Android中的ExpandableLists，我想一次只允许一个父列表扩展

Question

我想一次只扩展父列表中的一个项目，我的onCreate代码目前如下。 （它可以按我的意愿工作，但是一次只打开一个父节点的方法不起作用）

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，我使用expandablelist的布局将我的程序保存到我的.xml文件中。所以我不知道如何将上述内容应用到我的程序中......

main.xml中

<?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>

我不知道如何申请的方法如下：

                    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'list'引用到我的expandablelist活动？

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;
            }
        });

---

使用更新的解决方案进行更新

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;
    }
});

Answer 2

最简单的方法

您可以实施ExpandableListView.OnGroupExpandListener，在所有列表组中运行collapseGroup()，除了单击的列表组。这将做你想要的。

 expandableList.setOnGroupExpandListener(new OnGroupExpandListener() {
        int previousGroup = -1;

        @Override
        public void onGroupExpand(int groupPosition) {
            if(groupPosition != previousGroup)
                expandableList.collapseGroup(previousGroup);
            previousGroup = groupPosition;
        }
    });

Answer 3

我相信直接的解决方案是实现一个适配器来处理您感兴趣的任何事件。

public class MyExpandableListAdapter extends SimpleExpandableListAdapter {

  public Activity mActivity;

  public MyExpandableListAdapter([ARGS USED IN QUESTION], Activity activity) {super([ARGS USED IN QUESTIONS]); mActivity = activity; }

  // then just override the method
  public void onGroupExpanded(int groupPosition) {
    int len = super.getGroupCount();
    ExpandableListView list = (ExpandableListView) mActivity.findViewById(R.id.list);
    for (int i = 0; i < len; i++) {
        if (i != groupPosition) {
            list.collapseGroup(i);
        }
    }
  }
}

通过将列表适配器分离到另一个类中，您不会使用一次性侦听器实现来混乱活动代码。相反，在每个Activity中只需实例化适配器并将其设置在列表

上

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

    // No try catch needed
    MyExpandableListAdapter mAdapter = new MyExpandableListAdapter([ARGS SHOWN IN QUESTION], MainActivity.this);

    ExpandableListView epView = (ExpandableListView) findViewById(R.id.list);
    epView.setAdapter(mAdapter);

    return true;
}

Answer 4

通过创建名为list的公共explist变量，然后通过以下调用将其引用到视图中的适配器，解决了该问题。

list = getExpandableListView(); 

之前的扩展方法因此崩溃了应用程序。在引用list.collapsegroup后，它工作正常。

public void onGroupExpand(int groupPosition) { 
                    System.out.println("GROUP LISTENER WORKS?");
                    if(adptr=="expListAdapter"){
                        int len = expListAdapter.getGroupCount();
                        //System.out.println(len);
                        for (int i = 0; i < len; i++) {
                            if (i != groupPosition) {
                            list.collapseGroup(i);
                            }
                        }

                    }
                    else if(adptr=="expListAdapter2"){
                        int len = expListAdapter2.getGroupCount();
                        for (int i = 0; i < len; i++) {
                            if (i != groupPosition) {
                            list.collapseGroup(i);
                            }
                        }
                        //System.out.println(len);
                    }
                    else if(adptr=="expListAdapter3"){
                        int len = expListAdapter3.getGroupCount();
                        for (int i = 0; i < len; i++) {
                            if (i != groupPosition) {
                            list.collapseGroup(i);
                            }
                        }

                    }
            }

Answer 5

Iram Bukhari的答案很好。但我曾经做过一次改变：

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


 mExpandableList.setOnGroupExpandListener(new OnGroupExpandListener() {

            @Override
            public void onGroupExpand(int groupPosition) {

                if(prev!=-1 && prev!=groupPosition )
                {

                    mExpandableList.collapseGroup(prev);    

                }
                prev=groupPosition;
            }
        });

我添加了prev！= groupPosition作为额外条件。因为如果

item 1 has clicked(opened) 
item 1 has clicked(closed) 
item 1 has clicked(Not opening. because prev has same position so the item is opened and collapsed immediatly ) 

添加条件后

item 1 has clicked(opened) 
item 1 has clicked(closed) 
item 1 has clicked(opened) 

Answer 6

    @Override
    public void onGroupExpanded(int groupPosition) {
        super.onGroupExpanded(groupPosition);
        int len = getGroupCount();

        for (int i = 0; i < len; i++) {
            if (i != groupPosition) {
               expListView.collapseGroup(i);
            }
        }
    }

Answer 7

修改了Iram的答案： 所以你可以重新打开同一个组

// Listview Group expanded listener
    expListView.setOnGroupExpandListener(new OnGroupExpandListener() {

        @Override
        public void onGroupExpand(int groupPosition) {
            if (prevouriousExpandedGroupNumber != -1 && prevouriousExpandedGroupNumber != groupPosition) {
                expListView.collapseGroup(prevouriousExpandedGroupNumber);
            }
            prevouriousExpandedGroupNumber = groupPosition;
        }
    });

Answer 8

正在查看屏幕截图

package com.keshav.myexpandablelistviewexampleworkinginactivity;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class MainActivity extends Activity {

    ExpandableListAdapter listAdapter;
    ExpandableListView expListView;
    List<String> listDataHeader;
    HashMap<String, List<String>> listDataChild;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // tODO get the listview
        expListView = (ExpandableListView) findViewById(R.id.lvExp);

        // TODO preparing list data
        prepareListData();

        listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);

        // setting list adapter
        expListView.setAdapter(listAdapter);

        // Listview Group click listener
        expListView.setOnGroupClickListener(new OnGroupClickListener() {

            @Override
            public boolean onGroupClick(ExpandableListView parent, View v,
                                        int groupPosition, long id) {
                Toast.makeText(getApplicationContext(),
                        "Group Clicked " + listDataHeader.get(groupPosition),
                        Toast.LENGTH_SHORT).show();
                return false;
            }

        });

        // Listview Group expanded listener
        expListView.setOnGroupExpandListener(new OnGroupExpandListener() {

            // TODO Colapse Here Using this... in android
            int previousGroup = -1;
            boolean flag = false;

            @Override
            public void onGroupExpand(int groupPosition) {

                Log.e("keshav", "onGroupClick is -> " + groupPosition);

                Toast.makeText(getApplicationContext(),
                        listDataHeader.get(groupPosition) + " Expanded",
                        Toast.LENGTH_SHORT).show();

                if (groupPosition != previousGroup && flag) {
                    expListView.collapseGroup(previousGroup);
                }
                previousGroup = groupPosition;

                flag = true;

            }
        });


        // Listview Group collasped listener
        expListView.setOnGroupCollapseListener(new OnGroupCollapseListener() {

            @Override
            public void onGroupCollapse(int groupPosition) {
                Toast.makeText(getApplicationContext(),
                        listDataHeader.get(groupPosition) + " Collapsed",
                        Toast.LENGTH_SHORT).show();

            }
        });


        // Todo Listview on child click listener
        expListView.setOnChildClickListener(new OnChildClickListener() {

            @Override
            public boolean onChildClick(ExpandableListView parent, View v,
                                        int groupPosition, int childPosition, long id) {
                // TODO Auto-generated method stub
                Toast.makeText(
                        getApplicationContext(),
                        listDataHeader.get(groupPosition)
                                + " : "
                                + listDataChild.get(
                                listDataHeader.get(groupPosition)).get(
                                childPosition), Toast.LENGTH_SHORT)
                        .show();
                return false;
            }
        });
    }

    /*
     * Preparing the list data
     */
    private void prepareListData() {
        listDataHeader = new ArrayList<String>();
        listDataChild = new HashMap<String, List<String>>();

        // Adding child data
        listDataHeader.add("Months");
        listDataHeader.add("Top 250");
        listDataHeader.add("Now Showing");
        listDataHeader.add("Coming Soon..");


        // Adding child data
        List<String> weeks = new ArrayList<String>();
        weeks.add("Sunday");
        weeks.add("Monday");
        weeks.add("Tuesday");
        weeks.add("Wednesday");
        weeks.add("Thursday");
        weeks.add("Friday");
        weeks.add("Saturday");


        // Adding child data
        List<String> top250 = new ArrayList<String>();
        top250.add("Om Shanti Om");
        top250.add("Badshah");
        top250.add("Bahubali Part 1");
        top250.add("Carry on Jatta");
        top250.add("Sholey");
        top250.add("Mard");
        top250.add("Dewwar");


        List<String> nowShowing = new ArrayList<String>();
        nowShowing.add("Bahubali");
        nowShowing.add("Kabali");
        nowShowing.add("Luckky Di Unlukky Story");
        nowShowing.add("Sachin Billions Dream");
        nowShowing.add("Red 2");

        List<String> comingSoon = new ArrayList<String>();
        comingSoon.add("Tubelight ");
        comingSoon.add("Bahubali 3 2018");
        comingSoon.add("Dhoom 4");
        comingSoon.add("Hindi Medium");

        listDataChild.put(listDataHeader.get(0), weeks);
        listDataChild.put(listDataHeader.get(1), top250); // Header, Child data
        listDataChild.put(listDataHeader.get(2), nowShowing);
        listDataChild.put(listDataHeader.get(3), comingSoon);
    }
}


ExpandableListAdapter


package com.keshav.myexpandablelistviewexampleworkinginactivity;

import java.util.HashMap;
import java.util.List;

import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

public class ExpandableListAdapter extends BaseExpandableListAdapter {

    private Context _context;
    private List<String> _listDataHeader; // header titles
    // child data in format of header title, child title
    private HashMap<String, List<String>> _listDataChild;

    public ExpandableListAdapter(Context context, List<String> listDataHeader,
            HashMap<String, List<String>> listChildData) {
        this._context = context;
        this._listDataHeader = listDataHeader;
        this._listDataChild = listChildData;
    }

    @Override
    public Object getChild(int groupPosition, int childPosititon) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .get(childPosititon);
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public View getChildView(int groupPosition, final int childPosition,
            boolean isLastChild, View convertView, ViewGroup parent) {

        final String childText = (String) getChild(groupPosition, childPosition);

        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_item, null);
        }

        TextView txtListChild = (TextView) convertView
                .findViewById(R.id.lblListItem);

        txtListChild.setText(childText);
        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return this._listDataHeader.get(groupPosition);
    }

    @Override
    public int getGroupCount() {
        return this._listDataHeader.size();
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {
        String headerTitle = (String) getGroup(groupPosition);
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_group, null);
        }

        TextView lblListHeader = (TextView) convertView
                .findViewById(R.id.lblListHeader);
        lblListHeader.setTypeface(null, Typeface.BOLD);
        lblListHeader.setText(headerTitle);

        return convertView;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

}


activity_mail.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:background="#f4f4f4" >

            <ExpandableListView
                android:id="@+id/lvExp"
                android:layout_height="match_parent"
                android:layout_width="match_parent"
                android:cacheColorHint="#00000000"/>   

</LinearLayout>


list_grou.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="8dp" 
    android:background="#000000">


    <TextView
        android:id="@+id/lblListHeader"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
        android:textSize="17dp"
        android:textColor="#f9f93d" />

</LinearLayout>


list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="55dip"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/lblListItem"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="17dip"
        android:paddingTop="5dp"
        android:paddingBottom="5dp"
        android:textColor="#000000"
        android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft" />

</LinearLayout>