如何在 Android 中为 LayoutParams x 和 y 设置动画

How to animate LayoutParams x and y in Android

我是 android 的新手。 我有以下代码:

// layoutParams of type WindowManager.LayoutParams
layoutParams.x = someX;
layoutParams.y = someY;
windowManager.updateViewLayout(someView, layoutParams);

如何使这种变化动起来?翻译之类的东西...

您可以使用 ValueAnimator:

int beginValue = 0;
int endValue = 100;

ValueAnimator animator = ValueAnimator.ofInt(beginValue, endValue);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
    @Override
    public void onAnimationUpdate(ValueAnimator animation) {
        WindowManager.LayoutParams layoutParams =
                (WindowManager.LayoutParams) view.getLayoutParams();
        layoutParams.x = (Integer) animation.getAnimatedValue();
        layoutParams.y = (Integer) animation.getAnimatedValue();
        getWindowManager().updateViewLayout(view, params);
    }
});
animator.start();

在 x 和 y 上设置动画时,最好使用 属性 Value Holders。

public void animate(final View v, int startX, int endX, int startY, int endY) {

    PropertyValuesHolder pvhX = PropertyValuesHolder.ofInt("x", startX, endX);
    PropertyValuesHolder pvhY = PropertyValuesHolder.ofInt("y", startY, endY);

    ValueAnimator translator = ValueAnimator.ofPropertyValuesHolder(pvhX, pvhY);

    translator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {
            WindowManager.LayoutParams layoutParams = (WindowManager.LayoutParams) v.getLayoutParams();
            layoutParams.x = (Integer) valueAnimator.getAnimatedValue("x");
            layoutParams.y = (Integer) valueAnimator.getAnimatedValue("y");
            windowManager.updateViewLayout(v, layoutParams);
        }
    });

    translator.setDuration(100);
    translator.start();
}

我发现的类似问题的最简单解决方案如下所示:https://www.youtube.com/watch?v=55wLsaWpQ4g

在我的例子中,我有一个 RelativeLayout 并且想以编程方式更改它的 android:layout_below 值(它的父级也是 RelativeLayout)。

所以在 onCreate 我输入了:

LayoutTransition layoutTransition = rlListLayout.getLayoutTransition();
layoutTransition.enableTransitionType(LayoutTransition.CHANGING);

然后例如在 onClick 方法中更改了布局参数:

RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) rl.getLayoutParams();
params.addRule(RelativeLayout.BELOW, R.id.dummy);
rl.setLayoutParams(params);

就是这样。 5行代码,无需计算位置,也无需测量任何东西。