如何在 Android 中保存和恢复 ExpandableListView 的状态? [英] How to save and restore the state of an ExpandableListView in Android?

问题描述

是否可以在 Android 中保存和恢复 ExpandableListView 的状态(哪些项目已折叠，哪些未折叠)?

Is it possible to save and restore the state (which items are collapsed and which not) of an ExpandableListView in Android?

如果可能，我该怎么做?

If it is possible, how can I do that?

我可以在 onPause()/onResume() 中访问 ExpandableListView 吗?如何访问?

Can I access the ExpandableListView in onPause() / onResume() and how?

推荐答案

我遍历组并保存所有组的状态:

I iterate through the groups and save the state of them all:

int numberOfGroups = MyExpandableListViewAdapter.getGroupCount();
boolean[] groupExpandedArray = new boolean[numberOfGroups];
  for (int i=0;i<numberOfGroups;i++)
    groupExpandedArray[i] = MyExpandableListView.isGroupExpanded(i);

然后为恢复状态:

for (int i=0;i<groupExpandedArray.length;i++)
  if (groupExpandedArray[i] == true)
    MyExpandableListView.expandGroup(i);

我不明白如何在 onPause()/onResume() 中访问 ListView 是什么意思，如果你将 ListView 对象存储为活动类的成员，它应该可以从那里访问.

I don't understand what you mean by how to access the ListView in onPause() / onResume(), it should be accessible from there if you store the ListView object as a member of the activity class.

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