android listview,GridView 和 ScrollView

前段時間 遇到 listview 和scrollview 布局的問題 ，現在提供一個解決方案

if (listAdapter == null || listAdapter.getCount() == 0) {
  return;
}
int totalHeight = 0;
for (int i = 0; i < listAdapter.getCount(); i++) {
  View listItem = listAdapter.getView(i, null, listView);
  listItem.measure(0, 0);
  totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
listView.setLayoutParams(params);
listView.clearFocus();

這個裡面有一個很重要的問題，在調用 listItem.measure(0, 0); 有些時候會報錯，根本原因在於 listitem 的布局;最外面布局采用 LinearLayout,在調用listItem.measure(0, 0)時，其實根本是調用 LinearLayout.measure 方法；同樣 RelativeLayout 布局也是一樣，但是，調用RelativeLayout .measure 方法 會報錯 。

解決辦法：

1.listitem 布局最外層 用LinearLayout。

2. listitem 布局最外層 依然采用 RelativeLayout 布局，自定義RelativeLayout 並重寫 onMeasure方法

 

@Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec){

    int widthSize = MeasureSpec.getSize(widthMeasureSpec);      
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);

    // Restrict the aspect ratio to 1:1, fitting within original specified dimensions
    int chosenDimension = Math.min(widthSize, heightSize);
    widthMeasureSpec = MeasureSpec.makeMeasureSpec(chosenDimension, MeasureSpec.AT_MOST);
    heightMeasureSpec = MeasureSpec.makeMeasureSpec(chosenDimension, MeasureSpec.AT_MOST);

    getLayoutParams().height = chosenDimension;
    getLayoutParams().width = chosenDimension;
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);    
}