notifyDataSetChanged() causes IndexOutOfBoundsException

Question

Here's a shortened version of my code.

public class MainActivity extends ActionBarActivity {

private ArrayList<String> entry = new ArrayList<String>();
private String[] entryString = new String[11];
private ArrayAdapter<String> aa;
private ListView entryListView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    entryListView = (ListView) findViewById(R.id.listView1);
    int listID = R.layout.entry_layout;
    aa = new EntryAdapter(this, listID, entry);
    entryListView.setAdapter(aa);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    switch (id) {
    case R.id.action_add: {
        Intent intent = new Intent(MainActivity.this, AddActivity.class);
        startActivityForResult(intent, 1);
        break;
    }
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onActivityResult(int rc, int resc, Intent i) {
    super.onActivityResult(rc, resc, i);
    entryString = i.getStringArrayExtra("Entry");
    this.onNewItemAdded(entryString);
}

public void onNewItemAdded(String[] _entry){
    String key = new String();
    key = _entry[0];
    entry.add(key);
    aa.notifyDataSetChanged();   //Runs without crashing when this is removed.
}

The adapter class is,

@SuppressLint("Instantiatable")
public class EntryAdapter extends ArrayAdapter<String>{

private ArrayList<String> entries;
int count;
int resource;
public EntryAdapter(Context _context, int _resource, List<String> _entries){
    //TODO Auto-generated constructor stub
    super(_context, _resource, R.id.key, _entries);
    this.resource = _resource;
    this.entries = new ArrayList<String>(_entries);
    this.count = 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;

    if (convertView == null) {
        String inflater = Context.LAYOUT_INFLATER_SERVICE;
        LayoutInflater li;
        li = (LayoutInflater) getContext().getSystemService(inflater);
        row = li.inflate(resource, parent, false);
    }

    TextView keyView = (TextView) row.findViewById(R.id.key);
    TextView siteView = (TextView) row.findViewById(R.id.site);

    for(int c=0; c<11; c++){
        while(!entries.get(c).toString().equals("")){
            count++;
        }
    }

    keyView.setText(entries.get(position));
    siteView.setText(count + "sources");

    return row;
}
} 

By commenting the aa.notifyDataSetChanged() call in the MainActivity, the application runs without crashing but throws an

IndexOutOfBoundsException: Invalid index 0, size is 0

when it is not commented.

PS: The XML is perfectly fine.

Edit:

Here's the log

03-18 18:38:03.840: E/AndroidRuntime(6052): FATAL EXCEPTION: main 03-18 18:38:03.840: E/AndroidRuntime(6052): Process: com.FirstClass.alert, PID: 6052 03-18 18:38:03.840: E/AndroidRuntime(6052): java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0 03-18 18:38:03.840: E/AndroidRuntime(6052): at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255) 03-18 18:38:03.840: E/AndroidRuntime(6052): at java.util.ArrayList.get(ArrayList.java:308) 03-18 18:38:03.840: E/AndroidRuntime(6052): at com.FirstClass.netalert.EntryAdapter.getView(EntryAdapter.java:66) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.AbsListView.obtainView(AbsListView.java:2263) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.ListView.makeAndAddView(ListView.java:1790) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.ListView.fillDown(ListView.java:691) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.ListView.fillFromTop(ListView.java:752) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.ListView.layoutChildren(ListView.java:1630) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.AbsListView.onLayout(AbsListView.java:2091) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.View.layout(View.java:14822) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewGroup.layout(ViewGroup.java:4631) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1055) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.View.layout(View.java:14822) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewGroup.layout(ViewGroup.java:4631) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.FrameLayout.onLayout(FrameLayout.java:388) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.View.layout(View.java:14822) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewGroup.layout(ViewGroup.java:4631) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.support.v7.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:502) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.View.layout(View.java:14822) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewGroup.layout(ViewGroup.java:4631) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.FrameLayout.onLayout(FrameLayout.java:388) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.View.layout(View.java:14822) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewGroup.layout(ViewGroup.java:4631) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.LinearLayout.onLayout(LinearLayout.java:1434) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.View.layout(View.java:14822) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewGroup.layout(ViewGroup.java:4631) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.widget.FrameLayout.onLayout(FrameLayout.java:388) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.View.layout(View.java:14822) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewGroup.layout(ViewGroup.java:4631) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1987) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1744) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.Choreographer.doCallbacks(Choreographer.java:574) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.Choreographer.doFrame(Choreographer.java:544) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.os.Handler.handleCallback(Handler.java:733) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.os.Handler.dispatchMessage(Handler.java:95) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.os.Looper.loop(Looper.java:136) 03-18 18:38:03.840: E/AndroidRuntime(6052): at android.app.ActivityThread.main(ActivityThread.java:5021) 03-18 18:38:03.840: E/AndroidRuntime(6052): at java.lang.reflect.Method.invokeNative(Native Method) 03-18 18:38:03.840: E/AndroidRuntime(6052): at java.lang.reflect.Method.invoke(Method.java:515) 03-18 18:38:03.840: E/AndroidRuntime(6052): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:827) 03-18 18:38:03.840: E/AndroidRuntime(6052): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:643) 03-18 18:38:03.840: E/AndroidRuntime(6052): at dalvik.system.NativeStart.main(Native Method)

Answer 1

If you are creating a new ArrayList by calling new ArrayList<String>(_entries); your ArrayList in your activity will not be referenced by the ArrayList in your Adapter. So when you change the entry Arraylist in your activity it will not effect the Adapters ArrayList. Either change the constructor to:

public EntryAdapter(Context _context, int _resource, List<String> _entries){
    super(_context, _resource, R.id.key, _entries);
    this.resource = _resource;
    this.entries = _entries;
    this.count = 0;
}

or change the onNewItemAdded to:

public void onNewItemAdded(String[] _entry){
    String key = new 
    key = _entry[0];
    aa.add(key);
    aa.notifyDataSetChanged();
}