使用ValueAnimator:

ValueAnimator expandAnimation = ValueAnimator.ofInt(mainView.getHeight(), 400);
expandAnimation.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
    @Override
    public void onAnimationUpdate(final ValueAnimator animation) {
        int height = (Integer) animation.getAnimatedValue();
        RelativeLayout.LayoutParams lp = (LayoutParams) mainView.getLayoutParams();
        lp.height = height;
    }
});


expandAnimation.setDuration(500);
expandAnimation.start();

这是我的解决方案，我的ImageView从100%增长到200%，并返回到原来的大小，使用res/anim/文件夹中的两个动画文件

anim_grow.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
 android:interpolator="@android:anim/accelerate_interpolator">
 <scale
  android:fromXScale="1.0"
  android:toXScale="2.0"
  android:fromYScale="1.0"
  android:toYScale="2.0"
  android:duration="3000"
  android:pivotX="50%"
  android:pivotY="50%"
  android:startOffset="2000" />
</set>

anim_shrink.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
 android:interpolator="@android:anim/accelerate_interpolator">
 <scale
  android:fromXScale="2.0"
  android:toXScale="1.0"
  android:fromYScale="2.0"
  android:toYScale="1.0"
  android:duration="3000"
  android:pivotX="50%"
  android:pivotY="50%"
  android:startOffset="2000" />
</set>

发送一个ImageView到setAnimationGrowShrink()方法

ImageView img1 = (ImageView)findViewById(R.id.image1);
setAnimationGrowShrink(img1);

setAnimationGrowShrink()方法:

private void setAnimationGrowShrink(final ImageView imgV){
    final Animation animationEnlarge = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.anim_grow);
    final Animation animationShrink = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.anim_shrink);

    imgV.startAnimation(animationEnlarge);

    animationEnlarge.setAnimationListener(new AnimationListener() {         
        @Override
        public void onAnimationStart(Animation animation) {}

        @Override
        public void onAnimationRepeat(Animation animation) {}

        @Override
        public void onAnimationEnd(Animation animation) {
            imgV.startAnimation(animationShrink);
        }
    });

    animationShrink.setAnimationListener(new AnimationListener() {          
        @Override
        public void onAnimationStart(Animation animation) {}

        @Override
        public void onAnimationRepeat(Animation animation) {}

        @Override
        public void onAnimationEnd(Animation animation) {
            imgV.startAnimation(animationEnlarge);
        }
    });

}

是的，我同意上面的评论。事实上，它似乎是正确的(或者至少是最简单的?)事情要做的是指定(在XML中)一个初始布局高度“0px”——然后你可以传递另一个参数“toHeight”(即“最终高度”)到你的自定义动画子类的构造函数，例如，在上面的例子中，它看起来像这样:

    public DropDownAnim( View v, int toHeight ) { ... }

不管怎样，希望这能有所帮助!：）

根据@Tom Esterez和@Seth Nelson的解决方案，我对它们进行了简化。与原始解决方案一样，它不依赖于开发人员选项(动画设置)。

private void resizeWithAnimation(final View view, int duration, final int targetHeight) {
    final int initialHeight = view.getMeasuredHeight();
    final int distance = targetHeight - initialHeight;

    view.setVisibility(View.VISIBLE);

    Animation a = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            if (interpolatedTime == 1 && targetHeight == 0) {
                view.setVisibility(View.GONE);
            }
            view.getLayoutParams().height = (int) (initialHeight + distance * interpolatedTime);
            view.requestLayout();
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };

    a.setDuration(duration);
    view.startAnimation(a);
}

我试图做一个我认为非常相似的动画，并找到了一个优雅的解决方案。这段代码假设你总是从0->h或h->0 (h是最大高度)。三个构造函数参数是view =要动画的视图(在我的例子中是webview)， targetHeight =视图的最大高度，以及down =一个布尔值，用于指定方向(true =展开，false =折叠)。

public class DropDownAnim extends Animation {
    private final int targetHeight;
    private final View view;
    private final boolean down;

    public DropDownAnim(View view, int targetHeight, boolean down) {
        this.view = view;
        this.targetHeight = targetHeight;
        this.down = down;
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        int newHeight;
        if (down) {
            newHeight = (int) (targetHeight * interpolatedTime);
        } else {
            newHeight = (int) (targetHeight * (1 - interpolatedTime));
        }
        view.getLayoutParams().height = newHeight;
        view.requestLayout();
    }

    @Override
    public void initialize(int width, int height, int parentWidth,
            int parentHeight) {
        super.initialize(width, height, parentWidth, parentHeight);
    }

    @Override
    public boolean willChangeBounds() {
        return true;
    }
}

这是我的解决方案。我认为这样更简单。它只是扩展了视图，但很容易扩展。

public class WidthExpandAnimation extends Animation
{
    int _targetWidth;
    View _view;

    public WidthExpandAnimation(View view)
    {
        _view = view;
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t)
    {
        if (interpolatedTime < 1.f)
        {
            int newWidth = (int) (_targetWidth * interpolatedTime);

            _view.layout(_view.getLeft(), _view.getTop(),
                    _view.getLeft() + newWidth, _view.getBottom());
        }
        else
            _view.requestLayout();
    }

    @Override
    public void initialize(int width, int height, int parentWidth, int parentHeight)
    {
        super.initialize(width, height, parentWidth, parentHeight);

        _targetWidth = width;
    }

    @Override
    public boolean willChangeBounds() {
        return true;
    }
}