片段中的 ExpandableListView

Question

我正在尝试在 Fragments 中实现 ExpandableListView。我已经测试了所有设置为 toast 的值，它工作正常。但我的 ExpandableListView 不显示。我没有收到任何错误。我在下面粘贴了我的代码。

 package com.test.expandablelistView;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    import com.example.tesfragement.R;
    import com.example.tesfragement.R.layout;
    import android.os.Bundle;
    import android.app.Fragment;
    import android.database.DataSetObserver;
    import android.support.v4.app.FragmentActivity;
    import android.view.Gravity;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ExpandableListAdapter;
    import android.widget.ExpandableListView;
    import android.widget.SimpleExpandableListAdapter;
    import android.widget.Toast;

    /**
     * A simple {@link android.support.v4.app.Fragment} subclass.
     * 
     */

    public class ExpandableListFragment extends Fragment {

        View v;
         ExpandableListAdapter mAdapter;
        List<String> _listDataHeader;
        HashMap<String, List<String>> _listDataChild;
        private Parent parent;
        private Child child;
        ExpandableListView lv;




        public ExpandableListFragment() {
            // Required empty public constructor

        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            // Inflate the layout for this fragment
            v= inflater.inflate(R.layout.expandable_fragements,
                    container, false);


            return v;
        }


        @Override
        public void onActivityCreated(Bundle savedInstanceState) {
            // TODO Auto-generated method stub

            super.onActivityCreated(savedInstanceState);
            parent=new Parent();
            child=new Child();
             ExpandableListView lv = (ExpandableListView) v.findViewById(R.id.expandableListView1);

             //here setting all the values to Parent and child classes
             setDataValues();
             prepareListData();//here get the values and set this values to adoptor and set it visible


             mAdapter=new ExpandableListAdapter() {

                @Override
                public void unregisterDataSetObserver(DataSetObserver observer) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello", Toast.LENGTH_LONG).show();

                }

                @Override
                public void registerDataSetObserver(DataSetObserver observer) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello1", Toast.LENGTH_LONG).show();
                }

                @Override
                public void onGroupExpanded(int groupPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello2", Toast.LENGTH_LONG).show();
                }

                @Override
                public void onGroupCollapsed(int groupPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello3", Toast.LENGTH_LONG).show();
                }

                @Override
                public boolean isEmpty() {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello4", Toast.LENGTH_LONG).show();
                    return false;
                }

                @Override
                public boolean isChildSelectable(int groupPosition, int childPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello5", Toast.LENGTH_LONG).show();
                    return false;
                }

                @Override
                public boolean hasStableIds() {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello6", Toast.LENGTH_LONG).show();
                    return false;
                }

                @Override
                public View getGroupView(int groupPosition, boolean isExpanded,
                        View convertView, ViewGroup parent) {
                    Toast.makeText(getActivity(),"hello7", Toast.LENGTH_LONG).show();
                    // TODO Auto-generated method stub
                    return v;
                }

                @Override
                public long getGroupId(int groupPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello8", Toast.LENGTH_LONG).show();
                    return 0;
                }

                @Override
                public int getGroupCount() {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello9", Toast.LENGTH_LONG).show();
                    return 0;
                }

                @Override
                public Object getGroup(int groupPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello10", Toast.LENGTH_LONG).show();
                    return null;
                }

                @Override
                public long getCombinedGroupId(long groupId) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello11", Toast.LENGTH_LONG).show();
                    return 0;
                }

                @Override
                public long getCombinedChildId(long groupId, long childId) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello12", Toast.LENGTH_LONG).show();
                    return 0;
                }

                @Override
                public int getChildrenCount(int groupPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello13", Toast.LENGTH_LONG).show();
                    return 0;
                }

                @Override
                public View getChildView(int groupPosition, int childPosition,
                        boolean isLastChild, View convertView, ViewGroup parent) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello14", Toast.LENGTH_LONG).show();
                    return v;
                }

                @Override
                public long getChildId(int groupPosition, int childPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello15", Toast.LENGTH_LONG).show();
                    return 0;
                }

                @Override
                public Object getChild(int groupPosition, int childPosition) {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello16", Toast.LENGTH_LONG).show();
                    return null;
                }

                @Override
                public boolean areAllItemsEnabled() {
                    // TODO Auto-generated method stub
                    Toast.makeText(getActivity(),"hello17", Toast.LENGTH_LONG).show();
                    return false;
                }
            };

               // mAdapter = new ExpandableListAdapter(this, _listDataHeader, _listDataChild);

                // setting list adapter
                lv.setAdapter(mAdapter);



        }


        public void prepareListData()
        {
            // testing purpose
            _listDataHeader = new ArrayList<String>();
            _listDataChild = new HashMap<String, List<String>>();


            // declare the references
            //add the parent values to List
            _listDataHeader.add(parent.getCardName());
            _listDataHeader.add(String.valueOf(parent.getMinimum_salary()));
            _listDataHeader.add(String.valueOf(parent.getInterest_rate()));


            //set Child views to parent
            List<String> cardDetails=new ArrayList<String>();
            cardDetails.add("");

            List<String> mininum_sal_details=new ArrayList<String>();
            mininum_sal_details.add(child.GetMinimumSalDetails());

            List<String> interest_details=new ArrayList<String>();
            interest_details.add(child.get_interest_rate_details());

            //set to adoptor

            _listDataChild.put(_listDataHeader.get(0),  cardDetails);
            _listDataChild.put(_listDataHeader.get(1),mininum_sal_details);

            //

             for(int i = 0; i < _listDataHeader.size(); i++) //cars name of arraylist
                {
                   String value=_listDataHeader.get(i);  
                   Toast toast = Toast.makeText(getActivity(),value, Toast.LENGTH_LONG);
                   toast.setGravity(Gravity.CENTER, 0, 0);
                   toast.show();

                }



        }

        public void setDataValues()
        {
            //set Parent values
            parent.setCardName("Platinum credit Card");
            parent.setMinimum_salary(15000.00);
            parent.setInterest_Rate(1.2);

            //set Child values
            child.set_card_details("You require minimum salary of 1500 per month");
            child.set_interest_rate_details("interest rate is 2.0%");


        }
    }

Answer 1

请检查此代码。

package com.test.expandablelistView;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.example.tesfragement.R;
import com.example.tesfragement.R.layout;
import android.os.Bundle;
import android.app.Fragment;
import android.content.Context;
import android.database.DataSetObserver;
import android.graphics.Typeface;
import android.support.v4.app.FragmentActivity;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.SimpleExpandableListAdapter;
import android.widget.TextView;
import android.widget.Toast;

/**
 * A simple {@link android.support.v4.app.Fragment} subclass.
 * 
 */

public class ExpandableListFragment extends Fragment {

    View v;
     ExpandableListAdapter mAdapter;
    List<String> _listDataHeader;
    HashMap<String, List<String>> _listDataChild;
    private Parent parent;
    private Child child;
    ExpandableListView lv;
    Context con;
    public ExpandableListFragment() {
        // Required empty public constructor

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        v= inflater.inflate(R.layout.expandable_fragements,
                container, false);

        return v;
    }


    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        super.onActivityCreated(savedInstanceState);
        parent=new Parent();
        child=new Child();
         ExpandableListView lv = (ExpandableListView) v.findViewById(R.id.expandableListView1);

         //here setting all the values to Parent and child classes
         setDataValues();
         prepareListData();//here get the values and set this values to adoptor and set it visible
         con=getActivity();

         mAdapter=new ExpandabelListAdoptor(con,_listDataHeader, _listDataChild) ; //here i didnt set list values to this adoptor

           // mAdapter = new ExpandableListAdapter(this, _listDataHeader, _listDataChild);

            // setting list adapter
            lv.setAdapter(mAdapter);

    }

    public void prepareListData()
    {
        // testing purpose
        _listDataHeader = new ArrayList<String>();
        _listDataChild = new HashMap<String, List<String>>();


        // declare the references
        //add the parent values to List
        _listDataHeader.add(parent.getCardName());
        _listDataHeader.add(String.valueOf(parent.getMinimum_salary()));
        _listDataHeader.add(String.valueOf(parent.getInterest_rate()));


        //set Child views to parent
        List<String> cardDetails=new ArrayList<String>();
        cardDetails.add("");

        List<String> mininum_sal_details=new ArrayList<String>();
        mininum_sal_details.add(child.GetMinimumSalDetails());

        List<String> interest_details=new ArrayList<String>();
        interest_details.add(child.get_interest_rate_details());

        //set to adoptor

        _listDataChild.put(_listDataHeader.get(0),  cardDetails);
        _listDataChild.put(_listDataHeader.get(1),mininum_sal_details);

        //

         for(int i = 0; i < _listDataHeader.size(); i++) //cars name of arraylist
            {
               String value=_listDataHeader.get(i);  
               Toast toast = Toast.makeText(getActivity(),value, Toast.LENGTH_LONG);
               toast.setGravity(Gravity.CENTER, 0, 0);
               toast.show();

            }
    }

    public void setDataValues()
    {
        //set Parent values
        parent.setCardName("Platinum credit Card");
        parent.setMinimum_salary(15000.00);
        parent.setInterest_Rate(1.2);

        //set Child values
        child.set_card_details("You require minimum salary of 1500 per month");
        child.set_interest_rate_details("interest rate is 2.0%");
    }

}
class ExpandabelListAdoptor extends BaseExpandableListAdapter
{

    private Context _context;
    private List<String> _listDataHeader;
    private HashMap<String, List<String>> _listDataChild;

    ExpandabelListAdoptor(Context con,List<String> listDataHeader ,HashMap<String, List<String>>  listDataChild )
    {
        this._context=con;

        this._listDataChild=listDataChild;
        this._listDataHeader=listDataHeader;
    }

    @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) {
        // TODO Auto-generated method stub
         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) {
        // TODO Auto-generated method stub
         return this._listDataHeader.get(groupPosition);
    }

    @Override
    public int getGroupCount() {
        // TODO Auto-generated method stub
        return this._listDataHeader.size();
    }

    @Override
    public long getGroupId(int groupPosition) {
        // TODO Auto-generated method stub
         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() {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return true;
    }

}

Answer 2

如果getGroupCount 返回 0，屏幕上不会显示任何内容，因为不会调用 getGroupView 方法。孩子们也一样