Null pointer in fetching list view

Question

I am sorry in advance. I know this must be straight forward. Quite a novice with android. I am creating a main activity and trying to call another activity with the help of intent. Other activity contains a list view. I am trying to show simple strings in the list view. So I think that I don't need to write any of get view. Just AdapterView should work fine. Some code to explain more what I am upto is as follows : Main Activity button onClick method is as follows :

public void manage(View view) {
    Intent managerIntent;
           managerIntent = new Intent( this,ShowActivity.class);
    managerIntent.putExtra(FILE_URI, mediaStorageDir.getAbsolutePath());
    startActivity(managerIntent);
}

ShowActivity is as follows:

public class ShowActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ArrayList<String> strings = new ArrayList<String>();
        Intent intent = getIntent();
        MyService sc = new MyService()
        sc.fill(strings,intent);

        final ArrayAdapter<String> ListObject = new ArrayAdapter<String>(ShowReceiptsActivity.this,
                android.R.layout.simple_list_item_1, strings);

        ListView listView = (ListView)findViewById(R.id.listView);// This line gives null pointer exception
        listView.setAdapter(ListObject);
        setContentView(R.layout.activity_show_receipts);
    }
}

activity_show.xml is as follows:

<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.receiptboss.manager.ShowReceiptsActivity">

<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/listView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    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.receiptboss.manager.ShowReceiptsActivity"/>
</LinearLayout>

Any help is greatly appreciated.

Did you try ma solution? Did it resolve your issue?

Konrad Krakowiak
– Konrad Krakowiak

2015-02-07 21:35:09 +00:00
Commented Feb 7, 2015 at 21:35 — Konrad Krakowiak
– Konrad Krakowiak, Commented Feb 7, 2015 at 21:35

Konrad Krakowiak · Accepted Answer · 2015-02-07 20:53:49Z

1

You have to call setContentView(R.layout.activity_show) in onCreate(Bundle saveInstanceState) method in ShowActivity class as in code below:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //Here is your missing method
    // as param set R.layout.activity_show or R.layout.activity_show_receipts
    //it is depend of layout xml name 
    setContentView(R.layout.activity_show) 
    ....
}

You have to set your layout as content view in your activity, before you calling method findViewById(int) on your Activity. Now you're calling this method as last - it is wrong.

edited Feb 7, 2015 at 20:53

answered Feb 7, 2015 at 20:07

Konrad Krakowiak

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1 Comment

shaun Over a year ago

Thanks a lot. Its solved. I knew it should some stupid thing.

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