转到下一个文本框时清除文本框

Question

I created a text-box under expandable list. Everything works fine, But when i entered text in one text box, expend another and enter text in that, then previously entered text is clear. I don't know why this is happening, But help me.

Here is the code:-

MainActivity.java

     package info.androidhive.expandablelistview;

     import java.util.ArrayList;
     import java.util.HashMap;
     import java.util.List;
     import android.app.Activity;
     import android.os.Bundle;
     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;

     public class MainActivity extends Activity {

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

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

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

    // 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() {

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

    // 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();

        }
    });

    // 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 ArrayList<String>();

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

    // Adding child data
    List<String> top250 = new ArrayList<String>();
    top250.add("The Shawshank Redemption");
    top250.add("The Godfather");
    top250.add("The Godfather: Part II");
    top250.add("Pulp Fiction");
    top250.add("The Good, the Bad and the Ugly");
    top250.add("The Dark Knight");
    top250.add("12 Angry Men");

    List<String> nowShowing = new ArrayList<String>();
    nowShowing.add("The Conjuring");
    nowShowing.add("Despicable Me 2");
    nowShowing.add("Turbo");
    nowShowing.add("Grown Ups 2");
    nowShowing.add("Red 2");
    nowShowing.add("The Wolverine");

    List<String> comingSoon = new ArrayList<String>();
    comingSoon.add("2 Guns");
    comingSoon.add("The Smurfs 2");
    comingSoon.add("The Spectacular Now");
    comingSoon.add("The Canyons");
    comingSoon.add("Europa Report");
    listDataChild.add(listDataHeader.get(0)); // Header, Child data
    listDataChild.add(listDataHeader.get(1));
    listDataChild.add(listDataHeader.get(2));
}
}

ExpandableListAdapter.java

        package info.androidhive.expandablelistview;

        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 List<String> _listDataChild;

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

            @Override
            public Object getChild(int groupPosition, int childPosititon) {
                return null;
            }

            @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 1;
            }

            @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_main.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_group.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" >
            <EditText
                android:id="@+id/lblListItem"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:ems="10" >

                <requestFocus />
            </EditText>

        </LinearLayout>

Answer 1

you are missing code in getChild() Method

 @Override
        public Object getChild(int groupPosition, int childPosititon) {
            return null;
        }

chage to

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

Answer 2

您正在从getChild更改定义返回null

return this._listDataChild.get(childPosititon);