矩阵不能被修改

Question

我实现使用给定的代码封面流在http://www.inter-fuser.com/2010/01/android-coverflow-widget.html

的问题是，在该代码的ImageView用作封面流项。我需要一个自定义的UI（里面的LinearLayout ImageView的和TextView中）在我的应用程序，所以我创建了一个新的适配器和CoverFlow.java我changd所有的ImageView查看，但这种崩溃的广告应用程式，并显示以下错误

03-31 18:32:36.486: E/AndroidRuntime(14839): FATAL EXCEPTION: main 
03-31 18:32:36.486: E/AndroidRuntime(14839): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.cisco.rnd.ytdeom/com.cisco.rnd.carousal.absspinner.CoverFlowAbsActivity}: java.lang.IllegalStateException: Matrix can not be modified 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.ActivityThread.access$700(ActivityThread.java:140) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.os.Handler.dispatchMessage(Handler.java:99) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.os.Looper.loop(Looper.java:137) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.ActivityThread.main(ActivityThread.java:4921) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at java.lang.reflect.Method.invokeNative(Native Method) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at java.lang.reflect.Method.invoke(Method.java:511) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at dalvik.system.NativeStart.main(Native Method) 
03-31 18:32:36.486: E/AndroidRuntime(14839): Caused by: java.lang.IllegalStateException: Matrix can not be modified 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.graphics.Matrix$1.oops(Matrix.java:43) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.graphics.Matrix$1.preTranslate(Matrix.java:109) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.cisco.rnd.carousal.absspinner.CoverFlow.transformImageBitmap(CoverFlow.java:806) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.cisco.rnd.carousal.absspinner.CoverFlow.makeAndAddView(CoverFlow.java:861) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.cisco.rnd.carousal.absspinner.CoverFlow.layout(CoverFlow.java:668) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.cisco.rnd.carousal.absspinner.CoverAbsSpinner.setSelectionInt(CoverAbsSpinner.java:315) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.cisco.rnd.carousal.absspinner.CoverAbsSpinner.setSelection(CoverAbsSpinner.java:291) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at com.cisco.rnd.carousal.absspinner.CoverFlowAbsActivity.onCreate(CoverFlowAbsActivity.java:52) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.Activity.performCreate(Activity.java:5188) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094) 
03-31 18:32:36.486: E/AndroidRuntime(14839): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074) 
03-31 18:32:36.486: E/AndroidRuntime(14839): ... 11 more 

我的代码是

static private void transformImageBitmap(View imageView,int offset, 
     boolean initialLayout, int rotationAngle) { 
    Camera camera = new Camera(); 
    Matrix imageMatrix; 
    int imageHeight; 
    int imageWidth; 
    int bitMapHeight; 
    int bitMapWidth; 
    float scaleWidth; 
    float scaleHeight; 

    imageMatrix = imageView.getMatrix(); 

    camera.translate(0.0f, 0.0f, 100.0f); 

    if (initialLayout) { 
     if(offset < 0) {    
      camera.rotateY(rotationAngle); 
     } else if (offset > 0) { 
      camera.rotateY(-rotationAngle); 
     } else { 
      //Just zoom in a little for the central View 
      camera.translate(0.0f, 0.0f, mMaxZoom); 

     } 
    } else { 
     if (offset == 0) { 
      //As the angle of the view gets less, zoom in 
      int rotation = Math.abs(rotationAngle); 
      if (rotation < 30) { 
       float zoomAmount = (float) (mMaxZoom + (rotation * 1.5)); 
       camera.translate(0.0f, 0.0f, zoomAmount);     
      } 
      camera.rotateY(rotationAngle); 
     } 
    } 

    camera.getMatrix(imageMatrix);    

    imageHeight = imageView.getLayoutParams().height; 
    imageWidth = imageView.getLayoutParams().width; 
    bitMapHeight = imageView.getBackground().getIntrinsicHeight(); 
    bitMapWidth = imageView.getBackground().getIntrinsicWidth(); 
    scaleHeight = ((float) imageHeight)/bitMapHeight; 
    scaleWidth = ((float) imageWidth)/bitMapWidth; 

    imageMatrix.preTranslate(-(imageWidth/2), -(imageHeight/2)); 
    imageMatrix.preScale(scaleWidth, scaleHeight); 
    imageMatrix.postTranslate((imageWidth/2), (imageHeight/2)); 

} 

请帮助...

Answer 1

提供的堆栈跟踪说，你不能碰imageMatrix，所以你应该创建现有矩阵的深层副本和做大规模&翻译业务该新代码 用以下代码替换您的代码的最后三行：

Matrix newMatrix = new Matrix(); 
newMatrix.set(imageMatrix); 

newMatrix.preTranslate(-(imageWidth/2), -(imageHeight/2)); 
newMatrix.preScale(scaleWidth, scaleHeight); 
newMatrix.postTranslate((imageWidth/2), (imageHeight/2));