CODEWITHSUNDEEP
javaandroidlistviewnullpointerexception
emily
emily

Reputation: 467

Android nullpointerException - listview

I've seen other people who have had the same issue, but they were missing setContentView(). Any ideas as to why the below isn't working? NPE occurs when I call setAdapter because listView is null.

public class DisplayMessageActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setContentView(R.layout.activity_display_message);
ArrayList<String> message = getArray();

ListView listView = (ListView) findViewById(R.id.listView);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, message);

listView.setAdapter(adapter);

}; activity_main.xml

  <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"
android:orientation="horizontal"
tools:context=".MainActivity" >

  <EditText android:id="@+id/edit_message"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:hint="@string/edit_message" />

 <Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/button_send" 
    android:onClick="sendMessage" />


 <ListView android:id="@+id/listView"
          android:layout_height="match_parent"
          android:layout_width="match_parent"/>

 <TextView  
 android:id="@+id/rowTextView"   
 android:layout_width="fill_parent"   
 android:layout_height="wrap_content"  
 android:padding="10dp"  
 android:textSize="16sp" >  
</TextView>  


</LinearLayout>

Upvotes: 1

Views: 72

Answers (1)

FabianCook
FabianCook

Reputation: 20587

You are referencing R.layout.activity_display_message when you call setContentView meaning that (ListView) findViewById(R.id.listView); will return null

Instead of setContentView(R.layout.activity_display_message) call setContentView(R.layout.activity_main)

Upvotes: 2

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