Question

能否保存并恢复Android 扩展式List View的状态(哪些物品已经倒塌,哪些没有倒塌)?

如果可能的话,我该怎么做呢?

我能访问Pause()/Resume()的扩展式List View吗? 如何访问?

Answer 1

透过各团体,拯救各团体,

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

然后恢复国家:

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

我不明白你的意思是,如何访问Pause()/Resume()中的ListView,如果将 ListView 对象作为活动类的成员存储,那么从那里应该可以访问。

Answer 2

改善Floaf的回答:宣布

 public static int firstVisiblePosition=0;

暂停暂停

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

续续续

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

这将不仅恢复每个组的状态, 还会滚动到活动暂停时所看到的“ 儿童视图 ” 。

Answer 3

更简单的方法可能是, 如果你再使用 SetOn GroupClickListner 和 setOnChildClickLickLister 只保留最后选择的儿童视野和组合Positin整数, 然后再检查它并做出正确回应,

if (childPosition > 0) {
    mExpandableList.expandGroup(groupPositin);
}
mExpandableList.setItemChecked(groupPositin + childPosition , true);

您只需在 SetOn GroupListener 方法中记住将儿童位置设为 0 。

Answer 4

我遇到同样的问题,找到了更好的答案。我有一个碎片,用“强势”的“强力”的“拯救Instance State

我在这里保存列表状态

@Override
public void onSaveInstanceState( @NonNull Bundle outState )
{
    super.onSaveInstanceState( outState );

    ExpandableListView expandable = getView() != null ? getView().findViewById( R.id.expandable ) : null;
    if( expandable != null )
    {
        int groupsCount = expandable.getExpandableListAdapter()
                                    .getGroupCount();
        boolean[] groupExpandedArray = new boolean[groupsCount];
        for( int i = 0; i < groupsCount; i += 1 )
        {
            groupExpandedArray[i] = expandable.isGroupExpanded( i );
        }
        outState.putBooleanArray( "groupExpandedArray", groupExpandedArray );
        outState.putInt( "firstVisiblePosition", expandable.getFirstVisiblePosition() );
    }
}

在这里,我恢复它当需要它的时候

@Override
public void onViewStateRestored( @Nullable Bundle savedInstanceState )
{
    super.onViewStateRestored( savedInstanceState );
    if( savedInstanceState != null )
    {
        boolean[]          groupExpandedArray   = savedInstanceState.getBooleanArray( "groupExpandedArray" );
        int                firstVisiblePosition = savedInstanceState.getInt( "firstVisiblePosition", -1 );
        ExpandableListView expandable           = getView() instanceof ViewGroup ? getView().findViewById( R.id.expandable ) : null;
        if( expandable != null && groupExpandedArray != null )
        {
            for( int i = 0; i < groupExpandedArray.length; i++ )
            {
                if( groupExpandedArray[i] )
                    expandable.expandGroup( i );
            }
            if( firstVisiblePosition >= 0 )
                expandable.setSelection( firstVisiblePosition );
        }
    }
}

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