Android自定义view实现圆形waveview

Android自定义view实现圆形waveview

最近学习了贝塞尔曲线的一些知识，刚好项目中需要实现一个圆形进度，然后就将实现的waveView记录一下。需要使用的知识大概有自定义view、贝塞尔曲线、valueAnimator（属性动画）、Xfermode等。
以下为效果图：

废话不多说，直接上代码这里只是一些重要的代码。如果需要demo可以去下载。
下载地址

首先需要自定义view的属性：

<declare-styleable name="custom_wave_view_attr">

    <attr name="circle_color" format="color"></attr>       //圆的颜色
    <attr name="circle_background_color" format="color"></attr>       //圆的背景色
    <attr name="progress_wave_color" format="color"></attr>       //水波纹的颜色
    <attr name="progress_text_size" format="dimension"></attr>   //字体的大小
    <attr name="progress_text_color" format="color"></attr>          //字体的颜色

</declare-styleable>

第二步自定义CustomWaveView

1、实现构造方法，在构造方法中获取属性值

TypedArray ta = context.obtainStyledAttributes(attrs,R.styleable.custom_wave_view_attr);
//圆的颜色
circle_color =        ta.getColor(R.styleable.custom_wave_view_attr_circle_color,getResources().getColor(android.R.color.black));
//圆的背景色
circle_bg_color =   ta.getColor(R.styleable.custom_wave_view_attr_circle_background_color,getResources().getColor(android.R.color.white));
//水波纹颜色
wave_color = ta.getColor(R.styleable.custom_wave_view_attr_progress_wave_color,getResources().getColor(android.R.color.holo_blue_dark));
//字体的颜色
text_color = ta.getColor(R.styleable.custom_wave_view_attr_progress_text_color,getResources().getColor(android.R.color.black));
//字体的大小
textSize = ta.getDimension(R.styleable.custom_wave_view_attr_progress_text_size,30f);
//释放资源
ta.recycle();

2、初始化画笔

//初始化背景圆画笔
mBgCirclePaint = new Paint();
//抗锯齿
mBgCirclePaint.setAntiAlias(true);
//设置背景圆的背景色
mBgCirclePaint.setColor(circle_bg_color);
//设置充满
mBgCirclePaint.setStyle(Paint.Style.FILL);
//初始化水波纹画笔
mWavePaint = new Paint();
//抗锯齿
mWavePaint.setAntiAlias(true);
//设置水波纹的背景色
mWavePaint.setColor(wave_color);
//设置充满
mWavePaint.setStyle(Paint.Style.FILL);
//使用Xfermode获取重叠部分
mWavePaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

3、绘制贝塞尔曲线。以下为原理图。

/**
* 初始化贝塞尔曲线上的点
*/
private void reset() {
    startP = new PointF(-width, height);
    nextP = new PointF(-width/2, height);
    threeP = new PointF(0, height);
    fourP = new PointF(width/2, height);
    endP = new PointF(width, height);
    controllerP1 = new PointF(-width/4, height);
    controllerP2 = new PointF(-width * 3/4, height);
    controllerP3 = new PointF(width/4, height);
    controllerP4 = new PointF(width * 3/4, height);
}

4、在onDraw方法中画贝塞尔曲线和圆

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    //在透明画布上画背景圆
    mCanvas.drawCircle(width/2, height/2, radius, mBgCirclePaint);
    //贝塞尔曲线
    mPath.reset();
    mPath.moveTo(startP.x, startP.y);
    mPath.quadTo(controllerP1.x, controllerP1.y, nextP.x, nextP.y);
    mPath.quadTo(controllerP2.x, controllerP2.y, threeP.x, threeP.y);
    mPath.quadTo(controllerP3.x, controllerP3.y, fourP.x, fourP.y);
    mPath.quadTo(controllerP4.x, controllerP4.y, endP.x, endP.y);
    mPath.lineTo(endP.x, height);
    mPath.lineTo(-width, height);
    //在透明画布上绘制水波纹
    mCanvas.drawPath(mPath,mWavePaint);
    //将画好的圆绘制在画布上
    canvas.drawBitmap(mBitmap, 0, 0, null);
}

5、使用动画让贝塞尔曲线动起来

/**
* 开始动画 让startP的x点坐标在2S时间内循环移动到0点。
*  depth---进度
*  waveRipple----水波纹的振幅
*/
private void startAnimator() {
    animator = ValueAnimator.ofFloat(startP.x, 0);
    animator.setInterpolator(new LinearInterpolator());
    animator.setDuration(2000);
    //重复循环
    animator.setRepeatCount(ValueAnimator.INFINITE);
    animator.addUpdateListener(new       ValueAnimator.AnimatorUpdateListener() {
    @Override
    public void onAnimationUpdate(ValueAnimator animation) {
       startP.x = (Float) animation.getAnimatedValue();
       startP = new PointF(startP.x, height - depth);
       nextP = new PointF(startP.x + width/2, height - depth);
       threeP = new PointF(nextP.x + width/2, height - depth);
       fourP = new PointF(threeP.x + width/2, height - depth);
       endP = new PointF(fourP.x + width/2, height - depth);
       controllerP1 = new PointF(startP.x + width/4, height - depth + waveRipple);
       controllerP2 = new PointF(nextP.x + width/4, height - depth - waveRipple);
       controllerP3 = new PointF(threeP.x + width/4, height - depth + waveRipple);
       controllerP4 = new PointF(fourP.x + width/4, height - depth - waveRipple);
       invalidate();
    }
 });
 animator.start();
}

第三步在XML中使用自定义View

<com.criclewaveview_master.CustomWaveView
        android:id="@+id/custom_circle_wave_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        wave:circle_color = "@color/circle_color"
        android:layout_centerInParent="true"
        wave:circle_background_color = "@color/circle_bg_color"
        wave:progress_wave_color = "@color/colorAccent"
        wave:progress_text_size = "20sp"
        wave:progress_text_color = "@color/circle_color"/>

这样就完成了自定义WaveView