以前面試的時候面試官問過我會不會寫標尺工具，我沒做過呀，然後胡亂的說什麼畫布，ondraw繪製。。然後就沒有然後了--！，現在想想真的有點囧。所以今天我試了下自己畫刻度盤，不是很難，只有方法對了，輕輕鬆鬆。。大神勿噴，這是菜鳥的日常（高手退散退散。。巴拉巴拉能量**>_<**）

/**
 * 第一步
 */
@Override
protected void onMeasure(int 
 
widthMeasureSpec, int heightMeasureSpec) {
    int width =measureDim(widthMeasureSpec,150);
    int height = measureDim(heightMeasureSpec,150);
    if (width!=height){
        width=Math.max(width,height);
        height =width;
    }
    setMeasuredDimension(width,height);
    initView();
}

public int 
 
measureDim(int Spec,int defultsize){
    int result;
    int mode = MeasureSpec.getMode(Spec);
    int size = MeasureSpec.getSize(Spec);
    if (mode==MeasureSpec.EXACTLY){
        result =size;
    }else {
        result =defultsize;
        if (mode==MeasureSpec.AT_MOST){
            result =Math.min
 
(size,defultsize);
        }
    }
    return result;

}

public void initView(){
   cPaint = new Paint();
    cPaint.setAntiAlias(true);
    cPaint.setColor(Color.BLUE);
    cPaint.setStyle(Paint.Style.STROKE);
    cPaint.setStrokeWidth(2);
    cPaint.setTextSize(12);
    list = new ArrayList<>();

}

@Override
protected void onDraw(Canvas canvas) {
    radio =getMeasuredWidth()/2-20;
    canvas.drawCircle(radio,radio,radio,cPaint);
    canvas.drawPoint(radio,radio,cPaint);
    scaleCount(canvas);
}

/**
 * 錶盤刻度的計算,繪製
 */
private void scaleCount(Canvas canvas){
    double startx;
    double starty;
    double endx;
    double endy;
    for (int i=0;i<60;i++){
        if (i%5==0){
            endx= Math.sin( Math.toRadians(i*6))*(radio/2+10)+radio;
            endy = radio-Math.cos( Math.toRadians(i*6))*(radio/2+10);

            /*
            這段繪製刻度值有點問題字歪的 ，以後改善
             */
         /*
            double textX = Math.sin( Math.toRadians(i*6))*(radio/2+9)+radio;
            double textY = radio-Math.cos( Math.toRadians(i*6))*(radio/2+9);
            canvas.drawText((i/5==0?12:i/5)+"",(float) textX,(float)textY,cPaint);*/
        }else {
            endx= Math.sin( Math.toRadians(i*6))*(radio-10)+radio;
            endy = radio-Math.cos( Math.toRadians(i*6))*(radio-10);
        }
        startx  =Math.sin( Math.toRadians(i*6))*(radio)+radio;
        starty  = radio-Math.cos( Math.toRadians(i*6))*(radio);
        Line line = new Line(startx,starty,endx,endy);
        list.add(line);
    }
    drawLine(canvas);
}

public void drawLine(Canvas canvas){
    cPaint.reset();
    cPaint.setColor(Color.BLACK);
    cPaint.setStyle(Paint.Style.FILL);
    cPaint.setAntiAlias(true);
    for (int i=0;i<list.size();i++){
        canvas.drawLine((float) list.get(i).getStartx(),(float)list.get(i).getStarty(),(float)list.get(i).getEndx(),
                (float)list.get(i).getEndy(),cPaint);
    }
}