Question

我正在进行拖放操作，现在正像启动器应用程序一样实现删除功能。我在选择回收商项目时可以看到删除图像，但无法通过拖放删除图像来删除回收商品。我正在使用Itemtouchhelperadapter和集合来选择和拖动回收物品。

    public RecyclerListAdapter(Context context, OnStartDragListener dragStartListener) {
    mDragStartListener = dragStartListener;
    mItems.addAll(Arrays.asList(context.getResources().getStringArray(R.array.dummy_items)));
}

@Override
public ItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    v = parent;
    trashView = (ImageView)v.getRootView().findViewById(R.id.main_trash);
    trashView.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent motionEvent) {
            Log.v("inside","ontouch");
            return false;
        }
    });
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_main, parent, false);
    ItemViewHolder itemViewHolder = new ItemViewHolder(view);
    return itemViewHolder;
}

@Override
public void onBindViewHolder(final ItemViewHolder holder, int position) {
    holder.textView.setText(mItems.get(position));

    // Start a drag whenever the handle view it touched
    holder.handleView.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (MotionEventCompat.getActionMasked(event) == MotionEvent.ACTION_DOWN) {
                mDragStartListener.onStartDrag(holder);
            }
            return false;
        }
    });
}

@Override
public void onItemDismiss(int position) {
    mItems.remove(position);
    notifyItemRemoved(position);
}

@Override
public boolean onItemMove(int fromPosition, int toPosition) {
    Collections.swap(mItems, fromPosition, toPosition);
    notifyItemMoved(fromPosition, toPosition);
    return true;
}

@Override
public int getItemCount() {
    return mItems.size();
}

public static class ItemViewHolder extends RecyclerView.ViewHolder implements
        ItemTouchHelperViewHolder {

    public final TextView textView;
    public final ImageView handleView;
    ImageView trashView;

    public ItemViewHolder(View itemView) {
        super(itemView);
        textView = (TextView) itemView.findViewById(R.id.text);
        handleView = (ImageView) itemView.findViewById(R.id.handle);
    }

    @Override
    public void onItemSelected() {
        trashView = (ImageView)v.getRootView().findViewById(R.id.main_trash);
        trashView.setVisibility(View.VISIBLE);
        itemView.setBackgroundColor(Color.LTGRAY);
        TextView tv = (TextView)itemView.findViewById(R.id.text);
        selectedText = tv.getText().toString();
    }

    @Override
    public void onItemClear() {
        ((ImageView)v.getRootView().findViewById(R.id.main_trash)).setVisibility(View.GONE);
        itemView.setBackgroundColor(0);
    }
}

Answer 1

由于您的代码充满了反复试验，因此您应该将其从任何不必要的内容中清除。

首先，您需要CoordinatorLayout包装现有布局，为其指定Id，然后在Activity/Fragment中对其进行初始化，同时实施View.OnDragListener并实施其所需方法。稍后会详细介绍。：）

其次，通话设置onDragListener：

    coordinatorLayout.setOnDragListener(this);

将implements View.OnLongClickListener添加到Adapter，按照以下方式实施所需的方法：

@Override
public boolean onLongClick(View v) {
    v.startDrag(ClipData.newPlainText("label", v.getTag().toString()), new View.DragShadowBuilder(v), null, 0);
    return true;
}

在tag中设置onLongClickListener和onBindViewHolder：

@Override
public void onBindViewHolder(CustomHolder holder, int position) {
    holder.itemView.setTag(position);
    holder.itemView.setOnLongClickListener(this); 
}

以下是onDrag方法，其中发生了所有魔法：

@Override
public boolean onDrag(View v, DragEvent event) {
    /*
    * You need to know the `Rect` (Rectangles) aka, the shape of your dragged `View` and your `View`, where you want to drop it.
    */

    Rect draggedImageRect = new Rect();
    Rect trashRect = new Rect();

    switch (event.getAction()) {
        case DragEvent.ACTION_DRAG_ENTERED:
            return true;
        case DragEvent.ACTION_DRAG_STARTED:
            return true;
        case DragEvent.ACTION_DRAG_LOCATION:
            return true;
        case DragEvent.ACTION_DRAG_EXITED:
            return true;
        case DragEvent.ACTION_DRAG_ENDED:
            return true;
        case DragEvent.ACTION_DROP:
            /*
            * The magic happens here. The user dragged your `View` to the `trashImage` and drops it:
             */

            float oldX = v.getX();
            float oldY = v.getY();
            v.setX(event.getX());
            v.setY(event.getY());
            v.getHitRect(draggedImageRect);
            trashImage.getHitRect(trashRect); //change trashImage with your variable

            /*
            * More magic happens here. We need to make sure, that only the drop to the trash will delete the dragged item.
            */
            if (Rect.intersects(draggedImageRect, trashRect)) {
                try {
                    int pos = Integer.parseInt(event.getClipData().getItemAt(0).getText().toString());

                    yourList.remove(pos);
                    yourAdapter.notifyItemRemoved(pos);
                } catch (Exception e) {
                    e.printStackTrace();
                }

            v.setX(oldX);
            v.setY(oldY);
            return true;
        default:
            return false;
    }
}

想要删除drop上的回收列表项以删除imageview。删除imageview在活动中定义

1 个答案: