如果你不想扩展或折叠所有的方式-这里是一个简单的HeightAnimation -

import android.view.View;
import android.view.animation.Animation;
import android.view.animation.Transformation;

public class HeightAnimation extends Animation {
    protected final int originalHeight;
    protected final View view;
    protected float perValue;

    public HeightAnimation(View view, int fromHeight, int toHeight) {
        this.view = view;
        this.originalHeight = fromHeight;
        this.perValue = (toHeight - fromHeight);
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        view.getLayoutParams().height = (int) (originalHeight + perValue * interpolatedTime);
        view.requestLayout();
    }

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

用法:

HeightAnimation heightAnim = new HeightAnimation(view, view.getHeight(), viewPager.getHeight() - otherView.getHeight());
heightAnim.setDuration(1000);
view.startAnimation(heightAnim);

好吧，我刚刚发现了一个非常丑陋的解决方案:

public static Animation expand(final View v, Runnable onEnd) {
    try {
        Method m = v.getClass().getDeclaredMethod("onMeasure", int.class, int.class);
        m.setAccessible(true);
        m.invoke(
            v,
            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
            MeasureSpec.makeMeasureSpec(((View)v.getParent()).getMeasuredHeight(), MeasureSpec.AT_MOST)
        );
    } catch (Exception e){
        Log.e("test", "", e);
    }
    final int initialHeight = v.getMeasuredHeight();
    Log.d("test", "initialHeight="+initialHeight);

    v.getLayoutParams().height = 0;
    v.setVisibility(View.VISIBLE);
    Animation a = new Animation()
    {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            final int newHeight = (int)(initialHeight * interpolatedTime);
            v.getLayoutParams().height = newHeight;
            v.requestLayout();
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };
    a.setDuration(5000);
    v.startAnimation(a);
    return a;
}

请随意提出一个更好的解决方案!

我看到这个问题很受欢迎，所以我发布了我的实际解决方案。主要的优点是你不需要知道扩展的高度来应用动画，一旦视图被扩展，它会在内容改变时适应高度。这对我来说很有效。

public static void expand(final View v) {
    int matchParentMeasureSpec = View.MeasureSpec.makeMeasureSpec(((View) v.getParent()).getWidth(), View.MeasureSpec.EXACTLY);
    int wrapContentMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    v.measure(matchParentMeasureSpec, wrapContentMeasureSpec);
    final int targetHeight = v.getMeasuredHeight();
    
    // Older versions of android (pre API 21) cancel animations for views with a height of 0.
    v.getLayoutParams().height = 1;
    v.setVisibility(View.VISIBLE);
    Animation a = new Animation()
    {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            v.getLayoutParams().height = interpolatedTime == 1
                    ? LayoutParams.WRAP_CONTENT
                    : (int)(targetHeight * interpolatedTime);
            v.requestLayout();
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };
    
    // Expansion speed of 1dp/ms
    a.setDuration((int)(targetHeight / v.getContext().getResources().getDisplayMetrics().density));
    v.startAnimation(a);
}

public static void collapse(final View v) {
    final int initialHeight = v.getMeasuredHeight();

    Animation a = new Animation()
    {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            if(interpolatedTime == 1){
                v.setVisibility(View.GONE);
            }else{
                v.getLayoutParams().height = initialHeight - (int)(initialHeight * interpolatedTime);
                v.requestLayout();
            }
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };
    
    // Collapse speed of 1dp/ms
    a.setDuration((int)(initialHeight / v.getContext().getResources().getDisplayMetrics().density));
    v.startAnimation(a);
}

正如@Jefferson在评论中提到的，你可以通过改变动画的持续时间(以及速度)来获得更流畅的动画。目前，它已设置为1dp/ms的速度

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);
        }
    });

}

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;
    }
}

@Tom Esterez的回答，但更新为正确使用view.measure()每个Android getMeasuredHeight返回错误的值!

    // http://easings.net/
    Interpolator easeInOutQuart = PathInterpolatorCompat.create(0.77f, 0f, 0.175f, 1f);

    public static Animation expand(final View view) {
        int matchParentMeasureSpec = View.MeasureSpec.makeMeasureSpec(((View) view.getParent()).getWidth(), View.MeasureSpec.EXACTLY);
        int wrapContentMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
        view.measure(matchParentMeasureSpec, wrapContentMeasureSpec);
        final int targetHeight = view.getMeasuredHeight();

        // Older versions of android (pre API 21) cancel animations for views with a height of 0 so use 1 instead.
        view.getLayoutParams().height = 1;
        view.setVisibility(View.VISIBLE);

        Animation animation = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {

               view.getLayoutParams().height = interpolatedTime == 1
                    ? ViewGroup.LayoutParams.WRAP_CONTENT
                    : (int) (targetHeight * interpolatedTime);

            view.requestLayout();
        }

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

        animation.setInterpolator(easeInOutQuart);
        animation.setDuration(computeDurationFromHeight(view));
        view.startAnimation(animation);

        return animation;
    }

    public static Animation collapse(final View view) {
        final int initialHeight = view.getMeasuredHeight();

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

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

        a.setInterpolator(easeInOutQuart);

        int durationMillis = computeDurationFromHeight(view);
        a.setDuration(durationMillis);

        view.startAnimation(a);

        return a;
    }

    private static int computeDurationFromHeight(View view) {
        // 1dp/ms * multiplier
        return (int) (view.getMeasuredHeight() / view.getContext().getResources().getDisplayMetrics().density);
    }