BottomSheet自定义行为- BottomBar之上

Question

我想在我的BottomSheet上面显示BottomBar。因此，我必须编写自定义的BottomSheet behavior，将我的BottomSheet放在BottomBar之上-- BottomBar有shy behavior (滚动时隐藏)。

以下是我试图实现的：

public class BottomSheetBehavior<T extends View> extends android.support.design.widget.BottomSheetBehavior<T> {

public BottomSheetBehavior(Context context, AttributeSet attrs) {
    super(context, attrs);
}

@Override
public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
    return dependency instanceof BottomBar;
}

@Override
public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
    // This will set the Y of my bottom sheet above the bottom bar every time BottomBar changes its position
    child.setY(dependency.getY() - child.getHeight());
    // But I also have to modify the bottom position of my BottomSheet 
    // so the BottomSheet knows when its collapsed in its final bottom position.
    child.setBottom((int) dependency.getY() - dependency.getHeight());
    return false;
}

}

到目前为止，这一解决办法尚未完全奏效。我可以将BottomSheet放在BottomBar之上，并使用setY()方法。但是膨胀和崩溃是错误的。因此，我尝试用方法BottomSheet修改setBottom()底部，但两者都不能工作。也许是因为错误的单位(px对dp)。

有人能帮我修复我的代码吗?或者至少给我一些提示，我到底做错了什么，或者我错过了什么？

Answer 1

所以我拿出了自己的解决方案。虽然有一些问题必须解决--比如BottomBar上方的阴影或BottomSheet被删除时隐藏的BottomBar --但它仍然工作得很好。

对于那些面临同样或类似问题的人，我有解决办法。

public class MyBottomSheetBehavior<T extends View> extends android.support.design.widget.BottomSheetBehavior<T> {

    private boolean mDependsOnBottomBar = true;

    public MyBottomSheetBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, T child, View dependency) {
        return (dependency instanceof BottomBar) || super.layoutDependsOn(parent, child, dependency);
    }

    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, T child, View dependency) {
        if (dependency instanceof BottomBar) {

            BottomBar bottomBar = (BottomBar) dependency;

            if (mDependsOnBottomBar) {
                //TODO this 4dp margin is actual shadow layout height, which is 4 dp in bottomBar library ver. 2.0.2
                float transitionY = bottomBar.getTranslationY() - bottomBar.getHeight()
                    + (getState() != STATE_EXPANDED ? Utils.dpToPixel(ContextProvider.getContext(), 4L) : 0F);
                child.setTranslationY(Math.min(transitionY, 0F));
            }

            if (bottomBar.getTranslationY() >= bottomBar.getHeight()) {
                mDependsOnBottomBar = false;
                bottomBar.setVisibility(View.GONE);
            }
            if (getState() != STATE_EXPANDED) {
                mDependsOnBottomBar = true;
                bottomBar.setVisibility(View.VISIBLE);
            }

            return false;
        }
        return super.onDependentViewChanged(parent, child, dependency);
    }
}