Android实现CoverFlow效果 一

先上一张效果图：
 

上代码，看了代码什么都明白

CoverFlow从Gallery继承过来

002
003 import android.content.Context;
004 import android.graphics.Camera;
005 import android.graphics.Matrix;
006 import android.util.AttributeSet;
007 import android.view.View;
008 import android.view.animation.Transformation;
009 import android.widget.Gallery;
010 import android.widget.ImageView;
011
012 public class CoverFlow extends Gallery {
013
014     private Camera mCamera = new Camera();
015     private int mMaxRotationAngle = 50;
016     private int mMaxZoom = -380;
017     private int mCoveflowCenter;
018     private boolean mAlphaMode = true;
019     private boolean mCircleMode = false;
020
021     public CoverFlow(Context context) {
022         super(context);
023         this.setStaticTransformationsEnabled(true);
024     }
025
026     public CoverFlow(Context context, AttributeSet attrs) {
027         super(context, attrs);
028         this.setStaticTransformationsEnabled(true);
029     }
030
031     public CoverFlow(Context context, AttributeSet attrs, int defStyle) {
032         super(context, attrs, defStyle);
033         this.setStaticTransformationsEnabled(true);
034     }
035
036     public int getMaxRotationAngle() {
037         return mMaxRotationAngle;
038     }
039
040     public void setMaxRotationAngle(int maxRotationAngle) {
041         mMaxRotationAngle = maxRotationAngle;
042     }
043
044     public boolean getCircleMode() {
045         return mCircleMode;
046     }
047
048     public void setCircleMode(boolean isCircle) {
049         mCircleMode = isCircle;
050     }
051
052     public boolean getAlphaMode() {
053         return mAlphaMode;
054     }
055
056     public void setAlphaMode(boolean isAlpha) {
057         mAlphaMode = isAlpha;
058     }
059
060     public int getMaxZoom() {
061         return mMaxZoom;
062     }
063
064     public void setMaxZoom(int maxZoom) {
065         mMaxZoom = maxZoom;
066     }
067
068     private int getCenterOfCoverflow() {
069         return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2
070                 + getPaddingLeft();
071     }
072
073     private static int getCenterOfView(View view) {
074         return view.getLeft() + view.getWidth() / 2;
075     }
076
077     protected boolean getChildStaticTransformation(View child, Transformation t) {
078         final int childCenter = getCenterOfView(child);
079         final int childWidth = child.getWidth();
080         int rotationAngle = 0;
081         t.clear();
082         t.setTransformationType(Transformation.TYPE_MATRIX);
083         if (childCenter == mCoveflowCenter) {
084             transformImageBitmap((ImageView) child, t, 0);
085         } else {
086             rotationAngle = (int) (((float) (mCoveflowCenter - childCenter) / childWidth) * mMaxRotationAngle);
087             if (Math.abs(rotationAngle) > mMaxRotationAngle) {
088                 rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle
089                         : mMaxRotationAngle;
090             }
091             transformImageBitmap((ImageView) child, t, rotationAngle);
092         }
093         return true;
094     }
095
096     /**
097      * 这就是所谓的在大小的布局时,这一观点已经发生了改变。如果 你只是添加到视图层次,有人叫你旧的观念 价值观为0。
098      *
099      * @param w
100      *            Current width of this view.
101      * @param h
102      *            Current height of this view.
103      * @param oldw
104      *            Old width of this view.
105      * @param oldh
106      *            Old height of this view.
107      */
108     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
109         mCoveflowCenter = getCenterOfCoverflow();
110         super.onSizeChanged(w, h, oldw, oldh);
111     }
112
113     /**
114      * 把图像位图的角度通过
115      *
116      * @param imageView
117      *            ImageView the ImageView whose bitmap we want to rotate
118      * @param t
119      *            transformation
120      * @param rotationAngle
121      *            the Angle by which to rotate the Bitmap
122      */
123     private void transformImageBitmap(ImageView child, Transformation t,
124             int rotationAngle) {
125         mCamera.save();
126         final Matrix imageMatrix = t.getMatrix();
127         final int imageHeight = child.getLayoutParams().height;
128         final int imageWidth = child.getLayoutParams().width;
129         final int rotation = Math.abs(rotationAngle);
130         mCamera.translate(0.0f, 0.0f, 100.0f);
131
132         // 如视图的角度更少,放大
133         if (rotation <= mMaxRotationAngle) {
134             float zoomAmount = (float) (mMaxZoom + (rotation * 1.5));
135             mCamera.translate(0.0f, 0.0f, zoomAmount);
136             if (mCircleMode) {
137                 if (rotation < 40)
138                     mCamera.translate(0.0f, 155, 0.0f);
139                 else
140                     mCamera.translate(0.0f, (255 - rotation * 2.5f), 0.0f);
141             }
142             if (mAlphaMode) {
143                 ((ImageView) (child)).setAlpha((int) (255 - rotation * 2.5));
144             }
145         }
146         mCamera.rotateY(rotationAngle);
147         mCamera.getMatrix(imageMatrix);
148         imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));
149         imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));
150         mCamera.restore();
151     }
152 }