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I'm just starting out in Android development and need to create an expandable list view. I'm following this tutorial: http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/

The application compiles and runs successfully, however I'm getting the following error:

java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView

I have found similar issues on the website, as well as read the Array Adapter documentation, and it seems that I should either:

A) "Provide a single TextView as a resource id. (which I don't want to do, as I want to create a custom layout with an ImageView)"

-or-

B) "Use the constructors that also takes a field id. That field id should reference a TextView in the larger layout resource."

My problem is that the mentioned tutorial doesn't use a simple ArrayAdapter, but a BaseExpandableListAdapter, whose constructor doesn't really accept any paramaters it seems? Where should I pass the reference to the TextView with a BaseExpandableListAdapter?

I'm extending it as follows:

package net.jekyllhyde.myapplication;

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;

import java.util.HashMap;
import java.util.List;

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, parent, false);
        }

        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, parent, false);
        }

        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;
    }
}

I think I'm missing something obvious here (due to my lack of experience with Android) and am thankful for any insight.

Entire logcat error output, as requested:

02-15 09:51:11.509  10170-10170/? E/AndroidRuntime? FATAL EXCEPTION: main
Process: net.jekyllhyde.myapplication, PID: 10170
java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView
        at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:386)
        at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
        at android.widget.AbsListView.obtainView(AbsListView.java:2263)
        at android.widget.ListView.makeAndAddView(ListView.java:1790)
        at android.widget.ListView.fillDown(ListView.java:691)
        at android.widget.ListView.fillFromTop(ListView.java:752)
        at android.widget.ListView.layoutChildren(ListView.java:1630)
        at android.widget.AbsListView.onLayout(AbsListView.java:2091)
        at android.view.View.layout(View.java:14965)
        at android.view.ViewGroup.layout(ViewGroup.java:4631)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
        at android.view.View.layout(View.java:14965)
        at android.view.ViewGroup.layout(ViewGroup.java:4631)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
        at android.view.View.layout(View.java:14965)
        at android.view.ViewGroup.layout(ViewGroup.java:4631)
        at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:374)
        at android.view.View.layout(View.java:14965)
        at android.view.ViewGroup.layout(ViewGroup.java:4631)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
        at android.view.View.layout(View.java:14965)
        at android.view.ViewGroup.layout(ViewGroup.java:4631)
        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1991)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1748)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5692)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
        at android.view.Choreographer.doCallbacks(Choreographer.java:574)
        at android.view.Choreographer.doFrame(Choreographer.java:544)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:212)
        at android.app.ActivityThread.main(ActivityThread.java:5151)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:684)
        at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.TextView
            at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:379) at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
at android.widget.AbsListView.obtainView(AbsListView.java:2263)
            at android.widget.ListView.makeAndAddView(ListView.java:1790)
            at android.widget.ListView.fillDown(ListView.java:691)
            at android.widget.ListView.fillFromTop(ListView.java:752)
            at android.widget.ListView.layoutChildren(ListView.java:1630)
            at android.widget.AbsListView.onLayout(AbsListView.java:2091)
            at android.view.View.layout(View.java:14965)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
            at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
            at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
            at android.view.View.layout(View.java:14965)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
            at android.view.View.layout(View.java:14965)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:374)
            at android.view.View.layout(View.java:14965)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
            at android.view.View.layout(View.java:14965)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1991)
            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1748)
            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5692)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
            at android.view.Choreographer.doCallbacks(Choreographer.java:574)
            at android.view.Choreographer.doFrame(Choreographer.java:544)
            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:212)
            at android.app.ActivityThread.main(ActivityThread.java:5151)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:684)
            at dalvik.system.NativeStart.main(Native Method)
Community
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Bragolgirith
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  • Hi, could you please post the entire logcat of this error and also the line of code where the app is crashing ? thanks – Yash Sampat Feb 15 '15 at 14:15
  • The crash log indicates it has nothing to do with your custom adapter. It's where ever you are using an ArrayAdapter. Can you post the relevant code segment where you are instantiating the adapter? – Ifrit Feb 15 '15 at 15:06
  • I'm not actually instantiating the ArrayAdapter myself (also, in the tutorial there's no mention of an ArrayAdapter - it just says to extend from the BaseExpandableListAdapter). – Bragolgirith Feb 15 '15 at 15:19
  • 1
    Right. But somewhere there is an ArrayAdapter being instantiated. You can't get that crash report when using an ExpandableListView with an ExpandableListAdapter. – Ifrit Feb 15 '15 at 15:28
  • Perhaps it'll help if you post the relevant Activity/Fragment this crash is happening in – Ifrit Feb 15 '15 at 15:34
  • Ok, update time. Just as you said - it had nothing to do with the adapter. What (I presume) happened was Android Studio building another project with a different project location but the same application name - I had a bunch of them in the same folder for all the different ListView tutorials I tried. After deleting all other projects with the same name it now runs fine. Thank you for your help - you definitely helped me get unstuck - and sorry for taking up your time. – Bragolgirith Feb 15 '15 at 16:15
  • Glad to have helped. That's what SO is here for. :-) – Ifrit Feb 15 '15 at 16:22

1 Answers1

1

Well the BaseExpandableListAdapter, which I think is the best way to implement an expandable listview, is an abstract class, you got to make a class by yourself that extends it and implement the methods, you can implement the constructor with the parameters you need as well as override the other methods like getChildView, getGroupView in order to make it work just the way you need.

Like this: http://numberedmountain.blogspot.com.es/p/code-example-overriding.html

EDIT: Just a heads up: even if you solve this current error, your ExpandableListView wont work properly since in the getGroupView method you have to take the isExpanded variable into account in order to return the view of the group either expanded or collapsed based on the value. Other than that I think you made it right, the error is unrelated as someone said in comments.

CyborgFish
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