NullPointerException with simpleAdapter in android

Question

I am using a simpleAdapter to create a listview, however I get this error:

Caused by: java.lang.NullPointerException
at com.tab.Activity.onCreate(Activity.java:36)

and this the code that I am using:

ArrayList<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>();
 private SimpleAdapter notes;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout);

    notes = new SimpleAdapter( 
            this, 
            list,
            R.layout.display_layout,
            new String[] { "line1" },
            new int[] { R.id.text1}  );
   ListView lv = (ListView) findViewById(R.id.listview);
   lv.setAdapter( notes );
}

line 36 would be

new int[] { R.id.text1}  );

text1 is defined, so why I am getting nullpointer error?

Are you sure this is the correct line? Could it be lv.setAdapter? Is R.id.listview defined? — kgiannakakis, Sep 20 '11 at 10:21
Stack trace and the layout file `display_layout.xml` might be helpful. — user802421, Sep 20 '11 at 10:34
R.id is always an int. Eclipse would give an error if it is otherwise. I am wondering does the class in which SimpleAdapter is used have to be extended from ListActivity only? — Kalimah, Sep 20 '11 at 11:37

score 0 · Answer 1 · answered Sep 20 '11 at 10:19

0

If the evaluation of

new int[] { R.id.text1 }

results in a NullPointerException it is due to the fact that R.id is null.

The exception would also arise if R.id happened to be an Integer which was null.

answered Sep 20 '11 at 10:19

aioobe

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I believe we can assume that **R.id.text1** is not **null** because it appears to be an **int**. It points to **R.id** being null. – John B Sep 20 '11 at 10:21
That's why I wrote from a "pure java perspective" (where `R.id.text1` could very well be an Integer). (Reformulated anyway) – aioobe Sep 20 '11 at 10:22
In Android context, it should be autogenerated int. – user802421 Sep 20 '11 at 10:35

score 0 · Answer 2 · answered Sep 20 '11 at 11:44

0

Try this:

    notes = new SimpleAdapter(this, list, R.layout.display_layout,
            new String[] { "line1" }, new int[] { android.R.id.text1 });

answered Sep 20 '11 at 11:44

Saqib Razaq

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Bitmap · Answer 3 · 2011-09-20T12:07:55.367

0

I think the value of R.id is returning null. Try:

new int[] { ((R.id !=null && R.id.text1 >-1)?R.id.text1 :-1)};

Edit

I am using -1 to assume zero could be an valid value.

edited Sep 20 '11 at 12:07

answered Sep 20 '11 at 12:02

Bitmap

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score 0 · Accepted Answer · answered Sep 21 '11 at 00:31

Finally, I solved the issue by implementing new SimpleAdapter following this tutorial: http://kurtchen.com/blog/2010/07/30/use-simpleadapter-to-make-a-list-with-icons/

I think the problem was that "ArrayList list" variable was null and therefore SimpleAdapter could not map any value to the "R.id.text1" column.

Thank you all for your answers

NullPointerException with simpleAdapter in android

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