y23462001的部落格

• View的Life Cycle主要經過onMeasureàonLayoutàonDraw三個步驟
• View的進行過程是遞迴的概念，最先處理的是View中最小的地方，由下圖範例，執行順序為CàBàA

• onMeasure主要是測量在Layout中此view的大小
• onLayout負責將View放在Layout對應的位置中
• 當程式執行addView將某個View加進Layout時，會在呼叫requestLayout

public void addView(View child, int index, LayoutParams params) {
      // addViewInner() will call child.requestLayout() when setting the new LayoutParams
      // therefore, we call requestLayout() on ourselves before, so that the child's
      // request will be blocked at our level
      requestLayout();
      addViewInner(child, index, params, false);
}

• requestLayout就會執行onMeasure和onLayout