Android实现点击缩略图放大效果

import android.animation.Animator;import android.animation.AnimatorListenerAdapter;import android.animation.AnimatorSet;import android.animation.ObjectAnimator;import android.graphics.Point;import android.graphics.Rect;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.view.animation.DecelerateInterpolator;import android.widget.ImageView;public class MainActivity extends AppCompatActivity {  // 持有这个动画的引用，让他可以在动画执行中途取消  private Animator mCurrentAnimator;  private int mShortAnimationDuration;  private View imageView1;  private View imageView2;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    initView();    imageView1.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View v) {        zoomImageFromThumb(imageView1,R.mipmap.ic_launcher);      }    });    imageView2.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View v) {        zoomImageFromThumb(imageView2,R.mipmap.ic_launcher);      }    });    // 系统默认的短动画执行时间 200    mShortAnimationDuration = getResources().getInteger(        android.R.integer.config_shortAnimTime);  }  private void initView() {    imageView1 = (ImageView) findViewById(R.id.imageView1);    imageView2 = (ImageView) findViewById(R.id.imageView2);  }  private void zoomImageFromThumb(final View thumbView, int imageResId) {    // 如果有动画正在运行，取消这个动画    if (mCurrentAnimator != null) {      mCurrentAnimator.cancel();    }    // 加载显示大图的ImageView    final ImageView expandedImageView = (ImageView) findViewById(        R.id.expanded_image);    expandedImageView.setImageResource(imageResId);    // 计算初始小图的边界位置和最终大图的边界位置。    final Rect startBounds = new Rect();    final Rect finalBounds = new Rect();    final Point globalOffset = new Point();    // 小图的边界就是小ImageView的边界，大图的边界因为是铺满全屏的，所以就是整个布局的边界。    // 然后根据偏移量得到正确的坐标。    thumbView.getGlobalVisibleRect(startBounds);    findViewById(R.id.imageView1).getGlobalVisibleRect(finalBounds, globalOffset);    startBounds.offset(-globalOffset.x, -globalOffset.y);    finalBounds.offset(-globalOffset.x, -globalOffset.y);    // 计算初始的缩放比例。最终的缩放比例为1。并调整缩放方向，使看着协调。    float startScale=0;    if ((float) finalBounds.width() / finalBounds.height()        > (float) startBounds.width() / startBounds.height()) {      // 横向缩放      float startWidth = startScale * finalBounds.width();      float deltaWidth = (startWidth - startBounds.width()) / 2;      startBounds.left -= deltaWidth;      startBounds.right += deltaWidth;    } else {      // 竖向缩放      float startHeight = startScale * finalBounds.height();      float deltaHeight = (startHeight - startBounds.height()) / 2;      startBounds.top -= deltaHeight;      startBounds.bottom += deltaHeight;    }    // 隐藏小图，并显示大图    thumbView.setAlpha(0f);    expandedImageView.setVisibility(View.VISIBLE);    // 将大图的缩放中心点移到左上角。默认是从中心缩放    expandedImageView.setPivotX(0f);    expandedImageView.setPivotY(0f);    //对大图进行缩放动画    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;    // 点击大图时，反向缩放大图，然后隐藏大图，显示小图。    final float startScaleFinal = startScale;    expandedImageView.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View view) {        if (mCurrentAnimator != null) {          mCurrentAnimator.cancel();        }        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;      }    });  }}