CODEWITHSUNDEEP
javaandroidandroid-listview
MrZnyper
MrZnyper

Reputation: 1

Android ListView throws NullPointer exception on click

I have the following code which correctly adds the series name to aName and link to aLink so both ArrayLists hold values. When run the ListView correctly displays aName, but when one of the items in the listview is clicked the app throws the NullPointer exeption.

    public class MainActivity extends ListActivity {
ArrayAdapter<String> adapter;
ArrayList aName;
ArrayList aLink;
ListView view;
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    view = getListView();
    view.setTextFilterEnabled(true);
    //CONNECT CODE//
    Document main = Jsoup.parse("<html> </html>");
    try {
        main = Jsoup.connect("http://www.animeseason.com/anime-list/").get();
    } catch (IOException e) {
        AlertDialog alertDialog;
        alertDialog = new AlertDialog.Builder(this).create();
        alertDialog.setTitle("Connection Error");
        alertDialog.setMessage("Could not Connect.");
        alertDialog.show();
        e.printStackTrace();
    }
    //PARSE HTML CODE//
    aName = new ArrayList();
    aLink = new ArrayList();
    main = Jsoup.parse(main.getElementsByClass("series_col").toString());
    Elements seriesL = main.getElementsByTag("li");
    for(Element anime: seriesL){
        Elements link = anime.getElementsByTag("a");
        aName.add(link.text());
        aLink.add(link.attr("href"));
    }
    //SET VIEW//
    adapter = new ArrayAdapter<String>(this, R.layout.list_item, aName);
    setListAdapter(adapter);
    //ONCLICK
    view.setOnItemClickListener(
        new OnItemClickListener(){
        public void onItemClick(AdapterView<?> arg0, View view, int position, long arg3) {
             Intent myIntent = new Intent(view.getContext(), EpisodeListActivity.class);
             String name = (String) aName.get(position).toString();
             String link = (String) aLink.get(position).toString();
             myIntent.putExtra("Anime", name);
             myIntent.putExtra("Link", link);
             startActivity(myIntent);
        }
    });

}

Here's the log-

    07-04 15:08:15.382: W/dalvikvm(3489): threadid=1: thread exiting with uncaught                 exception (group=0x40a3c1f8)
    07-04 15:08:15.406: E/AndroidRuntime(3489): FATAL EXCEPTION: main
    07-04 15:08:15.406: E/AndroidRuntime(3489): java.lang.NullPointerException
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:394)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.AbsListView.obtainView(AbsListView.java:2035)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.ListView.makeAndAddView(ListView.java:1772)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.ListView.fillDown(ListView.java:672)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.ListView.fillFromTop(ListView.java:732)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.ListView.layoutChildren(ListView.java:1625)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.AbsListView.onLayout(AbsListView.java:1865)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.View.layout(View.java:11278)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.ViewGroup.layout(ViewGroup.java:4224)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.View.layout(View.java:11278)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.ViewGroup.layout(ViewGroup.java:4224)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.LinearLayout.onLayout(LinearLayout.java:1399)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.View.layout(View.java:11278)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.ViewGroup.layout(ViewGroup.java:4224)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.View.layout(View.java:11278)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.ViewGroup.layout(ViewGroup.java:4224)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1489)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.os.Handler.dispatchMessage(Handler.java:99)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.os.Looper.loop(Looper.java:137)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at android.app.ActivityThread.main(ActivityThread.java:4424)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at java.lang.reflect.Method.invokeNative(Native Method)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at java.lang.reflect.Method.invoke(Method.java:511)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)
    07-04 15:08:15.406: E/AndroidRuntime(3489):     at dalvik.system.NativeStart.main(Native Method)

Upvotes: 0

Views: 1027

Answers (2)

marnaish
marnaish

Reputation: 2286

You could also create a "normal" Activity instead of a ListActivity.

public class MainActivity extends Activity {
...

Change the ListViews id in your xml layout to "@+id/list".

<ListView
    android:id="@+id/list"
...

Or create your list view in your onCreate method:

ListView listView = new ListView(this);
setContentView(listView);

Get the ListView and you can use the OnItemClickListener.

ListView listView = (ListView) findViewById(R.id.list); // only needed if you have a xml layout
listView.setAdapter(adapter);
listView.setOnItemClickListener( ...

Upvotes: 0

10s
10s

Reputation: 1699

You are extending ListActivity, override the method onListItemClick() in Activity instead of view.setOnItemClickListener that you are doing in onCreate()

EDIT:

in your layout xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
   <ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />
</LinearLayout>

in your activity that uses the layout:

in class: public class MyActivity extends ListActivity

getting the list view: ListView list = getListView();

setting the list adapter: setListAdapter(adapter);

inside MyActivity class override the onListItemClick: 

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
//do your thing 
}

documentation: http://developer.android.com/reference/android/app/ListActivity.html

Upvotes: 1

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