android - Android 中的 ExpandableLists，我想一次只允许扩展一个父列表

Question

我只想一次展开父列表中的一项，目前我的 onCreate 代码如下。 (按我的意愿工作，但是一次只允许一个父打开的方法不起作用)

public void onCreate(Bundle savedInstanceState) {
        try{
             super.onCreate(savedInstanceState);
             setContentView(R.layout.main);

        final SimpleExpandableListAdapter expListAdapter =
            new SimpleExpandableListAdapter(
                        //FOR LEVEL 1 SCREEN
                    this,
                    createGroupList(),              // METHOD TO CREATE PARENTLIST Creating group List.
                    R.layout.group_row,             // REF TO XML FILENAME.         
                    new String[] { "Group Item" },  // STRING ARRAY HOLDING ONE KEY THAT REF'S ALL PARENT LIST ITEMS.
                    new int[] { R.id.row_name },    // REF TO I.D. OF PARENT XML. ID of each group item.-Data under the key goes into this TextView.                    
                    createChildList(),              // METHOD TO CREATE CHILD LST. childData describes second-level entries.
                    R.layout.child_row,             // XMLFILE NAME FOR CHILD LIST.Layout for sub-level entries(second level).
                    new String[] {"Sub Item"},      // KEY FOR CHILD ITEMS IN HASHMAP. Keys in childData maps to display.
                    new int[] { R.id.grp_child}     // XML ID FOR TEXTVIEW. Data under the keys above go into these TextViews.
                );
            setListAdapter( expListAdapter );       // setting the adapter in the list.

        //**THIS IS WHAT I DONT KNOW HOW TO CODE:**


            list = (ExpandableListView) findViewById(R.id.row_name);
            list.setAdapter( expListAdapter);
            list.setGroupIndicator(null);


            list.setOnGroupExpandListener(new OnGroupExpandListener() {

                public void onGroupExpand(int groupPosition) {
                    int len = expListAdapter.getGroupCount();
                    for (int i = 0; i < len; i++) {
                        if (i != groupPosition) {
                            list.collapseGroup(i);
                        }
                    }
                }
            });

        }catch(Exception e){

            System.out.println("Errrr +++ " + e.getMessage());
        }
    }

我理解上面的代码，但是，我不使用 expandableListViews，我将我的程序引用到我的 .xml 文件中，其中包含可扩展列表的布局。所以我不知道如何将以上内容应用到我的程序中......

主.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
 <ExpandableListView android:id="@+id/list"
               android:layout_width="fill_parent" 
               android:layout_height="fill_parent"
               android:background="@drawable/bkg"/>

     <TextView android:id="@+id/android:empty"
               android:layout_width="fill_parent" 
               android:layout_height="fill_parent"
               android:text="No items"/>
</LinearLayout>

不知道怎么申请的方法如下:

                    list = (ExpandableListView) findViewById(R.id.row_name);
            list.setAdapter( expListAdapter);
            list.setGroupIndicator(null);

            list.setOnGroupExpandListener(new OnGroupExpandListener() {
                    public void onGroupExpand(int groupPosition) {
                    int len = expListAdapter.getGroupCount();
                    for (int i = 0; i < len; i++) {
                        if (i != groupPosition) {
                            list.collapseGroup(i);
                        }
                    }
                }
            });

1) 如何将“列表”引用到我的可扩展列表 Activity 中？

列表在类中定义为private ExpandableListView list;

我现在没有任何错误，但该方法不起作用。

非常感谢任何帮助!

Answer 1

// Declare variable 
private static int prev = -1;
// and OnGroupExpandListener implement


 mExpandableList.setOnGroupExpandListener(new OnGroupExpandListener() {

            @Override
            public void onGroupExpand(int groupPosition) {

                if(prev!=-1)
                {

                    mExpandableList.collapseGroup(prev);    

                }
                prev=groupPosition;
            }
        });

---

更新解决方案

mExpandableList.setOnGroupExpandListener(new OnGroupExpandListener() {
    // Keep track of previous expanded parent
    int previousGroup = -1;

    @Override
    public void onGroupExpand(int groupPosition) {
        // Collapse previous parent if expanded.
        if ((previousGroup != -1) && (groupPosition != previousGroup)) {
            mExpandableList.collapseGroup(previousGroup);
        }
        previousGroup = groupPosition;
    }
});