Android实现光点模糊渐变的自旋转圆环特效

/** * Created by jiangzn on 17/2/3. */public class RoundLightBarView extends ImageView {  private int mTotalWidth, mTotalHeight;  private int mCenterX, mCenterY;  //底色画笔  private Paint mCirclePaint;  //进度条画笔  private Paint mProgressPaint;  //圆点画笔  private Paint mbitmapPaint;  private Matrix mMatrix; // 矩阵,用于对图片进行一些操作  private float[] pos;   // 当前点的实际位置  private float[] tan;   // 当前点的tangent值,用于计算图片所需旋转的角度    private int mCircleR;    private Context mContext;  //距离外围的边距  private float interval ;   private int startAngle = 1;   //球  private Bitmap mLititleBitmap; // 圆点图片   public RoundLightBarView(Context context, AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);   }   public RoundLightBarView(Context context, AttributeSet attrs) {    super(context, attrs);    mContext = context;    interval = DensityUtils.px2dip(mContext, 50);    //初始化画笔    initPaint();    //初始化bitmap    initBitmap();  }   private void initBitmap() {    mMatrix=new Matrix();    pos = new float[2];    tan = new float[2];    mLititleBitmap= ((BitmapDrawable) getResources()        .getDrawable(R.mipmap.white_round))        .getBitmap();  }   private void initPaint() {    //画黑底的深色圆画笔    mCirclePaint = new Paint();    //抗锯齿    mCirclePaint.setAntiAlias(true);    // 防抖动    mCirclePaint.setDither(true);    // 开启图像过滤，对位图进行滤波处理。    mCirclePaint.setFilterBitmap(true);    mCirclePaint.setColor(Color.BLACK);    //空心圆    mCirclePaint.setStyle(Paint.Style.STROKE);    //圆半径    mCircleR = DensityUtils.px2dip(mContext, 20);    mCirclePaint.setStrokeWidth(mCircleR);     //画彩色圆弧的画笔    mProgressPaint = new Paint();    //抗锯齿    mProgressPaint.setAntiAlias(true);    // 防抖动    mProgressPaint.setDither(true);    // 开启图像过滤，对位图进行滤波处理。    mProgressPaint.setFilterBitmap(true);    mProgressPaint.setColor(Color.BLUE);    //空心圆    mProgressPaint.setStyle(Paint.Style.STROKE);    //设置笔刷样式为原型    mProgressPaint.setStrokeCap(Paint.Cap.ROUND);    //设置圆弧粗    mProgressPaint.setStrokeWidth(mCircleR);    //将绘制的内容显示在第一次绘制内容之上    mProgressPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));      //圆点画笔    mbitmapPaint = new Paint();    mbitmapPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));    mbitmapPaint.setStyle(Paint.Style.FILL);    mbitmapPaint.setAntiAlias(true);   }   @Override  protected void onDraw(Canvas canvas) {    super.onDraw(canvas);    //canvas去锯齿    canvas.setDrawFilter(        new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG));    //画底色圆    canvas.drawCircle(mCenterX, mCenterY, mCenterX - mCircleR - interval, mCirclePaint);    //画进度条    int colorSweep[] = {Color.TRANSPARENT, Color.parseColor("#3bbaea"),Color.parseColor("#7ac9d3"),Color.parseColor("#7cc9d0")};     //设置渐变色    sweepGradient = new SweepGradient(mCenterX, mCenterY, colorSweep, null);    //按照圆心旋转    Matrix matrix = new Matrix();    matrix.setRotate(startAngle, mCenterX, mCenterY);    sweepGradient.setLocalMatrix(matrix);     mProgressPaint.setShader(sweepGradient);     canvas.drawArc(        new RectF(0 + mCircleR + interval, 0 + mCircleR + interval,            mTotalWidth - mCircleR - interval, mTotalHeight - mCircleR - interval),        2 + startAngle, 350, false, mProgressPaint);     startAngle++;    if (startAngle == 360) {      startAngle = 1;    }     //绘制白色小星星    Path orbit = new Path();    //通过Path类画一个90度（180—270）的内切圆弧路径    orbit.addArc(        new RectF(0 + mCircleR + interval, 0 + mCircleR + interval,            mTotalWidth - mCircleR - interval, mTotalHeight - mCircleR - interval)        , 2 + startAngle, 350);    // 创建 PathMeasure    PathMeasure measure = new PathMeasure(orbit, false);    measure.getPosTan(measure.getLength() * 1, pos, tan);    mMatrix.reset();    mMatrix.postScale(2,2);    mMatrix.postTranslate(pos[0] - mLititleBitmap.getWidth() , pos[1] - mLititleBitmap.getHeight() );  // 将图片绘制中心调整到与当前点重合    canvas.drawBitmap(mLititleBitmap, mMatrix, mbitmapPaint);//绘制球    mbitmapPaint.setColor(Color.WHITE);    //绘制实心小圆圈    canvas.drawCircle(pos[0], pos[1], 5, mbitmapPaint);     //启动绘制    postInvalidateDelayed(10);  }   SweepGradient sweepGradient;   @Override  protected void onSizeChanged(int w, int h, int oldw, int oldh) {    super.onSizeChanged(w, h, oldw, oldh);    mTotalWidth = w;    mTotalHeight = h;    mCenterX = mTotalWidth / 2;    mCenterY = mTotalHeight / 2;    } }

 // 创建 PathMeasure    PathMeasure measure = new PathMeasure(orbit, false);    measure.getPosTan(measure.getLength() * 1, pos, tan);    mMatrix.reset();    mMatrix.postScale(2,2);    mMatrix.postTranslate(pos[0] - mLititleBitmap.getWidth() , pos[1] - mLititleBitmap.getHeight() );  // 将图片绘制中心调整到与当前点重合    canvas.drawBitmap(mLititleBitmap, mMatrix, mbitmapPaint);//绘制球    mbitmapPaint.setColor(Color.WHITE);    //绘制实心小圆圈    canvas.drawCircle(pos[0], pos[1], 5, mbitmapPaint);