ExpandableLists in Android, I want to allow only one parent list to expand at a time

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难免孤独
难免孤独 2021-02-04 17:15

I want to make only one item in the parent list expand at a time, my code for the onCreate is currently the following. (It works as I want, But the method to allow only one pare

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  • 2021-02-04 17:30
        @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);
                }
            }
        }
    
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  • 2021-02-04 17:35

    Its Working See Screen Shots

    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>
    
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  • 2021-02-04 17:42

    Modified the answer from Iram: So you can reopen the same Group

    // Listview Group expanded listener
        expListView.setOnGroupExpandListener(new OnGroupExpandListener() {
    
            @Override
            public void onGroupExpand(int groupPosition) {
                if (prevouriousExpandedGroupNumber != -1 && prevouriousExpandedGroupNumber != groupPosition) {
                    expListView.collapseGroup(prevouriousExpandedGroupNumber);
                }
                prevouriousExpandedGroupNumber = groupPosition;
            }
        });
    
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  • 2021-02-04 17:43

    I believe a straight forward solution would be to implement one Adapter to handle any of the events you are interested in.

    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);
            }
        }
      }
    }
    

    By separating the list adapter into another class you will not clutter the Activity code with one-off listener implementations. Instead, in each Activity simply instantiate the adapter and set it on the list

    @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;
    }
    
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  • 2021-02-04 17:44

    The problem was solved by creating a public explist variable called list, and then referencing it to the adapter in view with the following call.

    list = getExpandableListView(); 
    

    The expand method before was crashing the app because of this. After refferencing the list.collapsegroup in, it worked fine.

    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);
                                }
                            }
    
                        }
                }
    
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  • 2021-02-04 17:53
    // 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;
                }
            });
    

    Updating with updated solution

    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;
        }
    });
    
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