如何为左右滑动分别添加两个不同的背景

Question

我正在使用ItemTouchHelp允许向左和向右滑动以执行不同的操作，即向左滑动以进行删除和向右滑动以进行编辑。但是，我无法使背景正常工作。

我没有编码onDraw方法，而是在主布局下使用了两种不同的布局，并且在滑动时根据方向仅对其中的两个进行动画处理。或者至少那是我打算做的。这类似于Gmail或Outlook应用程序。

但是，当我开始滑动然后放开时，顶层不返回。取而代之的是，它被我随其移动的图层所代替。例如。如果我想向左滑动即可删除，并且还要移动编辑层以显示删除层。所以，如果我放手，那么我会看到编辑层。

以下是recyclerview中一种视图类型的布局文件（我有两个，但是它们都使用相同的UX）：

<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.card.MaterialCardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="4dp"
    android:orientation="vertical">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@color/colorPrimaryDark"
            android:id="@+id/midground_view">

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="match_parent"
                    android:layout_alignParentStart="true"
                    android:layout_centerVertical="true"
                    android:layout_margin="2dp"
                    android:id="@+id/edit_icon"
                    android:src="@drawable/icon_edit"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_centerVertical="true"
                    android:layout_toEndOf="@+id/edit_icon"
                    android:text="EDIT"
                    android:layout_margin="2dp"
                    android:textStyle="bold"
                    android:textColor="#FFFFFF"/>

        </RelativeLayout>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@color/colorAccent"
            android:id="@+id/background_view">

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="match_parent"
                    android:layout_alignParentEnd="true"
                    android:layout_centerVertical="true"
                    android:layout_margin="2dp"
                    android:id="@+id/delete_icon"
                    android:src="@drawable/icon_delete"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_centerVertical="true"
                    android:layout_toStartOf="@+id/delete_icon"
                    android:layout_margin="2dp"
                    android:text="DELETE"
                    android:textStyle="bold"
                    android:textColor="#FFFFFF"/>

        </RelativeLayout>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@color/colorBackground"
            android:id="@+id/foreground_view">

                <ImageView
                    android:id="@+id/menu_item_image"
                    android:layout_width="match_parent"
                    android:layout_height="160dp"
                    android:adjustViewBounds="true"
                    android:scaleType="fitXY" />

                <com.google.android.material.textview.MaterialTextView
                    android:id="@+id/menu_item_name"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_below="@id/menu_item_image"
                    android:layout_alignParentStart="true"
                    android:layout_marginStart="4dp"
                    android:layout_marginTop="4dp"
                    android:layout_marginEnd="4dp"
                    android:text="Item Name"
                    android:textStyle="bold" />

                <com.google.android.material.textview.MaterialTextView
                    android:id="@+id/menu_item_price_pickup"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_below="@id/menu_item_description"
                    android:layout_alignParentStart="true"
                    android:layout_marginStart="4dp"
                    android:layout_marginTop="4dp"
                    android:text="Pickup price"
                    android:textStyle="bold" />

                <com.google.android.material.textview.MaterialTextView
                    android:id="@+id/menu_item_price_delivery"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_below="@id/menu_item_description"
                    android:layout_toEndOf="@id/menu_item_price_pickup"
                    android:layout_marginStart="32dp"
                    android:layout_marginTop="4dp"
                    android:text="Delivery price"
                    android:textStyle="bold" />

                <com.google.android.material.textview.MaterialTextView
                    android:id="@+id/menu_item_description"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_below="@id/menu_item_name"
                    android:layout_alignParentStart="true"
                    android:layout_marginStart="4dp"
                    android:layout_marginBottom="4dp"
                    android:layout_marginTop="4dp"
                    android:layout_marginEnd="4dp"
                    android:ellipsize="end"
                    android:marqueeRepeatLimit="marquee_forever"
                    android:maxLines="2"
                    android:text="Lengthy menu description goes here" />

        </RelativeLayout>

</com.google.android.material.card.MaterialCardView>

这是我的ItemTouchHelper类，其中前景是包含带有数据的子项的布局，背景是删除图标（向左滑动时显示），而中间具有编辑图标（向右滑动时显示）：< / p>

public class RecyclerItemTouchHelper extends ItemTouchHelper.SimpleCallback {

    private RecyclerItemTouchHelperListener listener;

    public RecyclerItemTouchHelper(int dragDirs, int swipeDirs, RecyclerItemTouchHelperListener listener) {
        super(dragDirs, swipeDirs);
        this.listener = listener;
    }

    @Override
    public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
        return true;
    }

    @Override
    public void onSelectedChanged(@Nullable RecyclerView.ViewHolder viewHolder, int actionState) {
        if (viewHolder != null) {
            int viewType = viewHolder.getItemViewType();
            if (viewType == R.layout.item_menu_dish) {
                final View foregroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewForeground;
                getDefaultUIUtil().onSelected(foregroundView);
            } else if (viewType == R.layout.item_menu_section) {
                final View foregroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewForeground;
                getDefaultUIUtil().onSelected(foregroundView);
            }
        }
    }

    @Override
    public void onChildDrawOver(@NonNull Canvas c, @NonNull RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
        if (viewHolder != null) {
            if (dX < 0) {
                int viewType = viewHolder.getItemViewType();
                if (viewType == R.layout.item_menu_dish) {
                    final View foregroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewForeground;
                    final View backgroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewBackground;
                    getDefaultUIUtil().onDrawOver(c, recyclerView, backgroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDrawOver(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                } else if (viewType == R.layout.item_menu_section) {
                    final View foregroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewForeground;
                    final View backgroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewBackground;
                    getDefaultUIUtil().onDraw(c, recyclerView, backgroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDrawOver(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                }
            } else if (dX > 0) {
                int viewType = viewHolder.getItemViewType();
                if (viewType == R.layout.item_menu_dish) {
                    final View foregroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewForeground;
                    final View midgroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewMidGround;
                    getDefaultUIUtil().onDrawOver(c, recyclerView, midgroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDrawOver(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                } else if (viewType == R.layout.item_menu_section) {
                    final View midgroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewMidGround;
                    final View foregroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewForeground;
                    getDefaultUIUtil().onDrawOver(c, recyclerView, midgroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDrawOver(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                }
            }
        }
    }

    @Override
    public void clearView(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) {
        int viewType = viewHolder.getItemViewType();
        if (viewType == R.layout.item_menu_dish) {
            final View foregroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewForeground;
            getDefaultUIUtil().clearView(foregroundView);
        } else if (viewType == R.layout.item_menu_section) {
            final View foregroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewForeground;
            getDefaultUIUtil().clearView(foregroundView);
        }
    }

    @Override
    public void onChildDraw(@NonNull Canvas c, @NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
        if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
            if (dX < 0) {
                int viewType = viewHolder.getItemViewType();
                if (viewType == R.layout.item_menu_dish) {
                    final View foregroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewForeground;
                    final View backgroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewBackground;
                    getDefaultUIUtil().onDraw(c, recyclerView, backgroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDraw(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                } else if (viewType == R.layout.item_menu_section) {
                    final View foregroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewForeground;
                    final View backgroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewBackground;
                    getDefaultUIUtil().onDraw(c, recyclerView, backgroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDraw(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                }
            } else if (dX > 0) {
                int viewType = viewHolder.getItemViewType();
                if (viewType == R.layout.item_menu_dish) {
                    final View foregroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewForeground;
                    final View midgroundView = ((MenuAdapter.DishViewHolder) viewHolder).viewMidGround;
                    getDefaultUIUtil().onDraw(c, recyclerView, midgroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDraw(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                } else if (viewType == R.layout.item_menu_section) {
                    final View foregroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewForeground;
                    final View midgroundView = ((MenuAdapter.SectionViewHolder) viewHolder).viewMidGround;
                    getDefaultUIUtil().onDraw(c, recyclerView, foregroundView, dX, dY, actionState, isCurrentlyActive);
                    getDefaultUIUtil().onDraw(c, recyclerView, midgroundView, dX, dY, actionState, isCurrentlyActive);
                }
            }
        } else {
            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
        }
    }

    @Override
    public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction) {
        listener.onSwiped(viewHolder, direction, viewHolder.getAdapterPosition());
    }

    @Override
    public int convertToAbsoluteDirection(int flags, int layoutDirection) {
        return super.convertToAbsoluteDirection(flags, layoutDirection);
    }

    public interface RecyclerItemTouchHelperListener {
        void onSwiped (RecyclerView.ViewHolder viewHolder, int direction, int position);
    }
}