如何在整个屏幕上在画布上绘制位图？

Question

在我的应用程序中，我需要在整个屏幕上绘制一个位图。出于某种原因，当我绘制位图时，只有部分位图加载在屏幕的一部分上。换句话说，屏幕上并未显示全部图像。下面是一段我的代码是我画的位图：

  byte[]byteArray=getIntent().getByteArrayExtra("image"); 
      Bitmap tmp=BitmapFactory.decodeByteArray(byteArray,0,byteArray.length); 


      operation = Bitmap.createBitmap(tmp.getWidth(), tmp.getHeight(), Bitmap.Config.ARGB_8888); 
      Canvas c = new Canvas(operation); 
      Paint paint = new Paint(); 
      tmp.setDensity(c.getDensity()); 

      c.drawBitmap(tmp, 0f, 0f, paint); 
      tmp.recycle(); 

和：

private void drawOverlays() { 
    Canvas c = null; 
    try { 
     c = holder.lockCanvas(null); 
     synchronized (holder) { 
      if (c != null) 
       c.drawBitmap(operation, 0, 0, null); 
     } 
    } catch (Exception e) { 
     Log.e("SurfaceView", "Error drawing frame", e); 
    } finally { 
     // do this in a finally so that if an exception is thrown 
     // during the above, we don't leave the Surface in an 
     // inconsistent state 
     if (c != null) { 
      holder.unlockCanvasAndPost(c); 
     } 
    } 
} 

Answer 1

对于您需要得到宽度以及设备的高度，然后缩放图像到尺寸和显示它在画布上。

这是您的代码的修改。

//add this code before your code 
Display display = getWindowManager().getDefaultDisplay(); 
Point size = new Point(); 
display.getSize(size); 
int width = size.x; 
int height = size.y; 

//your code with modification 
byte[]byteArray=getIntent().getByteArrayExtra("image"); 
Bitmap tmp=BitmapFactory.decodeByteArray(byteArray,0,byteArray.length); 
operation = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); 
Canvas c = new Canvas(operation); 
Paint paint = new Paint(); 
tmp.setDensity(c.getDensity()); 
c.drawBitmap(tmp, 0f, 0f, paint); 
tmp.recycle(); 

现在它会填满整个屏幕，确保您将画布应用于整个屏幕。