How to open sub menu after click on menu-item in Navigation drawer?

Question

I implemented a navigation drawer, with navigation view. and i am adding value in navigation view through a menu.xml file.

Answer 1

The best solution is to have an expandable list view in navigation view.See the code below activity_navigation_view.xml

The layout navigation header is as below navigation_view_header.xml

In your navigation view activity, set the adapter for the expandable list view. NavigationViewActivity.java

  public class NavigationViewActivity extends AppCompatActivity {
        private DrawerLayout mDrawerLayout;
        ExpandableListAdapter mMenuAdapter;
        ExpandableListView expandableList;
        List listDataHeader;
        HashMap> listDataChild;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_navigation_view);
    final ActionBar ab = getSupportActionBar();
    /* to set the menu icon image*/
    ab.setHomeAsUpIndicator(R.drawable.ic_menu);
    ab.setDisplayHomeAsUpEnabled(true);
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    expandableList= (ExpandableListView) findViewById(R.id.navigationmenu);
    NavigationView navigationView = (NavigationView)    findViewById(R.id.nav_view);

    if (navigationView != null) {
        setupDrawerContent(navigationView);
    }

    prepareListData();
    mMenuAdapter = new ExpandableListAdapter(this, listDataHeader,   listDataChild, expandableList);

    // setting list adapter
    expandableList.setAdapter(mMenuAdapter);
   }

    private void prepareListData() {
    listDataHeader = new ArrayList();
    listDataChild = new HashMap>();

    // Adding data header
    listDataHeader.add("heading1");
    listDataHeader.add("heading2");
    listDataHeader.add("heading3");

    // Adding child data
    List heading1= new ArrayList();
    heading1.add("Submenu of item 1");


    List heading2= new ArrayList();
    heading2.add("Submenu of item 2");
    heading2.add("Submenu of item 2");
    heading2.add("Submenu of item 2");


    listDataChild.put(listDataHeader.get(0), heading1);// Header, Child data
    listDataChild.put(listDataHeader.get(1), heading2);

   }
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            mDrawerLayout.openDrawer(GravityCompat.START);
            return true;
    }
    return super.onOptionsItemSelected(item);
}



private void setupDrawerContent(NavigationView navigationView) {
    navigationView.setNavigationItemSelectedListener(
            new NavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(MenuItem menuItem) {
                    menuItem.setChecked(true);
                    mDrawerLayout.closeDrawers();
                    return true;
                }
            });
}


@Override
public void onFragmentInteraction(Boolean isDataSaved) {

}
}

The adapter for expandable list view is as follows

   public class ExpandableListAdapter extends BaseExpandableListAdapter {
       private Context mContext;
       private List mListDataHeader; // header titles

       // child data in format of header title, child title
       private HashMap> mListDataChild;
       ExpandableListView  expandList;
   public ExpandableListAdapter(Context context, List listDataHeader,HashMap> listChildData,ExpandableListView mView) 
       {
         this.mContext = context;
         this.mListDataHeader = listDataHeader;
         this.mListDataChild = listChildData;
         this.expandList=mView;
       }

    @Override
     public int getGroupCount() {
       int i= mListDataHeader.size();
       Log.d("GROUPCOUNT",String.valueOf(i));
       return this.mListDataHeader.size();
      }

    @Override
     public int getChildrenCount(int groupPosition) {
     int childCount=0;
     if(groupPosition!=2) 
       {
 childCount=this.mListDataChild.get(this.mListDataHeader.get(groupPosition))
                .size();
       }
      return childCount;
       }

     @Override
      public Object getGroup(int groupPosition) {

      return this.mListDataHeader.get(groupPosition);
     }

    @Override
     public Object getChild(int groupPosition, int childPosition) {
   Log.d("CHILD",mListDataChild.get(this.mListDataHeader.get(groupPosition))
            .get(childPosition).toString());
    return this.mListDataChild.get(this.mListDataHeader.get(groupPosition))
            .get(childPosition);
    }

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

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

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

    @Override
     public View getGroupView(int groupPosition, boolean isExpanded, View   convertView, ViewGroup parent) {
       ExpandedMenuModel headerTitle = (ExpandedMenuModel) getGroup(groupPosition);
        if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this.mContext
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.listheader, null);
      }
       TextView lblListHeader = (TextView) convertView
            .findViewById(R.id.submenu);
       ImageView headerIcon=    (ImageView)convertView.findViewById(R.id.iconimage);
         lblListHeader.setTypeface(null, Typeface.BOLD);
         lblListHeader.setText(headerTitle.getIconName());
         headerIcon.setImageDrawable(headerTitle.getIconImg());
         return convertView;
     }

       @Override
        public View getChildView(int groupPosition, int childPosition,  boolean isLastChild, View convertView, ViewGroup parent) {
          final String childText = (String) getChild(groupPosition, childPosition);

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

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

      txtListChild.setText(childText);

      return convertView;
       }

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

      }

list_submenu.xml is as follows

listheader.xml is as follows

I have posted whole code for clarity. Hope this helps.......