自定义控件实战<三> 动态圆弧控件

上一篇文章实现一个图片和文字混合展示的控件,这篇文章在此基础上面继续实现一个动态的圆弧控件.

一、在attrs.xml中添加自定义属性：

<?xml version="1.0" encoding="utf-8"?> <resources> <attr name="firstColor" format="color" /> <attr name="secondColor" format="color" /> <attr name="circleLength" format="dimension" /> <attr name="circleWidth" format="dimension" /> <attr name="speed" format="integer" /> <declare-styleable name="CustomProgressBar"> <attr name="firstColor" /> <attr name="secondColor" /> <attr name="circleLength" /> <attr name="circleWidth" /> <attr name="speed" /> </declare-styleable> </resources>

二、对应的布局文件：

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:gravity="center_horizontal" tools:context="com.shi.androidstudio.brokenline.MainActivity"> <com.shi.androidstudio.brokenline.SimpleView_03 android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10dp" app:firstColor = "@color/colorAccent" app:secondColor = "@color/colorPrimaryDark" app:speed = "20" app:circleLength = "100dp" app:circleWidth = "20dp" /> </LinearLayout>

三、重写SimpleView_03控件的构造函数：

public SimpleView_03(Context context) { this(context, null); } public SimpleView_03(Context context, AttributeSet attrs) { this(context, attrs, 0); } public SimpleView_03(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); /** * 获得我们所定义的自定义样式属性 */ TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomProgressBar, defStyleAttr, 0); int length = a.getIndexCount(); for (int i = 0; i < length; i++) { int attr = a.getIndex(i); switch (attr) { case R.styleable.CustomProgressBar_firstColor: mFirstColor = a.getColor(attr,Color.BLACK); break; case R.styleable.CustomProgressBar_secondColor: mSecondColor = a.getColor(attr,Color.WHITE); break; case R.styleable.CustomProgressBar_circleLength: mCircleLength = a.getDimension(attr, 50.00f); break; case R.styleable.CustomProgressBar_circleWidth: mCircleWidth = a.getDimension(attr, 20.00f); break; case R.styleable.CustomProgressBar_speed: mSpeed = a.getInt(attr,10); break; } } a.recycle(); new Thread(new Runnable() { @Override public void run() { while (true) { mProgress = mProgress % 360; postInvalidate(); mProgress++; if (mProgress == 360) { isNext = !isNext; } SystemClock.sleep(mSpeed); } } }).start(); }

四、重写SimpleView_03控件的onDraw：

@Override protected void onDraw(Canvas canvas) { Paint mPaint_01 = new Paint(); mPaint_01.setAntiAlias(true); //设置画笔为无锯齿 mPaint_01.setColor(mFirstColor); //设置画笔颜色 canvas.drawColor(Color.WHITE); //白色背景 mPaint_01.setStrokeWidth(mCircleWidth); //线宽 mPaint_01.setStyle(Paint.Style.STROKE); int centerX = getMeasuredWidth()/2; int centerY = getMeasuredHeight()/2; RectF oval = new RectF(); //RectF对象 oval.left = centerX - mCircleLength; //左边 oval.top = centerY - mCircleLength; //上边 oval.right = centerX + mCircleLength; //右边 oval.bottom = centerY + mCircleLength; //下边 Paint mPaint_02 = new Paint(); mPaint_02.setAntiAlias(true); //设置画笔为无锯齿 mPaint_02.setColor(mSecondColor); //设置画笔颜色 canvas.drawColor(Color.WHITE); //白色背景 mPaint_02.setStrokeWidth(mCircleWidth); //线宽 mPaint_02.setStyle(Paint.Style.STROKE); if(!isNext){ canvas.drawCircle(centerX,centerY,mCircleLength,mPaint_01); canvas.drawArc(oval, 0, mProgress, false, mPaint_02); //绘制圆弧 }else{ canvas.drawCircle(centerX,centerY,mCircleLength,mPaint_02); canvas.drawArc(oval, 0, mProgress, false, mPaint_01); //绘制圆弧 } }

这里讲解一下drawCircle和drawArc函数：

drawCircle(float cx, float cy, float radius, Paint paint) 官方解释： Draw the specified circle using the specified paint. 使用指定的画笔绘制一个指定的圆,其中cx,cy为圆的圆心，radius为圆的半径,paint为画笔. drawArc(RectF oval, float startAngle, float sweepAngle, boolean useCenter, Paint paint) 官方解释： Draw the specified arc, which will be scaled to fit inside the specified oval. 使用指定的画笔绘制一个指定圆弧,其中oval为圆弧所在的椭圆对象； 系统默认在当前页面建立一个X轴向右，Y轴向下的坐标系，其中的startAngle为圆弧的起始角度 ,sweepAngle为圆弧的角度，useCenter表示是否显示半径连线，为true则显示圆弧与圆心的半径连线，false不显示 ,paint为画笔.

五、效果图：

附上demo下载