任何一个可以模拟手表样品中解释手表面对这种逻辑的Android

Question

您好我经历模拟watch.In的onDraw方法的样品我碰到这个逻辑

@Override 
    public void onDraw(Canvas canvas, Rect bounds) { 
     mTime.setToNow(); 

     // Draw the background. 
     if (isInAmbientMode()) { 
      canvas.drawColor(Color.BLACK); 
     } else { 
      canvas.drawRect(0, 0, canvas.getWidth(), canvas.getHeight(), mBackgroundPaint); 
     } 

     // Find the center. Ignore the window insets so that, on round watches with a 
     // "chin", the watch face is centered on the entire screen, not just the usable 
     // portion. 
     float centerX = bounds.width()/2f; 
     float centerY = bounds.height()/2f; 

     float secRot = (mTime.second/30f) * (float) Math.PI; 
     int minutes = mTime.minute; 
     float minRot = minutes/30f * (float) Math.PI; 
     float hrRot = ((mTime.hour + (minutes/60f))/6f) * (float) Math.PI; 

     float secLength = centerX - 20; 
     float minLength = centerX - 40; 
     float hrLength = centerX - 80; 

     if (!mAmbient) { 
      float secX = (float) Math.sin(secRot) * secLength; 
      float secY = (float) -Math.cos(secRot) * secLength; 
      canvas.drawLine(centerX, centerY, centerX + secX, centerY + secY, mHandPaint); 
     } 

     float minX = (float) Math.sin(minRot) * minLength; 
     float minY = (float) -Math.cos(minRot) * minLength; 
     canvas.drawLine(centerX, centerY, centerX + minX, centerY + minY, mHandPaint); 

     float hrX = (float) Math.sin(hrRot) * hrLength; 
     float hrY = (float) -Math.cos(hrRot) * hrLength; 
     canvas.drawLine(centerX, centerY, centerX + hrX, centerY + hrY, mHandPaint); 
    } 

我不理解什么是确切的含义这些线

float secRot = (mTime.second/30f) * (float) Math.PI; 
    int minutes = mTime.minute; 
    float minRot = minutes/30f * (float) Math.PI; 
    float hrRot = ((mTime.hour + (minutes/60f))/6f) * (float) Math.PI; 

Answer 1

它似乎是试图计算每个手的旋转角度。它正在独立移动秒针和分针，但也依赖于分钟来移动时针。在“12点30分”的时针将在12点和1点之间。