GalleryFlow.java

package com.xiawenquan;

import android.content.Context;
import android.graphics.Camera;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Transformation;
import android.widget.Gallery;
import android.widget.ImageView;

public class GalleryFlow extends Gallery {

	private Camera mCamera = new Camera();//�����
    private int mMaxRotationAngle = 60;//���ת���Ƕ�
    private int mMaxZoom = -300;////�������ֵ
    private int mCoveflowCenter;//�뾶ֵ
    public GalleryFlow(Context context) {
        super(context);
        //֧��ת�� ,ִ��getChildStaticTransformation����
        this.setStaticTransformationsEnabled(true);
    }
    public GalleryFlow(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.setStaticTransformationsEnabled(true);
    }
    public GalleryFlow(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        this.setStaticTransformationsEnabled(true);
    }
    public int getMaxRotationAngle() {
        return mMaxRotationAngle;
    }
    public void setMaxRotationAngle(int maxRotationAngle) {
        mMaxRotationAngle = maxRotationAngle;
    }
    public int getMaxZoom() {
        return mMaxZoom;
    }
    public void setMaxZoom(int maxZoom) {
        mMaxZoom = maxZoom;
    }
    private int getCenterOfCoverflow() {
        return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2
                        + getPaddingLeft();
    }
    private static int getCenterOfView(View view) {
        System.out.println("view left :"+view.getLeft());
        System.out.println("view width :"+view.getWidth());
        return view.getLeft() + view.getWidth() / 2;
    }
   
   
   //����gallery��ÿ��ͼƬ����ת(��д��gallery�з���)
    @Override
    protected boolean getChildStaticTransformation(View child, Transformation t) { 
        //ȡ�õ�ǰ��view�İ뾶ֵ
        final int childCenter = getCenterOfView(child);
        System.out.println("childCenter��"+childCenter);
        final int childWidth = child.getWidth();
        //��ת�Ƕ�
        int rotationAngle = 0;
        //����ת��״̬
        t.clear();
        //����ת������
        t.setTransformationType(Transformation.TYPE_MATRIX);
        //���ͼƬλ������λ�ò���Ҫ������ת
        if (childCenter == mCoveflowCenter) {
            transformImageBitmap((ImageView) child, t, 0);
        } else {
            //����ͼƬ��gallery�е�λ��������ͼƬ����ת�Ƕ�
            rotationAngle = (int) (((float) (mCoveflowCenter - childCenter) / childWidth) * mMaxRotationAngle);
            System.out.println("rotationAngle:" +rotationAngle);
            //�����ת�ǶȾ���ֵ���������ת�Ƕȷ��أ�-mMaxRotationAngle��mMaxRotationAngle;��
            if (Math.abs(rotationAngle) > mMaxRotationAngle) {
                rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle;
            }
            transformImageBitmap((ImageView) child, t, rotationAngle);
        }
        return true;
    }
    
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        mCoveflowCenter = getCenterOfCoverflow();
        super.onSizeChanged(w, h, oldw, oldh);
    }
    
    private void transformImageBitmap(ImageView child, Transformation t,
                    int rotationAngle) {
        //���������
        mCamera.save();
        final Matrix imageMatrix = t.getMatrix();
        //ͼƬ�߶�
        final int imageHeight = child.getLayoutParams().height;
        //ͼƬ���
        final int imageWidth = child.getLayoutParams().width;
       
        //������ת�Ƕȵľ���ֵ
        final int rotation = Math.abs(rotationAngle);
       
        // ��Z���������ƶ�camera���ӽǣ�ʵ��Ч��Ϊ�Ŵ�ͼƬ��
        // �����Y�����ƶ�����ͼƬ�����ƶ���X���϶�ӦͼƬ�����ƶ���
        mCamera.translate(0.0f, 10.0f, 300.0f);// �����ֵԽ��ͼƬԽ��С
        // As the angle of the view gets less, zoom in
        if (rotation < mMaxRotationAngle) {
            float zoomAmount = (float) (mMaxZoom + (rotation * 1.5));
            mCamera.translate(0.0f, 0.0f, zoomAmount);
        }
        // ��Y������ת����ӦͼƬ�������﷭ת��
        // �����X������ת�����ӦͼƬ�������﷭ת��
        mCamera.rotateY(rotationAngle);
        mCamera.getMatrix(imageMatrix);
        imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));
        imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));
        mCamera.restore();
    }

}