/*
*
* * Copyright 2015. Appsi Mobile
* *
* * 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.mobeta.android.dslv;
import android.content.Context;
import android.database.Cursor;
import android.support.v4.widget.CursorAdapter;
import android.util.SparseIntArray;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
/**
* A subclass of {@link android.widget.CursorAdapter} that provides
* reordering of the elements in the Cursor based on completed
* drag-sort operations. The reordering is a simple mapping of
* list positions into Cursor positions (the Cursor is unchanged).
* To persist changes made by drag-sorts, one can retrieve the
* mapping with the {@link #getCursorPositions()} method, which
* returns the reordered list of Cursor positions.
* <p/>
* An instance of this class is passed
* to {@link com.mobeta.android.dslv.DragSortListView#setAdapter(ListAdapter)} and, since
* this class implements the {@link com.mobeta.android.dslv.DragSortListView.DragSortListener}
* interface, it is automatically set as the DragSortListener for
* the DragSortListView instance.
*/
public abstract class DragSortCursorAdapter extends CursorAdapter
implements DragSortListView.DragSortListener {
public static final int REMOVED = -1;
/**
* Key is ListView position, value is Cursor position
*/
private SparseIntArray mListMapping = new SparseIntArray();
private ArrayList<Integer> mRemovedCursorPositions = new ArrayList<Integer>();
public DragSortCursorAdapter(Context context, Cursor c) {
super(context, c);
}
public DragSortCursorAdapter(Context context, Cursor c, boolean autoRequery) {
super(context, c, autoRequery);
}
public DragSortCursorAdapter(Context context, Cursor c, int flags) {
super(context, c, flags);
}
/**
* Swaps Cursor and clears list-Cursor mapping.
*
* @see android.widget.CursorAdapter#swapCursor(android.database.Cursor)
*/
@Override
public Cursor swapCursor(Cursor newCursor) {
Cursor old = super.swapCursor(newCursor);
resetMappings();
return old;
}
/**
* Changes Cursor and clears list-Cursor mapping.
*
* @see android.widget.CursorAdapter#changeCursor(android.database.Cursor)
*/
@Override
public void changeCursor(Cursor cursor) {
super.changeCursor(cursor);
resetMappings();
}
/**
* Resets list-cursor mapping.
*/
public void reset() {
resetMappings();
notifyDataSetChanged();
}
private void resetMappings() {
mListMapping.clear();
mRemovedCursorPositions.clear();
}
@Override
public Object getItem(int position) {
return super.getItem(mListMapping.get(position, position));
}
@Override
public long getItemId(int position) {
return super.getItemId(mListMapping.get(position, position));
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
return super.getDropDownView(mListMapping.get(position, position), convertView, parent);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
return super.getView(mListMapping.get(position, position), convertView, parent);
}
/**
* On drop, this updates the mapping between Cursor positions
* and ListView positions. The Cursor is unchanged. Retrieve
* the current mapping with {@link getCursorPositions()}.
*
* @see com.mobeta.android.dslv.DragSortListView.DropListener#drop(int, int)
*/
@Override
public void drop(int from, int to) {
if (from != to) {
int cursorFrom = mListMapping.get(from, from);
if (from > to) {
for (int i = from; i > to; --i) {
mListMapping.put(i, mListMapping.get(i - 1, i - 1));
}
} else {
for (int i = from; i < to; ++i) {
mListMapping.put(i, mListMapping.get(i + 1, i + 1));
}
}
mListMapping.put(to, cursorFrom);
cleanMapping();
notifyDataSetChanged();
}
}
/**
* On remove, this updates the mapping between Cursor positions
* and ListView positions. The Cursor is unchanged. Retrieve
* the current mapping with {@link getCursorPositions()}.
*
* @see com.mobeta.android.dslv.DragSortListView.RemoveListener#remove(int)
*/
@Override
public void remove(int which) {
int cursorPos = mListMapping.get(which, which);
if (!mRemovedCursorPositions.contains(cursorPos)) {
mRemovedCursorPositions.add(cursorPos);
}
int newCount = getCount();
for (int i = which; i < newCount; ++i) {
mListMapping.put(i, mListMapping.get(i + 1, i + 1));
}
mListMapping.delete(newCount);
cleanMapping();
notifyDataSetChanged();
}
/**
* Does nothing. Just completes DragSortListener interface.
*/
@Override
public void drag(int from, int to) {
// do nothing
}
/**
* Remove unnecessary mappings from sparse array.
*/
private void cleanMapping() {
ArrayList<Integer> toRemove = null;
int size = mListMapping.size();
for (int i = 0; i < size; ++i) {
if (mListMapping.keyAt(i) == mListMapping.valueAt(i)) {
if (toRemove == null) {
toRemove = new ArrayList<>();
}
toRemove.add(mListMapping.keyAt(i));
}
}
if (toRemove != null) {
size = toRemove.size();
for (int i = 0; i < size; ++i) {
mListMapping.delete(toRemove.get(i));
}
}
}
@Override
public int getCount() {
return super.getCount() - mRemovedCursorPositions.size();
}
/**
* Get the Cursor position mapped to by the provided list position
* (given all previously handled drag-sort
* operations).
*
* @param position List position
*
* @return The mapped-to Cursor position
*/
public int getCursorPosition(int position) {
return mListMapping.get(position, position);
}
/**
* Get the current order of Cursor positions presented by the
* list.
*/
public ArrayList<Integer> getCursorPositions() {
ArrayList<Integer> result = new ArrayList<Integer>();
for (int i = 0; i < getCount(); ++i) {
result.add(mListMapping.get(i, i));
}
return result;
}
/**
* Get the list position mapped to by the provided Cursor position.
* If the provided Cursor position has been removed by a drag-sort,
* this returns {@link #REMOVED}.
*
* @param cursorPosition A Cursor position
*
* @return The mapped-to list position or REMOVED
*/
public int getListPosition(int cursorPosition) {
if (mRemovedCursorPositions.contains(cursorPosition)) {
return REMOVED;
}
int index = mListMapping.indexOfValue(cursorPosition);
if (index < 0) {
return cursorPosition;
} else {
return mListMapping.keyAt(index);
}
}
}