/*
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* Copyright (C) 2015 Paul Burke
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.ypx.imagepicker.helper.recyclerviewitemhelper;
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import android.graphics.Canvas;
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import androidx.recyclerview.widget.GridLayoutManager;
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import androidx.recyclerview.widget.ItemTouchHelper;
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import androidx.recyclerview.widget.LinearLayoutManager;
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import androidx.recyclerview.widget.RecyclerView;
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/**
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* An implementation of {@link ItemTouchHelper.Callback} that enables basic drag & drop and
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* swipe-to-dismiss. Drag events are automatically started by an item long-press.<br/>
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* </br/>
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* Expects the <code>RecyclerView.Adapter</code> to listen for {@link
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* ItemTouchHelperAdapter} callbacks and the <code>RecyclerView.ViewHolder</code> to implement
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* {@link ItemTouchHelperViewHolder}.
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*
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* @author Paul Burke (ipaulpro)
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*/
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public class SimpleItemTouchHelperCallback extends ItemTouchHelper.Callback {
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public static final float ALPHA_FULL = 1.0f;
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private boolean moveFreely = false;
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private boolean lastActive = false;
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// 移动时，item 的放大系数
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private float moveScaleFactor = 1.1f;
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private final ItemTouchHelperAdapter mAdapter;
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private OnSelectChangedListener mOnSelectChangedListener;
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public SimpleItemTouchHelperCallback(ItemTouchHelperAdapter adapter) {
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mAdapter = adapter;
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}
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public void setOnSelectChangedListener(OnSelectChangedListener mOnSelectChangedListener) {
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this.mOnSelectChangedListener = mOnSelectChangedListener;
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}
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public void setMoveScaleFactor(float moveScaleFactor) {
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this.moveScaleFactor = moveScaleFactor;
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}
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@Override
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public boolean isItemViewSwipeEnabled() {
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return mAdapter.isItemViewSwipeEnabled();
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}
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public interface OnSelectChangedListener {
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/**
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* @param viewHolder
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* @param dX
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* @param dY
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* @param actionState
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* @param isCurrentlyActive
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*/
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void onSelectedChanged(RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive);
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/**
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* @param viewHolder
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* @param actionState
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*/
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void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState);
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}
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@Override
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public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
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// Set movement flags based on the layout manager
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if (moveFreely) {
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final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
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final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
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return makeMovementFlags(dragFlags, swipeFlags);
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} else if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
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final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
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final int swipeFlags = 0;
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return makeMovementFlags(dragFlags, swipeFlags);
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} else if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {
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LinearLayoutManager linear = (LinearLayoutManager) recyclerView.getLayoutManager();
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if (linear.getOrientation() == RecyclerView.HORIZONTAL) {
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final int dragFlags = ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
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final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
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return makeMovementFlags(dragFlags, swipeFlags);
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} else {
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final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
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final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
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return makeMovementFlags(dragFlags, swipeFlags);
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}
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} else {
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final int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
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final int swipeFlags = ItemTouchHelper.ACTION_STATE_IDLE;
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return makeMovementFlags(dragFlags, swipeFlags);
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}
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}
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@Override
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public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder source, RecyclerView.ViewHolder target) {
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if (source.getItemViewType() != target.getItemViewType()) {
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return false;
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}
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// Notify the adapter of the move
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mAdapter.onItemMove(source.getAdapterPosition(), target.getAdapterPosition());
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return true;
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}
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@Override
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public void onMoved(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, int fromPos, RecyclerView.ViewHolder target, int toPos, int x, int y) {
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super.onMoved(recyclerView, viewHolder, fromPos, target, toPos, x, y);
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viewHolder.itemView.setAlpha(1f);
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target.itemView.setAlpha(1f);
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}
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@Override
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public void onSwiped(RecyclerView.ViewHolder viewHolder, int i) {
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// Notify the adapter of the dismissal
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mAdapter.onItemDismiss(viewHolder.getAdapterPosition());
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}
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@Override
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public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
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if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
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// Fade out the view as it is swiped out of the parent's bounds
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final float alpha = ALPHA_FULL - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
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viewHolder.itemView.setAlpha(alpha);
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viewHolder.itemView.setTranslationX(dX);
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} else if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
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if (isCurrentlyActive) {
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viewHolder.itemView.setAlpha(0.5f);
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viewHolder.itemView.setScaleX(moveScaleFactor);
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viewHolder.itemView.setScaleY(moveScaleFactor);
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} else {
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viewHolder.itemView.setAlpha(1f);
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viewHolder.itemView.setScaleX(1f);
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viewHolder.itemView.setScaleY(1f);
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}
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super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
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} else {
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super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
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}
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// 从拖动到释放的过程
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if (null != mOnSelectChangedListener && !isCurrentlyActive && lastActive) {
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mOnSelectChangedListener.onSelectedChanged(viewHolder, dX, dY, actionState, isCurrentlyActive);
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}
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lastActive = isCurrentlyActive;
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}
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@Override
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public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
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// We only want the active item to change
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if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
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if (viewHolder instanceof ItemTouchHelperViewHolder) {
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// Let the view holder know that this item is being moved or dragged
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ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;
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itemViewHolder.onItemSelected();
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}
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}
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super.onSelectedChanged(viewHolder, actionState);
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if (null != mOnSelectChangedListener) {
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mOnSelectChangedListener.onSelectedChanged(viewHolder, actionState);
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}
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}
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@Override
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public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
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super.clearView(recyclerView, viewHolder);
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viewHolder.itemView.setAlpha(ALPHA_FULL);
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if (viewHolder instanceof ItemTouchHelperViewHolder) {
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// Tell the view holder it's time to restore the idle state
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ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;
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itemViewHolder.onItemClear();
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}
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}
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public void setMoveFreely(boolean moveFreely) {
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this.moveFreely = moveFreely;
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}
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}
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