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/*
* Copyright (C) 2018 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.dialer.speeddial.draghelper;
import android.graphics.Canvas;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.ViewHolder;
import android.support.v7.widget.helper.ItemTouchHelper;
/** {@link ItemTouchHelper} for Speed Dial favorite contacts. */
public class SpeedDialItemTouchHelperCallback extends ItemTouchHelper.Callback {
private final ItemTouchHelperAdapter adapter;
// When dragged item is in removeView, onMove() and onChildDraw() are called in turn. This
// behavior changes when dragged item entering/leaving removeView. The boolean field
// movedOverRemoveView is for onMove() and onChildDraw() to flip.
private boolean movedOverRemoveView;
private boolean inRemoveView;
public SpeedDialItemTouchHelperCallback(ItemTouchHelperAdapter adapter) {
this.adapter = adapter;
}
@Override
public boolean isLongPressDragEnabled() {
// We'll manually call ItemTouchHelper#startDrag
return false;
}
@Override
public boolean isItemViewSwipeEnabled() {
// We don't want to enable swiping
return false;
}
@Override
public boolean canDropOver(
@NonNull RecyclerView recyclerView, @NonNull ViewHolder current, @NonNull ViewHolder target) {
return adapter.canDropOver(target);
}
@Override
public int getMovementFlags(@NonNull RecyclerView recyclerView, @NonNull ViewHolder viewHolder) {
if (!adapter.canDropOver(viewHolder)) {
return makeMovementFlags(0, 0);
}
int dragFlags =
ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.START | ItemTouchHelper.END;
return makeMovementFlags(dragFlags, /* swipeFlags */ 0);
}
@Override
public boolean onMove(
@NonNull RecyclerView recyclerView,
@NonNull ViewHolder viewHolder,
@NonNull ViewHolder target) {
if (target.getItemViewType() == 0) { // 0 for RowType.REMOVE_VIEW
movedOverRemoveView = true;
if (!inRemoveView) {
// onMove() first called
adapter.enterRemoveView();
inRemoveView = true;
}
return false;
} else if (inRemoveView) {
// Move out of removeView fast
inRemoveView = false;
movedOverRemoveView = false;
adapter.leaveRemoveView();
}
adapter.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
return true;
}
@Override
public void onChildDraw(
@NonNull Canvas canvas,
@NonNull RecyclerView recyclerView,
@NonNull ViewHolder viewHolder,
float dx,
float dy,
int i,
boolean isCurrentlyActive) {
if (inRemoveView) {
if (!isCurrentlyActive) {
// View animating back to its original state, which means drop in this case
inRemoveView = false;
adapter.dropOnRemoveView(viewHolder);
}
if (!movedOverRemoveView) {
// when the view is over a droppable target, onMove() will be called before onChildDraw()
// thus if onMove() is not called, it is not over a droppable target.
inRemoveView = false;
adapter.leaveRemoveView();
}
}
movedOverRemoveView = false;
super.onChildDraw(canvas, recyclerView, viewHolder, dx, dy, i, isCurrentlyActive);
}
@Override
public void onSelectedChanged(@Nullable ViewHolder viewHolder, int actionState) {
super.onSelectedChanged(viewHolder, actionState);
adapter.onSelectedChanged(viewHolder, actionState);
}
@Override
public void onSwiped(@NonNull ViewHolder viewHolder, int direction) {
// No-op since we don't support swiping
}
/** RecyclerView adapters interested in drag and drop should implement this interface. */
public interface ItemTouchHelperAdapter {
void onItemMove(int fromPosition, int toPosition);
boolean canDropOver(ViewHolder target);
void onSelectedChanged(@Nullable ViewHolder viewHolder, int actionState);
void enterRemoveView();
void leaveRemoveView();
void dropOnRemoveView(ViewHolder fromViewHolder);
}
}
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