本文實例為大家分享了Android實現時鐘效果的具體代碼，供大家參考，具體內容如下
先看下最終的效果
開始實現
新建一個ClockView集成View
public class ClockView extends View { }先重寫onMeasure方法，這里要先說一下View的測量模式，一共有三種：
1、EXACTLY
即精確值模式，當我們將控件的layout_width屬性或layout_height屬性指定為具體數值時，比如android:layout_width="100dp"，或者指定為math_parent屬性時（占據父View的大小），系統使用的是EXACTLY模式。
2、AT_MOST
即最大值模式，當控件的layout_width屬性或layout_height屬性指定為wrap_content時，控件大小一般隨著控件的子控件或內容的變化而變化，此時控件的尺寸只要不超過父控件允許的最大尺寸即可。
3、UNSPECIFIED
這個屬性比較奇怪――它不指定其大小測量模式，View想多大就多大，通常情況下在繪制自定義View時才會使用。
因為View的onMeasure方法只支持EXACTLY模式，當layout_width和layout_height為wrap_content時，View的大小就顯得很奇怪了，如下圖。
所以我們重寫一下onMeasure方法可以指定View width、height的最小值
/** * 當布局為wrap_content時設置默認長寬 * @param widthMeasureSpec * @param heightMeasureSpec */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(measure(widthMeasureSpec), measure(heightMeasureSpec)); } private int measure(int origin){ int result = DEFAULT_MIN_WIDTH; int specMode = MeasureSpec.getMode(origin); int specSize = MeasureSpec.getSize(origin); if(specMode == MeasureSpec.EXACTLY){ result = specSize; }else{ if(specMode == MeasureSpec.AT_MOST){ result = Math.min(result, specSize); } } return result; }下面就是最重要的重寫onDraw方法來繪制表盤、刻度、指針……，大致流程如下
1、畫表盤，用drawCircle繪制一個圓作為表盤, 圓心坐標為(getWidth()/2, getHeight()/2)，半徑為Math.min(getHeight()/2, getWidth()/2)。
//畫外圓float borderWidth = DEFAULT_BORDER_WIDTH;Paint paintCircle = new Paint();paintCircle.setStyle(Paint.Style.STROKE);paintCircle.setAntiAlias(true);paintCircle.setStrokeWidth(borderWidth);canvas.drawCircle(getWidth() / 2, getHeight() / 2, Math.min(getHeight() / 2, getWidth() / 2) - borderWidth / 2, paintCircle);
2、畫刻度線，在這里我們可以利用一個`canvas.rotate'方法就可以不用計算角度了
//畫刻度線float degreeLength = 0f;Paint paintDegree = new Paint();paintDegree.setAntiAlias(true);for(int i=0;i<60;i++){ if(i % 5 == 0){ paintDegree.setStrokeWidth(6); degreeLength = DEFAULT_LONG_DEGREE_LENGTH; }else{ paintDegree.setStrokeWidth(3); degreeLength = DEFAULT_SHORT_DEGREE_LENGTH; } canvas.drawLine(getWidth()/2, Math.abs(getWidth()/2 - getHeight()/2), getWidth()/2, Math.abs(getWidth()/2 - getHeight()/2) + degreeLength, paintDegree); canvas.rotate(360/60, getWidth()/2, getHeight()/2);}3、畫刻度上的數字
//刻度數字int degressNumberSize = 30;canvas.translate(getWidth() / 2, getHeight() / 2);Paint paintDegreeNumber = new Paint();paintDegreeNumber.setTextAlign(Paint.Align.CENTER);paintDegreeNumber.setTextSize(degressNumberSize);paintDegreeNumber.setFakeBoldText(true);for(int i=0;i<12;i++){ float[] temp = calculatePoint((i+1)*30, r - DEFAULT_LONG_DEGREE_LENGTH - degressNumberSize/2 - 15); canvas.drawText((i+1)+"", temp[2], temp[3] + degressNumberSize/2-6, paintDegreeNumber);}/** * 根據角度和長度計算線段的起點和終點的坐標 * @param angle * @param length * @return */private float[] calculatePoint(float angle, float length){ float[] points = new float[4]; if(angle <= 90f){ points[0] = -(float) Math.sin(angle*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[1] = (float) Math.cos(angle*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[2] = (float) Math.sin(angle*Math.PI/180) * length; points[3] = -(float) Math.cos(angle*Math.PI/180) * length; }else if(angle <= 180f){ points[0] = -(float) Math.cos((angle-90)*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[1] = -(float) Math.sin((angle-90)*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[2] = (float) Math.cos((angle-90)*Math.PI/180) * length; points[3] = (float) Math.sin((angle-90)*Math.PI/180) * length; }else if(angle <= 270f){ points[0] = (float) Math.sin((angle-180)*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[1] = -(float) Math.cos((angle-180)*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[2] = -(float) Math.sin((angle-180)*Math.PI/180) * length; points[3] = (float) Math.cos((angle-180)*Math.PI/180) * length; }else if(angle <= 360f){ points[0] = (float) Math.cos((angle-270)*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[1] = (float) Math.sin((angle-270)*Math.PI/180) * DEFAULT_POINT_BACK_LENGTH; points[2] = -(float) Math.cos((angle-270)*Math.PI/180) * length; points[3] = -(float) Math.sin((angle-270)*Math.PI/180) * length; } return points;}4、畫指針
//畫指針Paint paintHour = new Paint();paintHour.setAntiAlias(true);paintHour.setStrokeWidth(15);Paint paintMinute = new Paint();paintMinute.setAntiAlias(true);paintMinute.setStrokeWidth(10);Paint paintSecond = new Paint();paintSecond.setAntiAlias(true);paintSecond.setStrokeWidth(5);Calendar now = Calendar.getInstance();float[] hourPoints = calculatePoint(now.get(Calendar.HOUR_OF_DAY)%12/12f*360, hourPointerLength);canvas.drawLine(hourPoints[0], hourPoints[1], hourPoints[2], hourPoints[3], paintHour);float[] minutePoints = calculatePoint(now.get(Calendar.MINUTE)/60f*360, minutePointerLength);canvas.drawLine(minutePoints[0], minutePoints[1], minutePoints[2], minutePoints[3], paintMinute);float[] secondPoints = calculatePoint(now.get(Calendar.SECOND)/60f*360, secondPointerLength);canvas.drawLine(secondPoints[0], secondPoints[1], secondPoints[2], secondPoints[3], paintSecond);
5、畫圓心
//畫圓心Paint paintCenter = new Paint();paintCenter.setColor(Color.WHITE);canvas.drawCircle(0, 0, 2, paintCenter);最后只要啟動一個無限循環的線程，每隔1秒針重繪一下View就能讓指針動起來了private Thread timeThread = new Thread() { @Override public void run() { try { while(true){ updateHandler.sendEmptyMessage(0); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } }};private Handler updateHandler = new Handler() { @Override public void handleMessage(Message msg) { invalidate(); }};以上就是教大家如何利用Android畫個時鐘的詳細步驟代碼，希望對大家的學習Android軟件編程有所幫助。
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