关于callback中onChildDraw方法参数的建议

[kidloserme]

建议把Callback类中的onChildDraw方法的第三个参数由ViewHolder类型改为Extension类型，并为Extension新增两个接口，getItemView和getTranslateView。这样就可以为使用者提供一个默认的callback，省去使用者再自己定义callback并在onChildDraw进行类型判断的步骤。下面是我使用的示例：

public interface Extension {
    float getActionWidth();
    View getTranslateView();
    View getItemView();
}

自定义的callback中onChildDraw

@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, Extension extension, float dX, float dY, int actionState, boolean isCurrentlyActive) {
    extension.getTranslateView().setTranslationX(dX);
}

ItemTouchHelperExtension中调用onChildDraw的修改

private void onDraw(Canvas c, RecyclerView parent, ViewHolder selected,
                    List<RecoverAnimation> recoverAnimationList,
                    int actionState, float dX, float dY) {
    final int recoverAnimSize = recoverAnimationList.size();
    for (int i = 0; i < recoverAnimSize; i++) {
        final RecoverAnimation anim = recoverAnimationList.get(i);
        anim.update();
        final int count = c.save();
        onChildDraw(c, parent, (Extension) anim.mViewHolder, anim.mX, anim.mY, anim.mActionState,
                false);
        c.restoreToCount(count);
    }
    if (selected != null) {
        final int count = c.save();
        onChildDraw(c, parent, (Extension) selected, dX, dY, actionState, true);
        c.restoreToCount(count);
    }
}