Android控制条 Android自定义控制条效果

时间:2021-04-22 rains at night 人气:0

ControlBar

自定义一个可以调节大小的控件，可以根据宽高来指定控制条方向。当width >= heigth时，为横向控制条，否则为竖向控制条

onMeasure

根据用户给定的width与height计算控制条的坐标。

1.主要的计算思路

先计算横向的的坐标点，竖向的坐标点即横向的逆时针旋转90度再向下移一个heigth的长度。

//横向坐标点
mHorLArcFirstPathX = mRadius + mLArcLength;
mHorLArcFirstPathY = startY + mBarHeight * (1.0f - LITTLE_ARC_PER_WIDTH) / 2.0f ;
//对应竖向坐标点
mLArcFirstPathX = mHorLArcFirstPathY;
mLArcFirstPathY = -mHorLArcFirstPathX + longSide;

onDraw

根据计算所得坐标点，构建路径，绘图

super.onDraw(canvas);
  mBgPaint.setColor(Color.WHITE);
  canvas.drawPath(mBgPath, mBgPaint);
  mBgPaint.setColor(Color.GRAY);
  canvas.drawPath(mMaxPath, mBgPaint);
  canvas.drawPath(mPath, mPaint);
  mBgPaint.setColor(Color.WHITE);
  if(mDirection == HORIZONTAL){
   canvas.drawCircle(mRadius + mPercent * mBarWidth, mRadius, mRadius, mBgPaint);
   canvas.drawCircle(mRadius + mPercent * mBarWidth, mRadius, mRadius - SPACING, mPaint);
  }else {
   canvas.drawCircle(mRadius, mHeight - (mRadius + mPercent * mBarWidth), mRadius, mBgPaint);
   canvas.drawCircle(mRadius, mHeight - (mRadius + mPercent * mBarWidth), mRadius - SPACING, mPaint);
  }

onTouchEvent

根据手指滑动，动态调整数值大小

@Override
 public boolean onTouchEvent(MotionEvent event) {
  switch (event.getAction()){
   case MotionEvent.ACTION_DOWN:
   case MotionEvent.ACTION_MOVE:
    float distance = 0;
    float maxDist = 0;
    switch (mDirection){
     case HORIZONTAL:
      distance = event.getX();
      maxDist = mWidth;
      break;
     case VERTICAL:
      distance = mHeight - event.getY();
      maxDist = mHeight;
      break;
    }
    if(distance <= mRadius){
     updateView(MIN_VALUE);
    }else if(distance >= maxDist - mRadius){
     updateView(MAX_VALUE);
    }else {
     updateView(calculatingValue(distance));
    }
    return true;
   default:
    return super.onTouchEvent(event);
  }
 }

实际效果如图所示

横向控制条

竖向控制条

项目github地址

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