Android - 在 LinearLayout 或 RelativeLayout 中为 View 的 topMargin/bottomMargin/等设置动画

Question

我正在尝试创建一个从底部向上滑动的菜单。它从屏幕底部可见的菜单 View 开始，然后单击它会使它向上滑动。我尝试使用 TranslateAnimation，但尽管像素移动了，但菜单的点击区域仍处于与以前相同的位置。所以我认为如果我可以在动画完成后调整菜单的边距，这将实现我想要的。但是，我不知道如何调整边距。

我已经尝试创建一个 LinearLayout.LayoutMargins 对象，然后设置其边距并将其应用于菜单 View (这是一个 LinearLayout)，但这并没有'工作。

有什么想法吗？

Answer 1

以下对我有用。首先确定向上(完全可见)或向下(大部分隐藏)菜单的底部边距(倾斜)。

private static final int BOTTOM_MARGIN_UP = -50; // My menu view is a bit too tall.
private static final int BOTTOM_MARGIN_DOWN = -120;

然后，在 onCreate() 中:

menuLinearLayout = (LinearLayout)findViewById(R.id.menuLinearLayout);
setBottomMargin(menuLinearLayout, BOTTOM_MARGIN_DOWN);

upAnimation = makeAnimation(BOTTOM_MARGIN_DOWN, BOTTOM_MARGIN_UP);
downAnimation = makeAnimation(BOTTOM_MARGIN_UP, BOTTOM_MARGIN_DOWN);

Button toggleMenuButton = (Button)findViewById(R.id.toggleMenuButton);
toggleMenuButton.setOnTouchListener(new View.OnTouchListener()
{
    public boolean onTouch(View view, MotionEvent motionEvent)
    {
        if (motionEvent.getAction() != MotionEvent.ACTION_DOWN) return false;
        ViewGroup.MarginLayoutParams layoutParams =
            (ViewGroup.MarginLayoutParams)menuLinearLayout.getLayoutParams();
        boolean isUp = layoutParams.bottomMargin == dipsToPixels(BOTTOM_MARGIN_UP);
        menuLinearLayout.startAnimation(isUp ? downAnimation : upAnimation);
        return true;
    }
});

秘诀来了;-)

private TranslateAnimation makeAnimation(final int fromMargin, final int toMargin)
{
    TranslateAnimation animation = 
        new TranslateAnimation(0, 0, 0, dipsToPixels(fromMargin - toMargin));
    animation.setDuration(250);
    animation.setAnimationListener(new Animation.AnimationListener()
    {
        public void onAnimationEnd(Animation animation)
        {
            // Cancel the animation to stop the menu from popping back.
            menuLinearLayout.clearAnimation();

            // Set the new bottom margin.
            setBottomMargin(menuLinearLayout, toMargin);
        }

        public void onAnimationStart(Animation animation) {}

        public void onAnimationRepeat(Animation animation) {}
    });
    return animation;
}

我使用了两个效用函数:

private void setBottomMargin(View view, int bottomMarginInDips)
{
    ViewGroup.MarginLayoutParams layoutParams =    
        (ViewGroup.MarginLayoutParams)view.getLayoutParams();
    layoutParams.bottomMargin = dipsToPixels(bottomMarginInDips);
    view.requestLayout();
}

private int dipsToPixels(int dips)
{
    final float scale = getResources().getDisplayMetrics().density;
    return (int)(dips * scale + 0.5f);
}

瞧!