Unknown null pointer exception in Array Adapter

Question

I am getting a null pointer exception in the below line

ArrayAdapter<String> arrayadapt = new ArrayAdapter<String>(Loginpage.this,R.layout.activity_loginpage,R.id.textView1, numbers);

Here is the below code,

public class Loginpage extends Activity implements OnItemClickListener{

    TextView txtview;
    ListView listview;
    String[] numbers = {"987654321","456789321","451236987","4178522369"};

    Intent newInt;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_loginpage);
        txtview = (TextView)findViewById(R.id.textView1);
        listview = (ListView)findViewById(R.id.listView1);
        ArrayAdapter<String> arrayadapt = new ArrayAdapter<String>(Loginpage.this,R.layout.activity_loginpage,R.id.textView1, numbers);
        listview.setAdapter(arrayadapt);
        listview.setOnItemClickListener(this);


    }


    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

        String getdata = (String) parent.getItemAtPosition(position);

        newInt = new Intent(Intent.ACTION_DIAL);
        newInt.setData(Uri.parse("tel:"+getdata));
        startActivity(newInt);


    }


}

This is being called from an another activity, the call is from this line of code,

Intent yIntent = new Intent(this, Loginpage.class);
            startActivity(yIntent);

From Logcat

03-08 08:35:52.613: E/AndroidRuntime(2060): FATAL EXCEPTION: main
03-08 08:35:52.613: E/AndroidRuntime(2060): Process: com.example.androidex2, PID: 2060
03-08 08:35:52.613: E/AndroidRuntime(2060): java.lang.NullPointerException
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:392)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.AbsListView.obtainView(AbsListView.java:2255)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.ListView.measureHeightOfChildren(ListView.java:1263)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.ListView.onMeasure(ListView.java:1175)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.View.measure(View.java:16497)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1052)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:590)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.View.measure(View.java:16497)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.View.measure(View.java:16497)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.View.measure(View.java:16497)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.View.measure(View.java:16497)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1912)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1109)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1291)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.Choreographer.doCallbacks(Choreographer.java:574)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.Choreographer.doFrame(Choreographer.java:544)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.os.Handler.handleCallback(Handler.java:733)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.os.Handler.dispatchMessage(Handler.java:95)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.os.Looper.loop(Looper.java:136)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at android.app.ActivityThread.main(ActivityThread.java:5001)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at java.lang.reflect.Method.invokeNative(Native Method)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at java.lang.reflect.Method.invoke(Method.java:515)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
03-08 08:35:52.613: E/AndroidRuntime(2060):     at dalvik.system.NativeStart.main(Native Method)

R.layout.activity_loginpage

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.androidex2.Loginpage" >

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1" >

    </ListView>

</LinearLayout>

please provide your R.layout.activity_loginpage – yital9 Mar 08 '16 at 14:10 — yital9, Mar 08 '16 at 14:10

yital9 · Accepted Answer · 2016-03-08T14:52:29.453

1

You set into Adapter your main layout - R.layout.activity_loginpage

But as second parameter you have to pass a View, which will be used as "line" in ListView

So, create a new xml layout "listview_item.xml" with one TextView

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/textView1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

And call now

ArrayAdapter<String> arrayadapt = new ArrayAdapter<String>(Loginpage.this, R.layout.listview_item,R.id.textView1, numbers);

edited Mar 08 '16 at 14:52

answered Mar 08 '16 at 14:18

yital9

6,544
15
41
54

`R.id.textView1` is defined in a separate layout. Is it correct ? – oldcode Mar 08 '16 at 14:52
yes, and now you have to set this layout as second parameter into adapter. In my example its listview_item.xml – yital9 Mar 08 '16 at 14:54
Please tell me if I am correct or not. I have created a list view in a separate layout which is R.layout.activity_loginpage and a text view in a separate layout. – oldcode Mar 08 '16 at 14:55
yes, it's correct. You set your main layout R.layout.activity_loginpage as layout of the activity. It contains a ListView. And the listview_item.xml you have to use as a element/line of your ListView. It should be separated from your main layout and contain in your case only one TextView – yital9 Mar 08 '16 at 14:58

score 0 · Answer 2 · answered Mar 08 '16 at 14:20

0

You are passing the wrong layout to the adapter. It should be a layout for the row.

Javadoc The resource ID for a layout file containing a layout to use when instantiating views.

answered Mar 08 '16 at 14:20

user39950

464
3
15

score 0 · Answer 3 · answered Mar 08 '16 at 14:20

Don't pass R.layout.activity_loginpage to the constructor of the ArrayAdapter. The parameter on this place is for the layout to render a single item for the ArrayAdapter. The NullPointer occurs, as the R.layout.activity_loginpage layout you provide, does not contain a TextView with the id R.id.textView1.

To fix the issue, either create a separate layout that defines a TextView with the id R.id.textView1, or simply use one of the default layouts:

ArrayAdapter<String> arrayadapt = new ArrayAdapter<String>(Loginpage.this,android.R.layout.simple_list_item_1, R.id.textView1, numbers);

`R.id.textView1` is defined inside an another layout. – oldcode Mar 08 '16 at 14:25 — oldcode, Mar 08 '16 at 14:25

score 0 · Answer 4 · answered Mar 08 '16 at 14:27

0

You are not providing a text view with the id textView1. So, make a TextView with the id textView1 in your layout activity_loginpage.

answered Mar 08 '16 at 14:27

Chandan

187
1
8

it's wrong. in this case each ListView item will have the full layout (with ListView inside). You have to create a separate View only for a TextView – yital9 Mar 08 '16 at 14:47

Unknown null pointer exception in Array Adapter

4 Answers4