在屏幕中绘制xy轴刻度便于参考

public static void drawMark(Canvas canvas){
    	paint.setColor(Color.BLUE);
    	paint.setStyle(Paint.Style.STROKE);
    	paint.setAntiAlias(true);//去锯齿
    	paint.setTextSize(20);

    	// x 轴
    	//canvas.drawLine(0, 0, 800*3/2, 0, paint);
    	// x 轴刻度 每个刻度100
    	for(int i=0; i<14; i++){
    		canvas.drawLine(100*i, 0, 100*i, 15, paint);
    		canvas.drawText(""+i, 100*i, 20, paint);
    	}
    	// y 轴
    	//canvas.drawLine(5, 5, 800*3/2, 5, paint);
    	// y 轴刻度
    	for(int i=0; i<8; i++){
    		canvas.drawLine(0, 100*i, 15, 100*i, paint);
    		canvas.drawText(""+i, 5, 100*i+10, paint);
    	}
	}