自定义Gallery 滑动中图片自动突出显示

package org.pskink;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Matrix;import android.os.Handler;import android.os.Message;import android.util.AttributeSet;import android.util.Log;import android.view.View;import android.view.animation.Animation;import android.view.animation.Transformation;import android.widget.AdapterView;import android.widget.Gallery;import android.widget.ImageView;import android.widget.AdapterView.OnItemSelectedListener;public class AnimatedSizingGallery extends Gallery implements OnItemSelectedListener {public static final String TAG = "AnimatedSizingGallery";private static final int MSG_ZOOM_IN = 1;private  static final long DELAY = 100;private View mPrev;private float mAnimationScale;private float mAnimationOffsetY;private int mAnimationDuration;public AnimatedSizingGallery(Context context, AttributeSet attrs) {super(context, attrs);TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.AnimatedSizingGallery);mAnimationScale = a.getFloat(R.styleable.AnimatedSizingGallery_animationScale, 2);mAnimationOffsetY = a.getFloat(R.styleable.AnimatedSizingGallery_animationOffsetY, 0);mAnimationDuration = a.getInteger(R.styleable.AnimatedSizingGallery_animationDuration, 500);a.recycle();setOnItemSelectedListener(this);}public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {if (mPrev != null) {zoomOut();}mPrev = view;mGalleryHandler.removeCallbacksAndMessages(view);Message msg = Message.obtain(mGalleryHandler, MSG_ZOOM_IN, view);mGalleryHandler.sendMessageDelayed(msg, DELAY);}public void onNothingSelected(AdapterView<?> parent) {Log.d(TAG, "onNothingSelected called !!!");if (mPrev != null) {zoomOut();mPrev = null;}}private void zoomOut() {if (mGalleryHandler.hasMessages(MSG_ZOOM_IN, mPrev)) {mGalleryHandler.removeCallbacksAndMessages(mPrev);} else {ZoomAnimation a = (ZoomAnimation) mPrev.getAnimation();a.resetForZoomOut();mPrev.startAnimation(a);}}Handler mGalleryHandler = new Handler() {@Overridepublic void dispatchMessage(Message msg) {if (msg.what == MSG_ZOOM_IN) {ImageView view = (ImageView) msg.obj;Animation a = new ZoomAnimation(view, 1, mAnimationScale, mAnimationOffsetY, mAnimationDuration);view.startAnimation(a);}}};class ZoomAnimation extends Animation {private float mFrom;private float mTo;private float mOffsetY;private int mPivotX;private int mPivotY;private float mInterpolatedTime;public ZoomAnimation(View v, float from, float to, float offsetY, int duration) {super();mFrom = from;mTo = to;mOffsetY = offsetY * v.getHeight();setDuration(duration);setFillAfter(true);mPivotX = v.getWidth() / 2;mPivotY = v.getHeight() / 2;}public void resetForZoomOut() {reset();mOffsetY = 0;mFrom = mFrom + (mTo - mFrom) * mInterpolatedTime;mTo = 1;}@Overrideprotected void applyTransformation(float interpolatedTime, Transformation t) {mInterpolatedTime = interpolatedTime;        float s = mFrom + (mTo - mFrom) * interpolatedTime;        Matrix matrix = t.getMatrix();        if (mOffsetY != 0) {        matrix.preTranslate(0, mOffsetY * interpolatedTime);        }        if (mTo == 1) {        matrix.preRotate(360 * interpolatedTime, mPivotX, mPivotY);        }            matrix.preScale(s, s, mPivotX, mPivotY);}}}