;
if ( focusable ) {
mDesiredFocusableState = true;
}
super.setFocusableInTouchMode( focusable && ( !empty || isInFilterMode() ) );
}
/**
* Check focus.
*/
void checkFocus() {
final T adapter = getAdapter();
final boolean empty = adapter == null || adapter.getCount() == 0;
final boolean focusable = !empty || isInFilterMode();
// The order in which we set focusable in touch mode/focusable may matter
// for the client, see View.setFocusableInTouchMode() comments for more
// details
super.setFocusableInTouchMode( focusable && mDesiredFocusableInTouchModeState );
super.setFocusable( focusable && mDesiredFocusableState );
if ( mEmptyView != null ) {
updateEmptyStatus( ( adapter == null ) || adapter.isEmpty() );
}
}
/**
* Update the status of the list based on the empty parameter. If empty is true and we have an empty view, display it. In all the
* other cases, make sure that the listview is VISIBLE and that the empty view is GONE (if it's not null).
*
* @param empty
* the empty
*/
private void updateEmptyStatus( boolean empty ) {
if ( isInFilterMode() ) {
empty = false;
}
if ( empty ) {
if ( mEmptyView != null ) {
mEmptyView.setVisibility( View.VISIBLE );
setVisibility( View.GONE );
} else {
// If the caller just removed our empty view, make sure the list view is visible
setVisibility( View.VISIBLE );
}
// We are now GONE, so pending layouts will not be dispatched.
// Force one here to make sure that the state of the list matches
// the state of the adapter.
if ( mDataChanged ) {
this.onLayout( false, getLeft(), getTop(), getRight(), getBottom() );
}
} else {
if ( mEmptyView != null ) mEmptyView.setVisibility( View.GONE );
setVisibility( View.VISIBLE );
}
}
/**
* Gets the data associated with the specified position in the list.
*
* @param position
* Which data to get
* @return The data associated with the specified position in the list
*/
public Object getItemAtPosition( int position ) {
T adapter = getAdapter();
return ( adapter == null || position < 0 ) ? null : adapter.getItem( position );
}
/**
* Gets the item id at position.
*
* @param position
* the position
* @return the item id at position
*/
public long getItemIdAtPosition( int position ) {
T adapter = getAdapter();
return ( adapter == null || position < 0 ) ? INVALID_ROW_ID : adapter.getItemId( position );
}
/*
* (non-Javadoc)
*
* @see android.view.View#setOnClickListener(android.view.View.OnClickListener)
*/
@Override
public void setOnClickListener( OnClickListener l ) {
throw new RuntimeException( "Don't call setOnClickListener for an AdapterView. "
+ "You probably want setOnItemClickListener instead" );
}
/**
* Override to prevent freezing of any views created by the adapter.
*
* @param container
* the container
*/
@Override
protected void dispatchSaveInstanceState( SparseArray<Parcelable> container ) {
dispatchFreezeSelfOnly( container );
}
/**
* Override to prevent thawing of any views created by the adapter.
*
* @param container
* the container
*/
@Override
protected void dispatchRestoreInstanceState( SparseArray<Parcelable> container ) {
dispatchThawSelfOnly( container );
}
/**
* An asynchronous update interface for receiving notifications about AdapterDataSet information as the AdapterDataSet is
* constructed.
*/
class AdapterDataSetObserver extends DataSetObserver {
/** The m instance state. */
private Parcelable mInstanceState = null;
/*
* (non-Javadoc)
*
* @see android.database.DataSetObserver#onChanged()
*/
@Override
public void onChanged() {
mDataChanged = true;
mOldItemCount = mItemCount;
mItemCount = getAdapter().getCount();
// Detect the case where a cursor that was previously invalidated has
// been repopulated with new data.
if ( AdapterView.this.getAdapter().hasStableIds() && mInstanceState != null && mOldItemCount == 0 && mItemCount > 0 ) {
AdapterView.this.onRestoreInstanceState( mInstanceState );
mInstanceState = null;
} else {
rememberSyncState();
}
checkFocus();
requestLayout();
}
/*
* (non-Javadoc)
*
* @see android.database.DataSetObserver#onInvalidated()
*/
@Override
public void onInvalidated() {
mDataChanged = true;
if ( AdapterView.this.getAdapter().hasStableIds() ) {
// Remember the current state for the case where our hosting activity is being
// stopped and later restarted
mInstanceState = AdapterView.this.onSaveInstanceState();
}
// Data is invalid so we should reset our state
mOldItemCount = mItemCount;
mItemCount = 0;
mSelectedPosition = INVALID_POSITION;
mSelectedRowId = INVALID_ROW_ID;
mNextSelectedPosition = INVALID_POSITION;
mNextSelectedRowId = INVALID_ROW_ID;
mNeedSync = false;
checkFocus();
requestLayout();
}
/**
* This method is called when information about an AdapterDataSet which was previously requested using an asynchronous
* interface becomes available.
*/
public void clearSavedState() {
mInstanceState = null;
}
}
/*
* (non-Javadoc)
*
* @see android.view.View#onDetachedFromWindow()
*/
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
removeCallbacks( mSelectionNotifier );
}
/**
* The Class SelectionNotifier.
*/
private class SelectionNotifier implements Runnable {
/*
* (non-Javadoc)
*
* @see java.lang.Runnable#run()
*/
public void run() {
if ( mDataChanged ) {
// Data has changed between when this SelectionNotifier
// was posted and now. We need to wait until the AdapterView
// has been synched to the new data.
if ( getAdapter() != null ) {
post( this );
}
} else {
fireOnSelected();
}
}
}
/**
* Selection changed.
*/
void selectionChanged() {
if ( mOnItemSelectedListener != null ) {
if ( mInLayout || mBlockLayoutRequests ) {
// If we are in a layout traversal, defer notification
// by posting. This ensures that the view tree is
// in a consistent state and is able to accomodate
// new layout or invalidate requests.
if ( mSelectionNotifier == null ) {
mSelectionNotifier = new SelectionNotifier();
}
post( mSelectionNotifier );
} else {
fireOnSelected();
}
}
// we fire selection events here not in View
if ( mSelectedPosition != ListView.INVALID_POSITION && isShown() && !isInTouchMode() ) {
sendAccessibilityEvent( AccessibilityEvent.TYPE_VIEW_SELECTED );
}
}
/**
* Fire on selected.
*/
private void fireOnSelected() {
if ( mOnItemSelectedListener == null ) return;
int selection = this.getSelectedItemPosition();
if ( selection >= 0 ) {
View v = getSelectedView();
mOnItemSelectedListener.onItemSelected( this, v, selection, getAdapter().getItemId( selection ) );
} else {
mOnItemSelectedListener.onNothingSelected( this );
}
}
/*
* (non-Javadoc)
*
* @see android.view.View#dispatchPopulateAccessibilityEvent(android.view.accessibility.AccessibilityEvent)
*/
@Override
public boolean dispatchPopulateAccessibilityEvent( AccessibilityEvent event ) {
View selectedView = getSelectedView();
if ( selectedView != null && selectedView.getVisibility() == VISIBLE
&& selectedView.dispatchPopulateAccessibilityEvent( event ) ) {
return true;
}
return false;
}
/**
* Checks if is scrollable for accessibility.
*
* @return true, if is scrollable for accessibility
*/
private boolean isScrollableForAccessibility() {
T adapter = getAdapter();
if ( adapter != null ) {
final int itemCount = adapter.getCount();
return itemCount > 0 && ( getFirstVisiblePosition() > 0 || getLastVisiblePosition() < itemCount - 1 );
}
return false;
}
/*
* (non-Javadoc)
*
* @see android.view.ViewGroup#canAnimate()
*/
@Override
protected boolean canAnimate() {
return super.canAnimate() && mItemCount > 0;
}
/**
* Handle data changed.
*/
void handleDataChanged() {
final int count = mItemCount;
boolean found = false;
if ( count > 0 ) {
int newPos;
// Find the row we are supposed to sync to
if ( mNeedSync ) {
// Update this first, since setNextSelectedPositionInt inspects
// it
mNeedSync = false;
// See if we can find a position in the new data with the same
// id as the old selection
newPos = findSyncPosition();
if ( newPos >= 0 ) {
// Verify that new selection is selectable
int selectablePos = lookForSelectablePosition( newPos, true );
if ( selectablePos == newPos ) {
// Same row id is selected
setNextSelectedPositionInt( newPos );
found = true;
}
}
}
if ( !found ) {
// Try to use the same position if we can't find matching data
newPos = getSelectedItemPosition();
// Pin position to the available range
if ( newPos >= count ) {
newPos = count - 1;
}
if ( newPos < 0 ) {
newPos = 0;
}
// Make sure we select something selectable -- first look down
int selectablePos = lookForSelectablePosition( newPos, true );
if ( selectablePos < 0 ) {
// Looking down didn't work -- try looking up
selectablePos = lookForSelectablePosition( newPos, false );
}
if ( selectablePos >= 0 ) {
setNextSelectedPositionInt( selectablePos );
checkSelectionChanged();
found = true;
}
}
}
if ( !found ) {
// Nothing is selected
mSelectedPosition = INVALID_POSITION;
mSelectedRowId = INVALID_ROW_ID;
mNextSelectedPosition = INVALID_POSITION;
mNextSelectedRowId = INVALID_ROW_ID;
mNeedSync = false;
checkSelectionChanged();
}
}
/**
* Check selection changed.
*/
void checkSelectionChanged() {
if ( ( mSelectedPosition != mOldSelectedPosition ) || ( mSelectedRowId != mOldSelectedRowId ) ) {
selectionChanged();
mOldSelectedPosition = mSelectedPosition;
mOldSelectedRowId = mSelectedRowId;
}
}
/**
* Searches the adapter for a position matching mSyncRowId. The search starts at mSyncPosition and then alternates between moving
* up and moving down until 1) we find the right position, or 2) we run out of time, or 3) we have looked at every position
*
* @return Position of the row that matches mSyncRowId, or {@link #INVALID_POSITION} if it can't be found
*/
int findSyncPosition() {
int count = mItemCount;
if ( count == 0 ) {
return INVALID_POSITION;
}
long idToMatch = mSyncRowId;
int seed = mSyncPosition;
// If there isn't a selection don't hunt for it
if ( idToMatch == INVALID_ROW_ID ) {
return INVALID_POSITION;
}
// Pin seed to reasonable values
seed = Math.max( 0, seed );
seed = Math.min( count - 1, seed );
long endTime = SystemClock.uptimeMillis() + SYNC_MAX_DURATION_MILLIS;
long rowId;
// first position scanned so far
int first = seed;
// last position scanned so far
int last = seed;
// True if we should move down on the next iteration
boolean next = false;
// True when we have looked at the first item in the data
boolean hitFirst;
// True when we have looked at the last item in the data
boolean hitLast;
// Get the item ID locally (instead of getItemIdAtPosition), so
// we need the adapter
T adapter = getAdapter();
if ( adapter == null ) {
return INVALID_POSITION;
}
while ( SystemClock.uptimeMillis() <= endTime ) {
rowId = adapter.getItemId( seed );
if ( rowId == idToMatch ) {
// Found it!
return seed;
}
hitLast = last == count - 1;
hitFirst = first == 0;
if ( hitLast && hitFirst ) {
// Looked at everything
break;
}
if ( hitFirst || ( next && !hitLast ) ) {
// Either we hit the top, or we are trying to move down
last++;
seed = last;
// Try going up next time
next = false;
} else if ( hitLast || ( !next && !hitFirst ) ) {
// Either we hit the bottom, or we are trying to move up
first--;
seed = first;
// Try going down next time
next = true;
}
}
return INVALID_POSITION;
}
/**
* Find a position that can be selected (i.e., is not a separator).
*
* @param position
* The starting position to look at.
* @param lookDown
* Whether to look down for other positions.
* @return The next selectable position starting at position and then searching either up or down. Returns
* {@link #INVALID_POSITION} if nothing can be found.
*/
int lookForSelectablePosition( int position, boolean lookDown ) {
return position;
}
/**
* Utility to keep mSelectedPosition and mSelectedRowId in sync.
*
* @param position
* Our current position
*/
void setSelectedPositionInt( int position ) {
mSelectedPosition = position;
mSelectedRowId = getItemIdAtPosition( position );
}
/**
* Utility to keep mNextSelectedPosition and mNextSelectedRowId in sync.
*
* @param position
* Intended value for mSelectedPosition the next time we go through layout
*/
void setNextSelectedPositionInt( int position ) {
mNextSelectedPosition = position;
mNextSelectedRowId = getItemIdAtPosition( position );
// If we are trying to sync to the selection, update that too
if ( mNeedSync && mSyncMode == SYNC_SELECTED_POSITION && position >= 0 ) {
mSyncPosition = position;
mSyncRowId = mNextSelectedRowId;
}
}
/**
* Remember enough information to restore the screen state when the data has changed.
*
*/
void rememberSyncState() {
if ( getChildCount() > 0 ) {
mNeedSync = true;
mSyncHeight = mLayoutHeight;
if ( mSelectedPosition >= 0 ) {
// Sync the selection state
View v = getChildAt( mSelectedPosition - mFirstPosition );
mSyncRowId = mNextSelectedRowId;
mSyncPosition = mNextSelectedPosition;
if ( v != null ) {
mSpecificTop = v.getTop();
}
mSyncMode = SYNC_SELECTED_POSITION;
} else {
// Sync the based on the offset of the first view
View v = getChildAt( 0 );
T adapter = getAdapter();
if ( mFirstPosition >= 0 && mFirstPosition < adapter.getCount() ) {
mSyncRowId = adapter.getItemId( mFirstPosition );
} else {
mSyncRowId = NO_ID;
}
mSyncPosition = mFirstPosition;
if ( v != null ) {
mSpecificTop = v.getTop();
}
mSyncMode = SYNC_FIRST_POSITION;
}
}
}
}