一、自定義一個漂亮的圓形progressbar

1、先分析圓環的組成，兩個重疊圓環、寬度、個數、間隔、顏色。

    private void drawOval(Canvas canvas) {
        int center = getWidth() / 2;
        int radius = center - mCircleWidth / 2;
        //mCount是圓環共多少塊，mSplitSize是每塊的間隔，itemSize是每塊對應的角度
        float itemSize = (360 * 1.0f - mCount * mSplitSize) / mCount;
        //圓的大小
 

        RectF oval = new RectF(center - radius, center - radius, center + radius, center + radius);
        mPaintFirst.setColor(mFirstColor);
        //畫第一個灰色的圓環
        for (int i = 0; i < mCount ; i++) {
            canvas.drawArc(oval, (i) * (itemSize + mSplitSize) - 90 , itemSize, false, mPaintFirst);
        }
        //採用掃描漸變再選擇-90°
 

        SweepGradient sweepGradient = new SweepGradient(center,center,colorArray,null);
        matrix.setRotate(-90,center,center);
        sweepGradient.setLocalMatrix(matrix);
        mPaintSecond.setShader(sweepGradient);
        mPaintSecond.setShadowLayer(10, 10, 10, Color.RED);
        //畫第二個圓環
        for
 
 (int i = 0; i < mCurrentCount; i++) {
            canvas.drawArc(oval, (i) * (itemSize + mSplitSize) - 90 , itemSize, false, mPaintSecond);
        }
    }

2、畫文字

 private void drawText(Canvas canvas) {
        float textWidth = textPaint.measureText(mCurrentCount*100/mCount+"%");
        int textHeight = (int) Math.ceil(textPaint.getFontMetrics().descent - textPaint.getFontMetrics().ascent+2);
        canvas.drawText(mCurrentCount * 100 / mCount + "%", getWidth() / 2 - textWidth / 2, getHeight() / 2 + textHeight / 4, textPaint);
    }

3、設定滑動增減音量，設定音量監聽

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                downY = (int) event.getY();
                break;
            case MotionEvent.ACTION_UP:
                int upY = (int) event.getY();
                if (downY > upY) {
                    up();
                } else {
                    down();
                }
                break;
        }
        return true;
    }

    private void down() {
        mCurrentCount--;
        if (mCurrentCount < 0) {
            mCurrentCount = 0;
        }
        changeVolume();
    }

    private void up() {
        mCurrentCount++;
        if (mCurrentCount > mCount - spaceCount) {
            mCurrentCount = mCount - spaceCount;
        }
        changeVolume();
    }

    public void setProgress(int progress){
        float f = mCount*1.0f/100;
        mCurrentCount = (int) (f*progress);
        invalidate();
    }

    private void changeVolume() {
        if (listener != null) {
            listener.volumeChange(mCurrentCount);
        }
        postInvalidate();
    }

    public interface OnVolumeChangeListener {
        void volumeChange(int level);
    }

    private OnVolumeChangeListener listener;

    public void setOnVolumeChangeListener(OnVolumeChangeListener listener) {
        this.listener = listener;
    }

二、自定義view音量控制

    mPaint1.setStrokeCap(Paint.Cap.ROUND);//設定圓弧的圓角

   private void drawOval(Canvas canvas, int center, int radius) {
        float itemSize = (360 * 1.0f - mCount * mSplitSize) / mCount;
        //spaceCount為下方預留幾段空白，計算出總共空白的弧度space
        float space = itemSize * spaceCount + mSplitSize * (spaceCount + 1);
        //圓的大小
        RectF oval = new RectF(center - radius, center - radius, center + radius, center + radius);
        mPaint1.setColor(mFirstColor);
        //加space/2為了讓空白居中
        for (int i = 0; i < mCount - spaceCount; i++) {
            canvas.drawArc(oval, (i) * (itemSize + mSplitSize) + 90 + space / 2, itemSize, false, mPaint1);
        }
        mPaint.setColor(mSecondColor);
        for (int i = 0; i < mCurrentCount; i++) {
            canvas.drawArc(oval, (i) * (itemSize + mSplitSize) + 90 + space / 2, itemSize, false, mPaint);
        }
    }