android - How to display more than 3- levels of expandable List View?

Question

How to display more than 3- level of expandable list view, I am getting only examples for 3-Levels expandable.

Referring this :three-level-expandable-list

In this example he adding one more Expandable list in getChildView method of ParentLevel BaseExpandableListAdapter :

CustExpListview SecondLevelexplv = new CustExpListview(Home.this);
SecondLevelexplv.setAdapter(new SecondLevelAdapter());

SecondLevelexplv.setGroupIndicator(null);   
return SecondLevelexplv;

so Similarily I'am Adding one more Expandable list in the getChildView method of SecondLevelAdapter.

Its Working But View is not coming proper like 3- level of expandable list view. And I have Read this:

3-level-expandable-list-view-with-swipe-feature

multi-level-expandablelistview-in-android

issue-with-expanding-multi-level-expandablelistview

Please guideline or share me suitable example for Multi-level expandable display in android.

Thanks,

Answer 1

I Found Solution and I am uploading all java class So check all java Or U can check this :

1: MainActivity.java

public class MainActivity extends Activity {

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

    Object  obj = new Object();
    obj.children =  new ArrayList<Object>();
    for(int i = 0;i<Constant.state.length;i++)
    {
        Object root =  new Object();
        root.title = Constant.state[i];
        root.children =  new ArrayList<Object>();
        for(int j=0;j<Constant.parent[i].length;j++)
        {
             Object parent =  new Object();
             parent.title=Constant.parent[i][j];
             parent.children =  new ArrayList<Object>();
             for(int k=0;k<Constant.child[i][j].length;k++)
             {
                 Object child =  new Object();
                 child.title =Constant.child[i][j][k];
                 parent.children.add(child);
             }
             root.children.add(parent); 
        }
        obj.children.add(root);
    }

    if (!obj.children.isEmpty()) {
        final ExpandableListView elv = (ExpandableListView) findViewById(R.id.expList);

        elv.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {

            @Override
            public boolean onGroupClick(ExpandableListView parent, View v,
                    int groupPosition, long id) {

                return true; /* or false depending on what you need */;
            }
        });


        ExpandableListView.OnGroupClickListener grpLst = new ExpandableListView.OnGroupClickListener() {
            @Override
            public boolean onGroupClick(ExpandableListView eListView, View view, int groupPosition,
                    long id) {

                return true/* or false depending on what you need */;
            }
        };


        ExpandableListView.OnChildClickListener childLst = new ExpandableListView.OnChildClickListener() {
            @Override
            public boolean onChildClick(ExpandableListView eListView, View view, int groupPosition,
                    int childPosition, long id) {

                return true/* or false depending on what you need */;
            }
        };

        ExpandableListView.OnGroupExpandListener grpExpLst = new ExpandableListView.OnGroupExpandListener() {
            @Override
            public void onGroupExpand(int groupPosition) {

            }
        };

        final RootAdapter adapter = new RootAdapter(this, obj, grpLst, childLst, grpExpLst);
        elv.setAdapter(adapter);
}


}
 }

2: Object.java

public class Object {
public String title; // use getters and setters instead
public List<Object> children; // same as above

public Object() {
    children = new ArrayList<Object>();
}
}

3:RootAdapter.java

public class RootAdapter extends BaseExpandableListAdapter {

private Object root;

private final LayoutInflater inflater;

public class Entry {
    public final CustExpListview cls;
    public final SecondLevelAdapter sadpt;

    public Entry(CustExpListview cls, SecondLevelAdapter sadpt) {
        this.cls = cls;
        this.sadpt = sadpt;
    }
}

public Entry[] lsfirst;

public RootAdapter(Context context, Object root, ExpandableListView.OnGroupClickListener grpLst,
    ExpandableListView.OnChildClickListener childLst, ExpandableListView.OnGroupExpandListener grpExpLst) {
    this.root = root;
    this.inflater = LayoutInflater.from(context);

    lsfirst = new Entry[root.children.size()];

    for (int i = 0; i < root.children.size(); i++) {
        final CustExpListview celv = new CustExpListview(context);
        SecondLevelAdapter adp = new SecondLevelAdapter(root.children.get(i),context);
        celv.setAdapter(adp);
        celv.setGroupIndicator(null);
        celv.setOnChildClickListener(childLst);
        celv.setOnGroupClickListener(grpLst);
        celv.setOnGroupExpandListener(grpExpLst);

        lsfirst[i] = new Entry(celv, adp);
    }

}

@Override
public Object getChild(int groupPosition, int childPosition) {
    return root.children.get(groupPosition);
}

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

@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild,
    View convertView, ViewGroup parent) {
    // second level list
    return lsfirst[groupPosition].cls;
}

@Override
public int getChildrenCount(int groupPosition) {
    return 1;
}

@Override
public Object getGroup(int groupPosition) {
    return root.children.get(groupPosition);
}

@Override
public int getGroupCount() {
    return root.children.size();
}

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

@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
    ViewGroup parent) {

    // first level

    View layout = convertView;
    GroupViewHolder holder;
    final Object item = (Object) getGroup(groupPosition);

    if (layout == null) {
        layout = inflater.inflate(R.layout.item_root, parent, false);
        holder = new GroupViewHolder();
        holder.title = (TextView) layout.findViewById(R.id.itemRootTitle);
        layout.setTag(holder);
    } else {
        holder = (GroupViewHolder) layout.getTag();
    }

    holder.title.setText(item.title.trim());

    return layout;
}

private static class GroupViewHolder {
    TextView title;
}

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

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

4: SecondLevelAdapter.java

public class SecondLevelAdapter extends BaseExpandableListAdapter {

public Object child;
Context mContext;
LayoutInflater inflater;

public SecondLevelAdapter(Object child,Context context) {
    this.child = child;
    this.mContext=context;
    inflater = LayoutInflater.from(mContext);
}

@Override
public Object getChild(int groupPosition, int childPosition) {
    return child.children.get(groupPosition).children.get(childPosition);
}

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

// third level
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild,
        View convertView, ViewGroup parent) {
    View layout = convertView;
    final Object item = (Object) getChild(groupPosition, childPosition);

    ChildViewHolder holder;

    if (layout == null) {
        layout = inflater.inflate(R.layout.item_child, parent, false);

        holder = new ChildViewHolder();
        holder.title = (TextView) layout.findViewById(R.id.itemChildTitle);
        layout.setTag(holder);
    } else {
        holder = (ChildViewHolder) layout.getTag();
    }

    holder.title.setText(item.title.trim());

    return layout;
}

@Override
public int getChildrenCount(int groupPosition) {
    return child.children.get(groupPosition).children.size();
}

@Override
public Object getGroup(int groupPosition) {
    return child.children.get(groupPosition);
}

@Override
public int getGroupCount() {
    return child.children.size();
}

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

// Second level
@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
        ViewGroup parent) {
    View layout = convertView;
    ViewHolder holder;

    final Object item = (Object) getGroup(groupPosition);

    if (layout == null) {
        layout = inflater.inflate(R.layout.item_parent, parent, false);
        holder = new ViewHolder();
        holder.title = (TextView) layout.findViewById(R.id.itemParentTitle);
        layout.setTag(holder);
    } else {
        holder = (ViewHolder) layout.getTag();
    }

    holder.title.setText(item.title.trim());

    return layout;
}

@Override
public void registerDataSetObserver(DataSetObserver observer) {
    super.registerDataSetObserver(observer);
}

@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
    Log.d("SecondLevelAdapter", "Unregistering observer");
    if (observer != null) {
        super.unregisterDataSetObserver(observer);
    }
}

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

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

private static class ViewHolder {
    TextView title;
}

private static class ChildViewHolder {
    TextView title;
}

}

5 Constant.java

public class Constant {
static String[] state = {"A","B","C"};
static  String[][] parent = {
        {"aa","bb","cc","dd","ee"},
        {"ff","gg","hh","ii","jj"},
        {"kk","ll","mm","nn","oo"}
    };

static  String[][][] child = {
            {
                {"aaa","aab","aac","aad","aae"},
                {"bba","bbb","bbc","bbd","bbe"},
                {"cca","ccb","ccc","ccd","cce","ccf","ccg"},
                {"dda","ddb","dddc","ddd","dde","ddf"},
                {"eea","eeb","eec"}
            },
            {
                {"ffa","ffb","ffc","ffd","ffe"},
                {"gga","ggb","ggc","ggd","gge"},
                {"hha","hhb","hhc","hhd","hhe","hhf","hhg"},
                {"iia","iib","iic","iid","iie","ii"},
                {"jja","jjb","jjc","jjd"}
            },
            {
                {"kka","kkb","kkc","kkd","kke"},
                {"lla","llb","llc","lld","lle"},
                {"mma","mmb","mmc","mmd","mme","mmf","mmg"},
                {"nna","nnb","nnc","nnd","nne","nnf"},
                {"ooa","oob"}
            }
        };
}

5: item_parent.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="wrap_content"
android:orientation="horizontal"
android:paddingLeft="10dp" >

<TextView
    android:id="@+id/itemParentTitle"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="wrap_content"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:background="#5ccccc"
    android:padding="2dp"
    android:textColor="#006363"
    android:textSize="20sp" />

<ImageView
    android:id="@+id/itemParentImage"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

</LinearLayout>