java - Android - 使用 AnimatorSet 缩放动画

Question

官方Zooming a View教程使用 AnimatorSet放大 View。随着视野的扩大，它会产生向下运动的错觉。稍后，AnimatorSet 简单地向后重放以创建缩小的错觉。

我需要实现的是与此完全相反的情况。我需要从展开的 View 开始，然后向上移动将其缩小为较小的 View :

好像不能用例子里的反转码。该示例假定您首先放大 View 并将其展开，然后将其缩小回原始缩略图图标。

这是我到目前为止尝试过的方法。我的 XML 布局是

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent">

<LinearLayout android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#1999da">             

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:orientation="horizontal"
        android:layout_gravity="center"
        android:gravity="center">

        <!-- The final shrunk image -->

        <ImageView
            android:id="@+id/thumb_button_1"
            android:layout_width="wrap_content"
            android:layout_height="50dp"
            android:layout_marginRight="1dp"
            android:visibility="invisible"/>

    </LinearLayout>

</LinearLayout>

<!-- The initial expanded image that needs to be shrunk -->

<ImageView
    android:id="@+id/expanded_image"
    android:layout_width="wrap_content"
    android:layout_height="125dp"
    android:layout_gravity="center"
    android:src="@drawable/title_logo_expanded"
    android:scaleType="centerCrop"/>

</FrameLayout>

这里是执行缩小操作的方法。我基本上已经尝试颠倒教程中的过程:

private void zoomImageFromThumbReverse(final View expandedImageView, int imageResId, final int duration) {
    // If there's an animation in progress, cancel it immediately and proceed with this one.      

    if (mCurrentAnimator != null) {
        mCurrentAnimator.cancel();
    }

    // Load the low-resolution "zoomed-out" image.
    final ImageView thumbView = (ImageView) findViewById(R.id.thumb_button_1);
    thumbView.setImageResource(imageResId);

    // Calculate the starting and ending bounds for the zoomed-in image. This step
    // involves lots of math. Yay, math.
    final Rect startBounds = new Rect();
    final Rect finalBounds = new Rect();
    final Point globalOffset = new Point();

    // The start bounds are the global visible rectangle of the container view (i.e. the FrameLayout), and the
    // final bounds are the global visible rectangle of the thumbnail. Also
    // set the container view's offset as the origin for the bounds, since that's
    // the origin for the positioning animation properties (X, Y).
    findViewById(R.id.container).getGlobalVisibleRect(startBounds, globalOffset);
    thumbView.getGlobalVisibleRect(finalBounds);
    startBounds.offset(-globalOffset.x, -globalOffset.y);
    finalBounds.offset(-globalOffset.x, -globalOffset.y);

    // Adjust the start bounds to be the same aspect ratio as the final bounds using the
    // "center crop" technique. This prevents undesirable stretching during the animation.
    // Also calculate the start scaling factor (the end scaling factor is always 1.0).
    float startScale;
    if ((float) finalBounds.width() / finalBounds.height()
            > (float) startBounds.width() / startBounds.height()) {
        // Extend start bounds horizontally
        startScale = (float) startBounds.height() / finalBounds.height();
        float startWidth = startScale * finalBounds.width();
        float deltaWidth = (startWidth - startBounds.width()) / 2;
        startBounds.left -= deltaWidth;
        startBounds.right += deltaWidth;
    } else {
        // Extend start bounds vertically
        startScale = (float) startBounds.width() / finalBounds.width();
        float startHeight = startScale * finalBounds.height();
        float deltaHeight = (startHeight - startBounds.height()) / 2;
        startBounds.top -= deltaHeight;
        startBounds.bottom += deltaHeight;
    }

    // Hide the expanded-image and show the zoomed-out, thumbnail view. When the animation begins,
    // it will position the zoomed-in view in the place of the thumbnail.
    expandedImageView.setAlpha(0f);
    thumbView.setVisibility(View.VISIBLE);

    // Set the pivot point for SCALE_X and SCALE_Y transformations to the top-left corner of
    // the zoomed-in view (the default is the center of the view).
    thumbView.setPivotX(0f);
    thumbView.setPivotY(0f);

    // Construct and run the parallel animation of the four translation and scale properties
    // (X, Y, SCALE_X, and SCALE_Y).
    AnimatorSet set = new AnimatorSet();
    set
            .play(ObjectAnimator.ofFloat(thumbView, View.X, startBounds.left,
                    finalBounds.left))
            .with(ObjectAnimator.ofFloat(thumbView, View.Y, startBounds.top,
                    finalBounds.top))
            .with(ObjectAnimator.ofFloat(thumbView, View.SCALE_X, startScale, 1f))
            .with(ObjectAnimator.ofFloat(thumbView, View.SCALE_Y, startScale, 1f));
    //set.setDuration(mShortAnimationDuration);
    set.setDuration(duration);
    set.setInterpolator(new DecelerateInterpolator());
    set.addListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            mCurrentAnimator = null;
        }

        @Override
        public void onAnimationCancel(Animator animation) {
            mCurrentAnimator = null;
        }
    });
    set.start();
    mCurrentAnimator = set;

    // Upon clicking the zoomed-out image, it should zoom back down to the original bounds
    // and show the thumbnail instead of the expanded image.
    final float startScaleFinal = startScale;
    thumbView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (mCurrentAnimator != null) {
                mCurrentAnimator.cancel();
            }

            // Animate the four positioning/sizing properties in parallel, back to their
            // original values.
            AnimatorSet set = new AnimatorSet();
            set
                    .play(ObjectAnimator.ofFloat(thumbView, View.X, startBounds.left))
                    .with(ObjectAnimator.ofFloat(thumbView, View.Y, startBounds.top))
                    .with(ObjectAnimator
                            .ofFloat(thumbView, View.SCALE_X, startScaleFinal))
                    .with(ObjectAnimator
                            .ofFloat(thumbView, View.SCALE_Y, startScaleFinal));
            //set.setDuration(mShortAnimationDuration);
            set.setDuration(duration);
            set.setInterpolator(new DecelerateInterpolator());
            set.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    expandedImageView.setAlpha(1f);
                    thumbView.setVisibility(View.GONE);
                    mCurrentAnimator = null;
                }

                @Override
                public void onAnimationCancel(Animator animation) {
                    expandedImageView.setAlpha(1f);
                    thumbView.setVisibility(View.GONE);
                    mCurrentAnimator = null;
                }
            });
            set.start();
            mCurrentAnimator = set;
        }
    });
}

我在 onCreate() 中调用这个方法如下:

final View expandedImageView = findViewById(R.id.expanded_image);
new Handler().postDelayed(new Runnable(){
        public void run() {
            zoomImageFromThumbReverse(expandedImageView, R.drawable.title_logo_min, 1000);
        }}, 1000);

好吧，伙计们，就是这样。它不工作。我不知道为什么。演示示例完美运行，那么为什么它不起作用？看看我是不是疯了，然后告诉我。

谁能找出错误？或者指出我正确的方向？非常感谢所有帮助。

Answer 1

这是我最终使用的解决方案:

private void applyAnimation(final View startView, final View finishView, long duration) {
    float scalingFactor = ((float)finishView.getHeight())/((float)startView.getHeight());

    ScaleAnimation scaleAnimation =  new ScaleAnimation(1f, scalingFactor,
                                                        1f, scalingFactor,
                                                        Animation.RELATIVE_TO_SELF, 0.5f,
                                                        Animation.RELATIVE_TO_SELF, 0.5f);

    scaleAnimation.setDuration(duration);
    scaleAnimation.setInterpolator(new AccelerateDecelerateInterpolator());

    Display display = getWindowManager().getDefaultDisplay();

    int H;

    if(Build.VERSION.SDK_INT >= 13){
        Point size = new Point();
        display.getSize(size);
        H = size.y;
    }
    else{
        H = display.getHeight();
    }

    float h = ((float)finishView.getHeight());

    float verticalDisplacement = (-(H/2)+(3*h/4));

    TranslateAnimation translateAnimation = new TranslateAnimation(Animation.ABSOLUTE, 0,
                                                                   Animation.ABSOLUTE, 0,
                                                                   Animation.ABSOLUTE, 0,
                                                                   Animation.ABSOLUTE, verticalDisplacement);

    translateAnimation.setDuration(duration);
    translateAnimation.setInterpolator(new AccelerateDecelerateInterpolator());

    AnimationSet animationSet = new AnimationSet(false);
    animationSet.addAnimation(scaleAnimation);
    animationSet.addAnimation(translateAnimation);
    animationSet.setFillAfter(false);

    startView.startAnimation(animationSet);
}

这里的关键因素是TranslateAnimation参数中toYDelta的值:

toYDelta = (-(H/2)+(3*h/4));

理解为什么这有效是最主要的。剩下的大部分都很简单。