Android系列之淺談Android 3D旋轉

最近和一哥們在聊Android的3D旋轉效果的技術實現的事情，今天正好有點時間就把技術細節寫了出來

在ANDROID中實現3D旋轉直接使用animation配合camera就可以實現，在apidemo裡就有這樣的實例

我們首先做一個繼承animation的類Rotate3d.java

  1 public class Rotate3d extends Animation {   
  2     private float mFromDegree;   
  3     private float mToDegree;   
  4     private float mCenterX;   
  5     private float mCenterY;   
  6     private float mLeft;   
  7     private float mTop;   
  8     private Camera mCamera;   
  9     private static final String TAG = "Rotate3d";   
 10   
 11     public Rotate3d(float fromDegree, float toDegree, float left, float top,   
 12             float centerX, float centerY) {   
 13         this.mFromDegree = fromDegree;   
 14         this.mToDegree = toDegree;   
 15         this.mLeft = left;   
 16         this.mTop = top;   
 17         this.mCenterX = centerX;   
 18         this.mCenterY = centerY;   
 19   
 20     }   
 21   
 22     @Override   
 23     public void initialize(int width, int height, int parentWidth,   
 24             int parentHeight) {   
 25         super.initialize(width, height, parentWidth, parentHeight);   
 26         mCamera = new Camera();   
 27     }   
 28   
 29     @Override   
 30     protected void applyTransformation(float interpolatedTime, Transformation t) {   
 31         final float FromDegree = mFromDegree;   
 32         float degrees = FromDegree + (mToDegree - mFromDegree)   
 33                 * interpolatedTime;   
 34         final float centerX = mCenterX;   
 35         final float centerY = mCenterY;   
 36         final Matrix matrix = t.getMatrix();   
 37   
 38         if (degrees <= -76.0f) {   
 39              degrees = -90.0f;   
 40              mCamera.save();   
 41              mCamera.rotateY(degrees);   
 42              mCamera.getMatrix(matrix);   
 43              mCamera.restore();   
 44         } else if(degrees >=76.0f){   
 45             degrees = 90.0f;   
 46             mCamera.save();   
 47             mCamera.rotateY(degrees);   
 48             mCamera.getMatrix(matrix);   
 49             mCamera.restore();   
 50         }else{   
 51             mCamera.save();   
 52                        //這裡很重要哦。   
 53              mCamera.translate(0, 0, centerX);   
 54             mCamera.rotateY(degrees);   
 55             mCamera.translate(0, 0, -centerX);   
 56             mCamera.getMatrix(matrix);   
 57             mCamera.restore();   
 58         }   
 59   
 60         matrix.preTranslate(-centerX, -centerY);   
 61         matrix.postTranslate(centerX, centerY);   
 62     }   
 63 }  
 64 
 65  public class Rotate3d extends Animation {
 66     private float mFromDegree;
 67     private float mToDegree;
 68     private float mCenterX;
 69     private float mCenterY;
 70     private float mLeft;
 71     private float mTop;
 72     private Camera mCamera;
 73     private static final String TAG = "Rotate3d";
 74 
 75     public Rotate3d(float fromDegree, float toDegree, float left, float top,
 76             float centerX, float centerY) {
 77         this.mFromDegree = fromDegree;
 78         this.mToDegree = toDegree;
 79         this.mLeft = left;
 80         this.mTop = top;
 81         this.mCenterX = centerX;
 82         this.mCenterY = centerY;
 83 
 84     }
 85 
 86     @Override
 87     public void initialize(int width, int height, int parentWidth,
 88             int parentHeight) {
 89         super.initialize(width, height, parentWidth, parentHeight);
 90         mCamera = new Camera();
 91     }
 92 
 93     @Override
 94     protected void applyTransformation(float interpolatedTime, Transformation t) {
 95         final float FromDegree = mFromDegree;
 96         float degrees = FromDegree + (mToDegree - mFromDegree)
 97                 * interpolatedTime;
 98         final float centerX = mCenterX;
 99         final float centerY = mCenterY;
100         final Matrix matrix = t.getMatrix();
101 
102         if (degrees <= -76.0f) {
103              degrees = -90.0f;
104              mCamera.save();
105              mCamera.rotateY(degrees);
106              mCamera.getMatrix(matrix);
107              mCamera.restore();
108         } else if(degrees >=76.0f){
109             degrees = 90.0f;
110             mCamera.save();
111             mCamera.rotateY(degrees);
112             mCamera.getMatrix(matrix);
113             mCamera.restore();
114         }else{
115             mCamera.save();
116                        //這裡很重要哦。
117              mCamera.translate(0, 0, centerX);
118             mCamera.rotateY(degrees);
119             mCamera.translate(0, 0, -centerX);
120             mCamera.getMatrix(matrix);
121             mCamera.restore();
122         }
123 
124         matrix.preTranslate(-centerX, -centerY);
125         matrix.postTranslate(centerX, centerY);
126     }
127 } 
128 
129  

有了這個類一切都會變得簡單的，接著只要在activity中寫兩個Rotate3d的對象，讓兩個view,分別做這兩個對象的animation就好了;

 1 //下面兩句很關鍵哦， 
 2         Rotate3d leftAnimation = new Rotate3d(-0, -90, 0, 0, mCenterX, mCenterY);   
 3         Rotate3d rightAnimation = new Rotate3d(-0+90, -90+90, 0.0f, 0.0f, mCenterX, mCenterY);   
 4   
 5         leftAnimation.setFillAfter(true);   
 6         leftAnimation.setDuration(1000);   
 7         rightAnimation.setFillAfter(true);   
 8         rightAnimation.setDuration(1000);   
 9   
10         mImageView1.startAnimation(leftAnimation);   
11         mImageView2.startAnimation(rightAnimation);  
12

最後就是還要寫一下mImageView1,mImageView2的xml,

 1 <?xml version="1.0" encoding="utf-8"?>  
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
 3     android:orientation="vertical"  
 4     android:layout_width="fill_parent"  
 5     android:layout_height="wrap_content"  
 6     >  
 7   
 8     <FrameLayout  
 9         android:layout_width="fill_parent"  
10         android:layout_height="fill_parent">  
11   
12                    <ImageView  
13                     android:id="@+id/image1"  
14                     android:layout_gravity="center_horizontal"  
15                     android:layout_width="fill_parent"  
16                     android:layout_height="wrap_content"  
17                     android:src="@drawable/image1"  
18                     />  
19                    <ImageView  
20                     android:id="@+id/image2"  
21                     android:background="#ffff0000"  
22                     android:layout_gravity="center_horizontal"  
23                     android:layout_width="fill_parent"  
24                     android:layout_height="wrap_content"  
25                     android:src="@drawable/image2"  
26                     />  
27   
28     </FrameLayout>  
29 </LinearLayout>  

轉自：http://www.cnblogs.com/jk1001/archive/2010/07/28/1787009.html