图片的放大缩小

点击图片，放大，再点击图片缩小。

import android.animation.Animator;import android.animation.AnimatorListenerAdapter;import android.animation.AnimatorSet;import android.animation.ObjectAnimator;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Point;import android.graphics.Rect;import android.view.View;import android.view.animation.DecelerateInterpolator;import android.widget.ImageView;public class ZoomUtil {private Animator mCurrentAnimator;private int mShortAnimationDuration;private Activity mActivity ; public ZoomUtil(Activity activity){mActivity = activity ;mShortAnimationDuration = activity.getResources().getInteger(android.R.integer.config_shortAnimTime);}public 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) mActivity.findViewById(R.id.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);       mActivity.findViewById(R.id.container).getGlobalVisibleRect(finalBounds, globalOffset);       startBounds.offset(-globalOffset.x, -globalOffset.y);       finalBounds.offset(-globalOffset.x, -globalOffset.y);       finalBounds.top = -(globalOffset.y*3) ;       // 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, 1.5f));       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;           }       });   }public void zoomImageFromThumb(final View thumbView, Bitmap bitmap) {// 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) mActivity.findViewById(R.id.expanded_image);expandedImageView.setImageBitmap(bitmap); // 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);mActivity.findViewById(R.id.container).getGlobalVisibleRect(finalBounds, globalOffset);startBounds.offset(-globalOffset.x, -globalOffset.y);finalBounds.offset(-globalOffset.x, globalOffset.y);finalBounds.top = -(globalOffset.y*3) ; // 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 horizontallystartScale = (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 verticallystartScale = (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, 1.5f));set.setDuration(mShortAnimationDuration);set.setInterpolator(new DecelerateInterpolator());set.addListener(new AnimatorListenerAdapter() {@Overridepublic void onAnimationEnd(Animator animation) {mCurrentAnimator = null;} @Overridepublic 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() {@Overridepublic 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() {@Overridepublic void onAnimationEnd(Animator animation) {thumbView.setAlpha(1f);expandedImageView.setVisibility(View.GONE);mCurrentAnimator = null;} @Overridepublic void onAnimationCancel(Animator animation) {thumbView.setAlpha(1f);expandedImageView.setVisibility(View.GONE);mCurrentAnimator = null;}});set.start();mCurrentAnimator = set;}});}}

R.id.container 是最顶层的layout 容器。

<ImageView        android:id="@+id/expanded_image"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:visibility="gone"        android:contentDescription="@string/image_contentDescription" />