NULL POINTER EXCEPTION for arrayadapter in listview. ANDROID

Question

I have a main view(listview) and a second main view(edittext). I pass data from second main view backwards to first main view using startActivityforResult(). I have tested it out and I recieve the string back with no problem. However there are some problems displaying it on listview. My listview has two xml files one for the listview layout and one for the textview row. I have no idea why I am getting a nullpointer exception.

03-14 22:50:33.429    9268-9268/com.example.anusha.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.anusha.app, PID: 9268
java.lang.NullPointerException
        at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:392)
        at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
        at android.widget.AbsListView.obtainView(AbsListView.java:2780)
        at android.widget.ListView.measureHeightOfChildren(ListView.java:1274)
        at android.widget.ListView.onMeasure(ListView.java:1186)
        at android.view.View.measure(View.java:17594)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5398)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
        at android.view.View.measure(View.java:17594)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5398)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at android.view.View.measure(View.java:17594)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5398)
        at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
        at android.view.View.measure(View.java:17594)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5398)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at android.view.View.measure(View.java:17594)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5398)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
        at android.view.View.measure(View.java:17594)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5398)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2588)
        at android.view.View.measure(View.java:17594)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2308)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2030)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1267)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6640)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:813)
        at android.view.Choreographer.doCallbacks(Choreographer.java:613)
        at android.view.Choreographer.doFrame(Choreographer.java:583)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:799)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:146)
        at android.app.ActivityThread.main(ActivityThread.java:5635)
        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:1291)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
        at dalvik.system.NativeStart.main(Native Method)

Here is my first main view with my listview. I'm pretty sure the problem is with the arrayadapter. Don't know what it is though.

 ArrayList<String> array= new ArrayList<>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_address_list);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    ArrayAdapter<String> adapter = new ArrayAdapter<>(this, R.layout.activity_address_list,R.id.rowTextView, array);
    ListView listview = (ListView) findViewById(R.id.listView);
    listview.setAdapter(adapter);



}
private void Add() {
    Intent intent = new Intent(AddressList.this, SilentGeofence.class);
    startActivityForResult(intent, 2);

}

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 2) {
        if (resultCode == RESULT_OK){
            String result = data.getStringExtra("result");
            array.add(result);


        }
    }
    }

Here is my second main

   Button add = (Button) findViewById(R.id.button);
    add.setOnClickListener(new View.OnClickListener() {

        public void onClick(View view) {

            String ag = txt1.getText().toString().trim();
                txt1.setText("");
                Intent returnIntent = new Intent();
                returnIntent.putExtra("result",ag);
                setResult(RESULT_OK,returnIntent);
                finish();

array is not populated with items. Where do you call Add()?? — Raghunandan
– Raghunandan, Commented Mar 15, 2015 at 6:10
your problem is ArrayAdapter<String> adapter = new ArrayAdapter<>(this, R.layout.activity_address_list,R.id.rowTextView, array);. read documentation to how to populate arrayAdapter — Shayan Pourvatan
– Shayan Pourvatan, Commented Mar 15, 2015 at 6:11
i call Add() onOptionsItemSelected() in menu.It's one of my bar button items. @Raghunandan — anu
– anu, Commented Mar 15, 2015 at 6:12
I am using public ArrayAdapter (Context context, int resource, int textViewResourceId, T[] objects) @shayanpourvatan — anu
– anu, Commented Mar 15, 2015 at 6:16
The array is getting items from the second main and getting updated in onActivityResult() right? — anu
– anu, Commented Mar 15, 2015 at 6:17

krishna · Accepted Answer · 2015-03-15 06:48:40Z

3

public ArrayAdapter (Context context, int resource, int textViewResourceId, T[] objects)

Added in API level 1 Constructor

Parameters context The current context. resource The resource ID for a layout file containing a layout to use when instantiating views. textViewResourceId The id of the TextView within the layout resource to be populated objects The objects to represent in the ListView.

So you should use layout of the textview not the listview layout see here see here

    new ArrayAdapter<>(this, R.layout.layout_name_of_the_xml_containing_textview,R.id.rowTextView, array);

answered Mar 15, 2015 at 6:48

krishna

6098 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

droidchef · Accepted Answer · 2015-03-15 06:19:20Z

0

You must initialise your list in onCreate(), Just after the getSupportActionBar().setDisplayHomeAsUpEnabled(true);

And your ArrayAdapter<String> adapter should be a field not a local variable because, after you do array.add(result) you must also call adapter.notifyDataSetChanged() in order to refresh and populate the results in the listview

answered Mar 15, 2015 at 6:19

droidchef

2,3171 gold badge20 silver badges34 bronze badges

2 Comments

anu Over a year ago

didn't work. I made a Array Adapter a field variable and put adapter.notifyDataSetChanged() after array.add(result) and the app still crashed @Ishan Khanna

anu Over a year ago

it crashes saying: System services not available to Activities before onCreate() @ishan-khanna

Collectives™ on Stack Overflow

NULL POINTER EXCEPTION for arrayadapter in listview. ANDROID

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related