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; } }); } }