test123123 test123123 - 1 month ago 10
Android Question

NullPointerException in ListView

Hy!!

I have a listview that should be filled with data from the database

Code:

private void onCreateDBAndDBTabled() {
myDB = this.openOrCreateDatabase(MY_DB_NAME, MODE_PRIVATE, null);
myDB.execSQL("CREATE TABLE IF NOT EXISTS " + MY_DB_TABLE
+ " (_id integer primary key autoincrement, name varchar(100), rate integer(1), eattime datetime)"
+";");
ArrayList<Pizza> list = new ArrayList<Pizza>();
Cursor cursor = this.myDB.query(MY_DB_TABLE, new String[] { "name" },null,null,null,null,null,null);
if (cursor.moveToFirst()) {
do {
Log.e("XXX", "Courser Enter: " + cursor.getString(0));
Pizza pizza = new Pizza();
pizza.title= cursor.getString(0);
list.add(pizza);
}
while (cursor.moveToNext());
}
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}
Log.e("XXX", "Count:" + list.size());
Log.e("XXX", "Item[0] -->" + list.toArray()[0].toString());
CustomAdapter aa = new CustomAdapter(this, R.layout.customlistitem,list);
Log.e("XXX", String.valueOf(aa.getCount()));
lv.setAdapter(aa);
}


Customadapter:

public class CustomAdapter extends ArrayAdapter<Pizza>{

private ArrayList<Pizza> pizzen;

public CustomAdapter(Context context, int textViewResourceId,ArrayList<Pizza> objects) {
super(context, textViewResourceId, objects);
this.pizzen = objects;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
Pizza pizza = pizzen.get(position);
if (v == null) {

}

return v;//super.getView(position, convertView, parent);


}


Pizza:

public class Pizza{

public String title;
public int rate;
public Date date;
}


Error:

09-30 08:58:38.661: ERROR/XXX(667): Courser Enter: EditText
09-30 08:58:38.671: ERROR/XXX(667): Count:1
09-30 08:58:38.671: ERROR/XXX(667): Item[0] -->com.korn.pizzacounter.Pizza@43b91850
09-30 08:58:38.671: ERROR/XXX(667): 1
09-30 08:58:38.751: ERROR/AndroidRuntime(667): Uncaught handler: thread main exiting due to uncaught exception
09-30 08:58:38.762: ERROR/AndroidRuntime(667): java.lang.NullPointerException
09-30 08:58:38.762: ERROR/AndroidRuntime(667): at android.widget.AbsListView.obtainView(AbsListView.java:1276)
09-30 08:58:38.762: ERROR/AndroidRuntime(667): at android.widget.ListView.makeAndAddView(ListView.java:1668)
09-30 08:58:38.762: ERROR/AndroidRuntime(667): at android.widget.ListView.fillDown(ListView.java:637)
09-30 08:58:38.762: ERROR/AndroidRuntime(667): at android.widget.ListView.fillFromTop(ListView.java:694)
09-30 08:58:38.762: ERROR/AndroidRuntime(667): at android.widget.ListView.layoutChildren(ListView.java:1521)
09-30 08:58:38.762: ERROR/AndroidRuntime(667): at android.widget.AbsListView.onLayout(AbsListView.java:1113)
09-30 08:58:38.762: ERROR/AndroidRuntime(667): at android.view.View.layout(View.java:6830)


The error is a NullPoinerException although the ListSize is 1 (see the log)

Answer

It's because in your getView() method you are not inflating the convertView and it is returning you null.

Your getView should be something like this inflating a row.xml which contains a TextView.

@Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        TextView mTextView = null;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.row, parent, false);
            mTextView = (TextView) convertView.findViewById(R.id.txt_list);
            convertView.setTag(mTextView);
        }
        else{
            mTextView = (TextView) convertView.getTag();
        }
        mTextView.setText(arrList.get(position));
        return convertView;
    }