任何一個可以模擬手錶樣品中解釋手錶面對這種邏輯的Android

Question

您好我經歷模擬watch.In的onDraw方法的樣品我碰到這個邏輯

@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); 
    } 

我不理解什麼是確切的含義這些線

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

它似乎是試圖計算每個手的旋轉角度。它正在獨立移動秒針和分針，但也依賴於分鐘來移動時針。在「12點30分」的時針將在12點和1點之間。