Android兑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;	}}

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然后为我们计算出来的坐标区域添加选中效果

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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);}

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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);

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