使用ItemTouchHelper进行扫视以在扫出后显示另一个视图 [英] Use ItemTouchHelper for Swipe-To-Dismiss with another View displayed behind the swiped out

问题描述

我有一个RecyclerView，并且希望允许我的用户使用滑动手势从列表中删除项目.但是，从其他应用程序(例如Gmail)得知，我想在其后面显示一个删除图标，以便我的用户知道刷卡会导致删除.但是，我找不到一个明显的方法来做到这一点. ItemTouchHelper使用viewHolder.itemView，因此它占据了整行.

I have a RecyclerView and want to allow my users to use a swipe gesture to remove items from the list. But as known from other apps (e.g. Gmail), I want to show a delete icon behind it, so that my users know that swiping results in a remove. However, I can't find an obvious way to do that. The ItemTouchHelper uses the viewHolder.itemView, so it takes the whole row.

我的代码:

    ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new
            ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
                @Override
                public boolean onMove(
                        final RecyclerView recyclerView,
                        final RecyclerView.ViewHolder viewHolder,
                        final RecyclerView.ViewHolder target) {
                    return false;
                }

                @Override
                public void onSwiped(
                        final RecyclerView.ViewHolder viewHolder,
                        final int swipeDir) {
                    adapter.remove(viewHolder.getAdapterPosition());
                }
            };

    ItemTouchHelper itemTouchHelper = new ItemTouchHelper(
            simpleItemTouchCallback
    );
    itemTouchHelper.attachToRecyclerView(itemsRecyclerView);

    itemsRecyclerView.setLayoutManager(
            new LinearLayoutManager(getContext())
    );
    itemsRecyclerView.setAdapter(adapter);

如果有可能的话，有人能用胶水吗?我现在唯一能想到的就是扩展ItemTouchHelper/复制代码，而不是使用viewHolder.itemView，而是使用ID标识的视图.

Has anyone a glue if this is possible at all? The only thing I can imagine right now is to extend the ItemTouchHelper / copy the code, and instead of using viewHolder.itemView I take a view identified by an ID.

推荐答案

我通过对回收者视图项目使用以下布局结构来做到这一点:

I have done it with having the following layout structure for the recycler view item:

<FrameLayout
    background = dark>
    <AnyLayout with content
       android:id="@+id/removable">
    </AnyLayout>
<FrameLayout>

然后我将这个视图支架用作适配器中的基本视图支架:

Then I use this view holder as base view holder in my adapter:

public class RemovableViewHolder extends RecyclerView.ViewHolder {
    private View mRemoveableView;

    public RemovableViewHolder(final View itemView) {
        super(itemView);

        mRemoveableView = itemView.findViewById(R.id.removable);
    }

    public View getSwipableView() {
        return mRemoveableView;
    }
}

在我的ItemTouchHelper.Callback类中，我扩展了以下方法:

In my ItemTouchHelper.Callback class I extend the following methods like that:

@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    if (viewHolder instanceof RemovableViewHolder) {
        int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
        return makeMovementFlags(0, swipeFlags);
    } else
        return 0;
}

@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    getDefaultUIUtil().clearView(((RemovableViewHolder) viewHolder).getSwipableView());
}

@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
    if (viewHolder != null) {
        getDefaultUIUtil().onSelected(((RemovableViewHolder) viewHolder).getSwipableView());
    }
}

public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
    getDefaultUIUtil().onDraw(c, recyclerView, ((RemovableViewHolder) viewHolder).getSwipableView(), dX, dY,    actionState, isCurrentlyActive);
}

public void onChildDrawOver(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
    getDefaultUIUtil().onDrawOver(c, recyclerView, ((RemovableViewHolder) viewHolder).getSwipableView(), dX, dY,    actionState, isCurrentlyActive);
}

通过这种方法，您可以在布局中更多地使用一个级别，但是可以避免在Canvas上进行绘制的麻烦.另外，您还可以选择该项目内的其他视图，例如保存被触摸的视图并返回它，并使该项目的子项也可滑动.

With this approach you use one level in layouts more, but saves yourself troubles with drawing on Canvas. Also you may select other views inside the item, for example save one that was touched and return it and have children of an item also swipeable.

附加到回收者视图:

final ItemTouchHelper.Callback callback = new RemovableItemTouchHelperCallback(mAdapter);
final ItemTouchHelper touchHelper = new ItemTouchHelper(callback);
touchHelper.attachToRecyclerView(recyclerView)

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