未在自定义视图中绘制位图

Question

我有一个应用程序可以从SD卡上的相机和商店中捕获图片。我创建了一个自定义视图，将该图像读入一个数组并从中创建一个位图。我使用Bitmap.createBitmap（w，h，config）创建了另一个位图，以便我有一个可变副本。在我看来的onDraw位图没有被绘制，只是一个黑色的图像显示。任何想法为什么位图不被绘制？感谢

BitmapFactory.Options bfo = new BitmapFactory.Options(); 
      bfo.inSampleSize = 1; 
      bm = BitmapFactory.decodeByteArray(imageArray, 0, imageArray.length, bfo); 
     bgr = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig()); 

，并在我的onDraw（）

@Override 
     public void onDraw(Canvas canvas){ 
      super.onDraw(canvas); 

      Log.e(TAG, "***********BITMAP bm = "+bm.toString()); 
      canvas.drawBitmap(bgr, 0, 0, null); 

[编辑]

public class LoadPic2 extends Activity { 

    private static final String TAG = "*********LOADPIC"; 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     Log.e(TAG, "***********inside oncreate about to set contentview = "); 
     setContentView(new TouchView(this)); 


    } 

    class TouchView extends View{ 


     private File tempFile; 
     private byte[] imageArray; 
     Bitmap bgr; 
     Bitmap bm; 
     Bitmap overlayRed; 
     Bitmap overlayBlue; 
     Paint pTouch; 
     int X = -100; 
     int Y = -100; 
     Canvas c2; 

     public TouchView(Context context) { 
      super(context); 

      Log.e(TAG, "***********inside Touchview constructor = "); 

      tempFile = new File(Environment.getExternalStorageDirectory(). 
        getAbsolutePath() + "/"+"image.jpg"); 

      imageArray = new byte[(int)tempFile.length()]; 

     try{ 

      InputStream is = new FileInputStream(tempFile); 
       BufferedInputStream bis = new BufferedInputStream(is); 
       DataInputStream dis = new DataInputStream(bis); 


       int i = 0; 

       while (dis.available() > 0) { 
       imageArray[i] = dis.readByte(); 
       i++; 
       } 

       dis.close(); 

     } catch (Exception e) { 

        e.printStackTrace(); 
       } 
      Log.e(TAG, "***********end of touchview imagearray = "+ imageArray.length); 
      BitmapFactory.Options bfo = new BitmapFactory.Options(); 
      bfo.inSampleSize = 1; 
      bm = BitmapFactory.decodeByteArray(imageArray, 0, imageArray.length, bfo); 
      bgr = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig()); 
      bgr = bm.copy(bm.getConfig(), true); 
      // Log.e(TAG, "***********bgr = "+bgr.toString()+bgr); 

      overlayRed = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig()); 
      overlayRed.eraseColor(Color.RED); 
      overlayBlue = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig()); 
      overlayBlue.eraseColor(Color.BLUE); 
      // overlayRed = BitmapFactory.decodeResource(getResources(),R.drawable.icon); 
      // overlayBlue = BitmapFactory.decodeResource(getResources(),R.drawable.icon).copy(Config.ARGB_8888, true); 

      c2 = new Canvas(overlayBlue);//overlay 

      pTouch = new Paint(Paint.ANTI_ALIAS_FLAG);   
      pTouch.setXfermode(new PorterDuffXfermode(Mode.SRC_OUT)); 
      pTouch.setColor(Color.TRANSPARENT); 
      pTouch.setMaskFilter(new BlurMaskFilter(15, Blur.NORMAL)); 

      Log.e(TAG, "***********end of touchview constructor = "+bm.toString()); 

     } 

     @Override 
     public boolean onTouchEvent(MotionEvent ev) { 

      switch (ev.getAction()) { 

       case MotionEvent.ACTION_DOWN: { 

        X = (int) ev.getX(); 
        Y = (int) ev.getY(); 
        invalidate(); 

        break; 
       } 

       case MotionEvent.ACTION_MOVE: { 

         X = (int) ev.getX(); 
         Y = (int) ev.getY(); 
         invalidate(); 
         break; 

       }   

       case MotionEvent.ACTION_UP: 

        break; 

      } 
      return true; 
     } 


     @Override 
     public void onDraw(Canvas canvas){ 
      super.onDraw(canvas); 

      Log.e(TAG, "***********BITMAP bm = "+bm.toString()); 
      canvas.drawBitmap(bgr, 0, 0, null); 
      c2.drawBitmap(overlayRed, 0, 0, null); //exclude this line to show all as you draw 
      c2.drawCircle(X, Y, 80,pTouch); 
      canvas.drawBitmap(overlayBlue, 0, 0, null); 



     } 


    } 




} 

Answer 1

你正在创建同样大小的一个全新的可变Bitmap，不使一个可变的副本。

尝试使用Bitmap#copy：

bgr = bm.copy(bm.getConfig(), true); 

的true参数表明你想要一个可变的副本。