我正在按照以下教程在Android http://developer.android.com/training/animation/zoom.html
中缩放图像除了我希望缩放的图像在视图中居中并且具有最大尺寸（不是教程中的fill_parent或match_parent）之外，一切都很有效。我有相同的代码，但我的XML不同，试图使图像居中，但它不起作用。有什么问题？
<FrameLayout.....
<RelativeLayout
android:id="@+id/te"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageView
android:id="@+id/memory_expanded_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:maxHeight="150dp"
android:maxWidth="150dp"
android:adjustViewBounds="true"
android:layout_centerInParent="true"
android:gravity="center"
android:scaleType="fitCenter"
android:visibility="invisible"
android:contentDescription="@string/description_zoom_touch_close" />
</RelativeLayout>
</FrameLayout>
部分缩放代码（与教程相同）。我想我需要在这里改变一些东西，finalBounds但我无法弄明白。
// 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 thumbnail,
// and the final bounds are the global visible rectangle of the container
// view. 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).
thumbView.getGlobalVisibleRect(startBounds);
findViewById(R.id.container)
.getGlobalVisibleRect(finalBounds, globalOffset);
startBounds.offset(-globalOffset.x, -globalOffset.y);
finalBounds.offset(-globalOffset.x, -globalOffset.y)
答案 0 :(得分：2)
您需要修改finalBounds以匹配图片的实际尺寸。像这样的东西
int imageHeight = expandedImageView.getHeight();
int imageWidth = expandedImageView.getWidth();
int horizontalMargin = 0, verticalMargin = 0;
if (imageHeight < finalBounds.height()) {
verticalMargin = (finalBounds.height() / 2) - (imageHeight / 2);
}
if (imageWidth < finalBounds.width()) {
horizontalMargin = (finalBounds.width() / 2) - (imageWidth / 2);
}
finalBounds.set(finalBounds.left + horizontalMargin, finalBounds.top + verticalMargin, finalBounds.right - horizontalMargin, finalBounds.bottom - verticalMargin);
完整代码：
布局：
<Framelayout
...
...
<ImageView
android:id="@+id/memory_expanded_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/description_zoom_touch_close"
android:visibility="invisible"/>
的活动：
private void zoomImageFromThumb(final View thumbView, int imageResId) {
// If there's an animation in progress, cancel it immediately and proceed with this one.
if (mCurrentAnimator != null) {
mCurrentAnimator.cancel();
}
// Load the high-resolution "zoomed-in" image.
final ImageView expandedImageView = (ImageView) findViewById(R.id.memory_expanded_image);
expandedImageView.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 thumbnail, and the
// final bounds are the global visible rectangle of the container view. 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).
thumbView.getGlobalVisibleRect(startBounds);
findViewById(R.id.container).getGlobalVisibleRect(finalBounds, globalOffset);
startBounds.offset(-globalOffset.x, -globalOffset.y);
finalBounds.offset(-globalOffset.x, -globalOffset.y);
//modify the final rect to match actual size of the image
int imageHeight = expandedImageView.getHeight();
int imageWidth = expandedImageView.getWidth();
int horizontalMargin = 0, verticalMargin = 0;
if (imageHeight < finalBounds.height()) {
verticalMargin = (finalBounds.height() / 2) - (imageHeight / 2);
}
if (imageWidth < finalBounds.width()) {
horizontalMargin = (finalBounds.width() / 2) - (imageWidth / 2);
}
finalBounds.set(finalBounds.left + horizontalMargin, finalBounds.top + verticalMargin, finalBounds.right - horizontalMargin, finalBounds.bottom - verticalMargin);
// 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 thumbnail and show the zoomed-in view. When the animation begins,
// it will position the zoomed-in view in the place of the thumbnail.
thumbView.setAlpha(0f);
expandedImageView.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).
expandedImageView.setPivotX(0f);
expandedImageView.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(expandedImageView, View.X, startBounds.left,
finalBounds.left))
.with(ObjectAnimator.ofFloat(expandedImageView, View.Y, startBounds.top,
finalBounds.top))
.with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_X, startScale, 1f))
.with(ObjectAnimator.ofFloat(expandedImageView, View.SCALE_Y, startScale, 1f));
set.setDuration(mShortAnimationDuration);
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-in image, it should zoom back down to the original bounds
// and show the thumbnail instead of the expanded image.
final float startScaleFinal = startScale;
expandedImageView.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(expandedImageView, View.X, startBounds.left))
.with(ObjectAnimator.ofFloat(expandedImageView, View.Y, startBounds.top))
.with(ObjectAnimator
.ofFloat(expandedImageView, View.SCALE_X, startScaleFinal))
.with(ObjectAnimator
.ofFloat(expandedImageView, View.SCALE_Y, startScaleFinal));
set.setDuration(mShortAnimationDuration);
set.setInterpolator(new DecelerateInterpolator());
set.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
@Override
public void onAnimationCancel(Animator animation) {
thumbView.setAlpha(1f);
expandedImageView.setVisibility(View.GONE);
mCurrentAnimator = null;
}
});
set.start();
mCurrentAnimator = set;
}
});
}