android 区域截屏

场景：Android兑现指定区域截屏的实现

Android实现指定区域截屏的实现

其实实现方式很简单，首先我们需要做的就是截取整个屏幕生成一个bitmap对象

View view = activity.getWindow().getDecorView();
view.setDrawingCacheEnabled(true);
view.buildDrawingCache();
bitmap = view.getDrawingCache();

 然后我们需呀计算出我们选定区域的坐标点，注意正选和反选的计算方式不同 ，

public boolean onTouch(View v, MotionEvent event) {
     if(event.getAction() == MotionEvent.ACTION_DOWN){
			x = 0;
			y = 0;
			width = 0;
			height = 0;
			x = (int) event.getX();
			y = (int) event.getY();
		}
      if(event.getAction() == MotionEvent.ACTION_MOVE){
			m = (int) event.getX();
			n = (int) event.getY();
			myView.setSeat(x, y, m, n);
			myView.postInvalidate();
		}
      if(event.getAction() == MotionEvent.ACTION_UP){
	if(event.getX()>x){
	     width = (int)event.getX()-x;
	}else{
	     width = (int)(x-event.getX());
	      x = (int) event.getX();
	}
                 if(event.getY()>y){
	     height = (int) event.getY()-y;
	 }else{
	     height = (int)(y-event.getY());
	      y = (int) event.getY();
	}
	image2.setImageBitmap(getBitmap(this));
		}
	if(myView.isSign()){
	     return false;
	}else{
	      return true;
	}
}

 

然后为我们计算出来的坐标区域添加选中效果

 

protected void onDraw(Canvas canvas) {
         if(sign){
	paint.setColor(Color.TRANSPARENT);
         }else{
	paint.setColor(Color.RED);
	paint.setAlpha(80);
	canvas.drawRect(new Rect(x, y, m, n), paint);
           }
	super.onDraw(canvas);
}

 

最后生成我们需要的图片展示出来，顺便保存到SD卡下一张。

Rect frame = new Rect();
      activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
      int toHeight = frame.top;
      bitmap = Bitmap.createBitmap(bitmap, x, y+2*toHeight, width, height);
      try {
	FileOutputStream fout = new FileOutputStream("mnt/sdcard/test.png");
	bitmap.compress(Bitmap.CompressFormat.PNG, 100, fout);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		view.setDrawingCacheEnabled(false);