如何旋轉位圖的像素

Question

我想在Android中將位圖旋轉90度。我不想要一個新的實例。有什麼辦法可以解決這個問題嗎？我有一個想法：只需旋轉位圖的像素。但我做不到。

temp = Bitmap.createBitmap(temp, 0, 0, w, h, matrix, false);

Answer 1

這工作：

http://warting.github.com/AndroidBitmapRotate/

public class RotateBitmapActivity extends Activity { 

    ImageView iv; 
    private Bitmap bitmap; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

     bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher); 
     iv = (ImageView) findViewById(R.id.ImageView01); 

     findViewById(R.id.left).setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       rotate(-90F); 
      } 
     }); 

     findViewById(R.id.right).setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       rotate(90F); 
      } 
     }); 
    } 

    private void rotate(float degrees) { 

     Matrix rotateMatrix = new Matrix(); 
     rotateMatrix.postRotate(degrees); 

     bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), rotateMatrix, true); 
     iv.setImageBitmap(bitmap); 
    } 
}