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() {
        @Override
        public 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;
        }

        @Override
        protected 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);
        }
    }
}

附件：https://files.cnblogs.com/shanzei/Gallery.zip

转自：http://flyingsir-zw.iteye.com/blog/1456523