Android自定義View制作儀表盤界面

前言

最近我跟自定義View槓上了，甚至說有點上瘾到走火入魔了。身為菜鳥的我自然要查閱大量的資料，學習大神們的代碼，這不，前兩天正好在郭神在微信公眾號裡推送一片自定義控件的文章——一步步實現精美的鐘表界面。正適合我這種菜鳥來學習，閒著沒事，我就差不多依葫蘆畫瓢也寫了一個自定義表盤View，現在純粹最為筆記記錄下來。先展示下效果圖：

下面進入正題

自定義表盤屬性

老規矩，先在attrs文件裡添加表盤自定義屬性

<declare-styleable name="WatchView"> 
<attr name="watchRadius" format="dimension"/> //表盤半徑 
<attr name="watchPadding" format="dimension"/> //表盤相對控件邊框距離 
<attr name="watchScalePadding" format="dimension"/> //刻度相對表盤距離 
<attr name="watchScaleColor" format="color|reference"/> //常規刻度顏色 
<attr name="watchScaleLength" format="dimension|reference"/> //常規刻度長度 
<attr name="watchHourScaleColor" format="dimension|reference"/> //整點刻度顏色 
<attr name="watchHourScaleLength" format="dimension|reference"/> //整點刻度長度 
<attr name="hourPointColor" format="color|reference"/> //時針顏色 
<attr name="hourPointLength" format="dimension|reference"/> //時針長度 
<attr name="minutePointColor" format="color|reference"/> //分針顏色 
<attr name="minutePointLength" format="dimension|reference"/> //分針長度 
<attr name="secondPointColor" format="color|reference"/> //秒針顏色 
<attr name="secondPointLength" format="dimension|reference"/> //秒針長度 
<attr name="timeTextSize" format="dimension|reference"/> //表盤字體大小 
<attr name="timeTextColor" format="color|reference"/> //表盤字體顏色 
</declare-styleable>

在自定義View的構造方法種獲取自定義屬性

先將屬性變量聲明如下：

<span > /**表盤邊距*/ 
private float mWatchPadding = 5; 
/**表盤與刻度邊距*/ 
private float mWatchScalePadding = 5; 
/**表盤半徑*/ 
private float mWatchRadius = 250; 
/**表盤刻度長度*/ 
private float mWatchScaleLength; 
/**表盤刻度顏色*/ 
private int mWatchScaleColor = Color.BLACK; 
/**表盤整點刻度長度*/ 
private float mHourScaleLength = 8; 
/**表盤整點刻度顏色*/ 
private int mHourScaleColor = Color.BLUE; 
/**表盤時針顏色*/ 
private int mHourPointColor = Color.BLACK; 
/**表盤時針長度*/ 
private float mHourPointLength = 100; 
/**表盤分針顏色*/ 
private int mMinutePointColor = Color.BLACK; 
/**表盤分針長度*/ 
private float mMinutePointLength = 130; 
/**表盤秒針顏色*/ 
private int mSecondPointColor = Color.RED; 
/**表盤秒針長度*/ 
private float mSecondPointLength = 160; 
/**表盤尾部指針長度*/ 
private float mEndPointLength; 
/**表盤數字顏色*/ 
private int mTimeTextColor = Color.BLACK; 
/**表盤數字大小*/ 
private int mTimeTextSize = 15;</span>

在構造方法種獲取自定義屬性

<span > public WatchView(Context context, AttributeSet attrs) { 
super(context, attrs); 
TypedArray array = context.obtainStyledAttributes(attrs,R.styleable.WatchView); 
int n = array.getIndexCount(); 
for (int i = 0;i<n;i++){ 
int attr = array.getIndex(i); 
switch (attr){ 
case R.styleable.WatchView_watchRadius: 
mWatchRadius = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,60)); 
break; 
case R.styleable.WatchView_watchPadding: 
mWatchPadding = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,5)); 
break; 
case R.styleable.WatchView_watchScalePadding: 
mWatchScalePadding = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,3)); 
break; 
case R.styleable.WatchView_watchScaleLength: 
mWatchScaleLength = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,5)); 
break; 
case R.styleable.WatchView_watchScaleColor: 
mWatchScaleColor = array.getColor(attr, Color.parseColor("#50000000")); 
break; 
case R.styleable.WatchView_watchHourScaleLength: 
mHourScaleLength = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,10)); 
break; 
case R.styleable.WatchView_watchHourScaleColor: 
mHourScaleColor = array.getColor(attr,Color.BLACK); 
break; 
case R.styleable.WatchView_hourPointLength: 
mHourPointLength = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,35)); 
break; 
case R.styleable.WatchView_hourPointColor: 
mHourPointColor = array.getColor(attr,Color.BLACK); 
break; 
case R.styleable.WatchView_minutePointLength: 
mMinutePointLength = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,40)); 
break; 
case R.styleable.WatchView_minutePointColor: 
mMinutePointColor = array.getColor(attr,Color.BLACK); 
break; 
case R.styleable.WatchView_secondPointLength: 
mSecondPointLength = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,50)); 
break; 
case R.styleable.WatchView_secondPointColor: 
mSecondPointColor = array.getColor(attr,Color.BLUE); 
break; 
case R.styleable.WatchView_timeTextSize: 
mTimeTextSize = array.getDimensionPixelSize(attr,MyUtil.dip2px(context,15)); 
break; 
case R.styleable.WatchView_timeTextColor: 
mTimeTextColor = array.getColor(attr,Color.BLACK); 
break; 
} 
} 
array.recycle(); 
}</span>

設置控件大小

這裡當然就是重寫onMeasure方法啦，這裡我們處理的簡單點，如下面代碼所示，當我們將控件的寬高都設定為wrap_content（即MeasureSpec.UNSPECIFED）時，我們將寬高設定為默認值（wrapContentSize）和圓盤半徑+圓盤邊距（mWatchRadius+mWatchPadding）之間取最大值，其他情況下就取系統自取值。當然作為一個嚴謹的控件，僅僅這樣處理肯定是不行的。項目中，我們要根據我們的需求自行修改裡面的代碼以適配。

<span > @Override 
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
int wrapContentSize = 1000; 
int widthSize = MeasureSpec.getSize(widthMeasureSpec); 
int widthMode = MeasureSpec.getMode(widthMeasureSpec); 
int heightSize = MeasureSpec.getSize(heightMeasureSpec); 
int heightMode = MeasureSpec.getMode(heightMeasureSpec); 
if (widthMode == MeasureSpec.UNSPECIFIED && heightMode == MeasureSpec.UNSPECIFIED){ 
wrapContentSize = (int) Math.max(wrapContentSize,mWatchRadius+mWatchPadding); 
setMeasuredDimension(wrapContentSize,wrapContentSize); 
}else { 
setMeasuredDimension(widthSize,heightSize); 
} 
}</span>

重寫onDraw方法

來到最關鍵真正畫表盤時刻了。一步一步來，首先初始化我們的畫筆（我的習慣，寫一個initPaint方法）

<span > private void initPaint(){ 
mPaint = new Paint(); 
mPaint.setAntiAlias(true); 
mPaint.setColor(Color.WHITE); 
mPaint.setStyle(Paint.Style.FILL); 
}</span>

為了不顯贅述，方便理解，我直接展示代碼，在代碼中解釋

開畫之前我們先將畫筆移動到控件中心點位置，如下：

<span >@Override 
protected void onDraw(Canvas canvas) { 
canvas.translate(getWidth()/2,getHeight()/2); 
}</span>

第一步，畫表盤

<span > /** 
* 畫表盤 
* @param canvas 
*/ 
private void paintWatchBoard(Canvas canvas){ 
initPaint(); 
canvas.save(); 
canvas.drawCircle(0,0,mWatchRadius,mPaint); //畫圓盤 
canvas.restore(); 
}</span>

注：每次畫圖之前都要先調用canvas.save()方法，保存畫筆屬性，畫完之後要調用canvas.restore()方法，重置畫筆屬性

這裡就不一一展示每次畫完之後的效果圖了。

第二步，畫刻度+整點時間數字（刻度從12點方向開始畫）

<span > /** 
* 畫刻度及整點數字 
* @param canvas 
*/ 
private void paintScale(Canvas canvas){ 
int lineLength; //刻度線長度 
canvas.save(); 
for (int i = 0;i<60;i++){ 
if (i%5 == 0){//整點刻度下畫筆相關屬性 
mPaint.setStrokeWidth(MyUtil.dip2px(getContext(),1.5f)); 
mPaint.setColor(mHourScaleColor); 
lineLength = MyUtil.dip2px(getContext(),8); 
canvas.drawLine(0,-mWatchRadius+mWatchScalePadding,0,-mWatchRadius+mWatchScalePadding+lineLength,mPaint); 
mPaint.setColor(mTimeTextColor); 
mPaint.setTextSize(mTimeTextSize); 
canvas.drawText(mTimes[i/5],-mTimeTextSize/2,-mWatchRadius+mWatchScalePadding + lineLength+mTimeTextSize,mPaint);//整點的位置標上整點時間數字 
}else {//非整點刻度下畫筆相關屬性 
mPaint.setStrokeWidth(MyUtil.dip2px(getContext(),0.8f)); 
mPaint.setColor(mWatchScaleColor); 
lineLength = MyUtil.dip2px(getContext(),5); 
canvas.drawLine(0,-mWatchRadius+mWatchScalePadding,0,-mWatchRadius+mWatchScalePadding+lineLength,mPaint); 
} 
canvas.rotate(6);//每次畫完一個刻度線，畫筆順時針旋轉6度（360/60，相鄰兩刻度之間的角度差為6度） 
} 
canvas.restore(); 
}</span>

其中，整點數字我用了羅馬數字來表示

<span >private String[] mTimes = {"XII","Ⅰ","Ⅱ","Ⅲ","Ⅳ","Ⅴ","Ⅵ","Ⅶ","Ⅷ","Ⅸ","Ⅹ","XI"};</span>

 第三步，畫時針、分針、秒針以及其它修飾圖

考慮到時針、分針和秒針大小長度各不一樣，我這裡特意定義了三支畫筆來分別畫時針、分針和秒針。

同樣的，先初始化指針畫筆：

<span >/** 
* 初始化指針 
*/ 
private void initPointPaint(){ 
mHourPaint = new Paint(); 
mHourPaint.setAntiAlias(true); 
mHourPaint.setStyle(Paint.Style.FILL); 
mHourPaint.setStrokeWidth(16); 
mHourPaint.setColor(mHourPointColor); 
mMinutePaint = new Paint(); 
mMinutePaint.set(mHourPaint); 
mMinutePaint.setStrokeWidth(12); 
mMinutePaint.setColor(mMinutePointColor); 
mSecondPaint = new Paint(); 
mSecondPaint.set(mHourPaint); 
mSecondPaint.setStrokeWidth(7); 
mSecondPaint.setColor(mSecondPointColor); 
mEndPointLength = mWatchRadius/6; //（修飾部分）指針尾部長度，定義為表盤半徑的六分之一 
}</span> 

畫指針

<span >/** 
* 畫指針 
* @param canvas 
*/ 
private void paintPoint(Canvas canvas){ 
initPointPaint(); 
Calendar c = Calendar.getInstance(); //取當前時間 
int hour = c.get(Calendar.HOUR_OF_DAY); 
int minute = c.get(Calendar.MINUTE); 
int second = c.get(Calendar.SECOND); 
//繪制時針 
canvas.save(); 
canvas.rotate(hour*30); 
canvas.drawLine(0,0,0,-mHourPointLength,mHourPaint); 
canvas.drawLine(0,0,0,mEndPointLength,mHourPaint); 
canvas.restore(); 
//繪制分針 
canvas.save(); 
canvas.rotate(minute*6); 
canvas.drawLine(0,0,0,-mMinutePointLength,mMinutePaint); 
canvas.drawLine(0,0,0,mEndPointLength,mMinutePaint); 
canvas.restore(); 
//繪制秒針 
canvas.save(); 
canvas.rotate(second*6); 
canvas.drawLine(0,0,0,-mSecondPointLength,mSecondPaint); 
canvas.drawLine(0,0,0,mEndPointLength,mSecondPaint); 
canvas.restore(); 
}</span>

OK，該有的差不多都有了，直接在onDraw中調用吧

<span >@Override 
protected void onDraw(Canvas canvas) { 
canvas.translate(getWidth()/2,getHeight()/2); 
paintWatchBoard(canvas); //畫表盤 
paintScale(canvas); //畫刻度 
paintPoint(canvas); //畫指針 
canvas.drawCircle(0,0,15,mSecondPaint); //為了美觀，也讓表盤更接近我們顯示生活中的樣子，我在圓盤中心畫了一個大紅圓點裝飾秒針 
postInvalidateDelayed(1000); //每隔一秒鐘畫一次 
}</span>

(⊙v⊙)嗯，自定義View大功告成，我們在布局文件裡調用看下效果吧

<span ><?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:zhusp="http://schemas.android.com/apk/res-auto" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:background="@color/colorAccent"> 
<com.wondertek.propertyanimatordemo.WatchView 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
zhusp:timeTextSize="20dp" 
zhusp:watchRadius="150dp" 
zhusp:hourPointLength="80dp" 
zhusp:minutePointLength="100dp" 
zhusp:secondPointLength="115dp"/> 
</RelativeLayout></span>

最後我這裡的靜態效果是這樣的：