android listview,GridView 和 ScrollView

標籤：android listview   gridview   relativelayout   linearlayout   measure   

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;最外面布局採用 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 依然採用 RelativeLayout  布局，自訂RelativeLayout  並重寫 onMeasure方法

@Overrideprotected 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);    }

android listview,GridView 和 ScrollView