package com.wpc.library.recyclerviewhelper;
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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.RecyclerView;
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import androidx.recyclerview.widget.StaggeredGridLayoutManager;
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import androidx.recyclerview.widget.ItemTouchHelper;
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/**
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* ItemDragHelperCallback
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* Created by YoKeyword on 15/12/29.
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*/
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public class ItemDragHelperCallback extends ItemTouchHelper.Callback {
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private int noMovePosition;
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public ItemDragHelperCallback(int noMovePosition) {
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this.noMovePosition = noMovePosition;
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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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int fromPosition = viewHolder.getAdapterPosition();
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if (fromPosition < noMovePosition)
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return 0;
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int dragFlags;
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RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
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if (manager instanceof GridLayoutManager || manager instanceof StaggeredGridLayoutManager) {
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dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
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} else {
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dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
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}
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// 如果想支持滑动(删除)操作, swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END
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int swipeFlags = 0;
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return makeMovementFlags(dragFlags, swipeFlags);
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}
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@Override
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public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
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// 不同Type之间不可移动
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if (viewHolder.getItemViewType() != target.getItemViewType()) {
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return false;
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}
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if (recyclerView.getAdapter() instanceof OnItemMoveListener && direction != 0) {
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OnItemMoveListener listener = ((OnItemMoveListener) recyclerView.getAdapter());
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listener.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition(), direction);
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direction = 0;
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}
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return true;
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}
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int direction = 0;//1、上拉；2、下滑；3、左滑；4、右滑
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float itemWidth = 0;
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float itemHeight = 0;
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@Override
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public void onChildDrawOver(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
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super.onChildDrawOver(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
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int fromPosition = viewHolder.getAdapterPosition();
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if (itemWidth == 0) {
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//获取单个Item宽度
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itemWidth = recyclerView.getChildAt(fromPosition).getMeasuredWidth() / 2;
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}
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if (itemHeight == 0) {
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//获取单个Item高度
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itemHeight = recyclerView.getChildAt(fromPosition).getMeasuredHeight() / 2;
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}
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// Log.e("mResult", "scrollX:" + itemWidth + "---scrollY:" + itemHeight);
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if (dX < 0 && Math.abs(dX) >= itemWidth) {
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direction = 3;
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} else if (dX > 0 && Math.abs(dX) >= itemWidth) {
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direction = 4;
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} else if (dY < 0 && Math.abs(dY) >= itemHeight) {
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direction = 1;
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} else if (dY > 0 && Math.abs(dY) >= itemHeight) {
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direction = 2;
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} else {
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direction = 0;
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}
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if (Math.abs(dX) >= itemWidth || Math.abs(dY) >= itemHeight) {
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onMove(recyclerView, viewHolder, viewHolder);
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}
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}
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@Override
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public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
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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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// 不在闲置状态
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if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
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if (viewHolder instanceof OnDragVHListener) {
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OnDragVHListener itemViewHolder = (OnDragVHListener) 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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}
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@Override
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public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
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if (viewHolder instanceof OnDragVHListener) {
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OnDragVHListener itemViewHolder = (OnDragVHListener) viewHolder;
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itemViewHolder.onItemFinish();
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}
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super.clearView(recyclerView, viewHolder);
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}
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@Override
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public boolean isLongPressDragEnabled() {
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// 不支持长按拖拽功能 手动控制
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return false;
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}
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@Override
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public boolean isItemViewSwipeEnabled() {
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// 不支持滑动功能
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return false;
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}
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}
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