JavaNullPointerException/Layout Error when working with lists and ListView on Android
- by psyhclo
Hey, I'm trying to implement a ListView on Android, which will print the data retrieved from the SQLite Database. So I want to retrieve a lot of columns from the table and add this to a list, so I will print this list as a ListView.
For this I created a method that will select all the columns from the table in a separate class, and I will print the ListView in a ListActivity.
I want to retrieve 6 columns of the table, which is represented by the ids 2, 4, 5, 6, 7, 9.
But it shows a lot of errors:
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): FATAL EXCEPTION: main
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): java.lang.NullPointerException
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:355)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.ArrayAdapter.getView(ArrayAdapter.java:323)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.AbsListView.obtainView(AbsListView.java:1418)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.ListView.makeAndAddView(ListView.java:1745)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.ListView.fillDown(ListView.java:670)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.ListView.fillFromTop(ListView.java:727)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.ListView.layoutChildren(ListView.java:1598)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.AbsListView.onLayout(AbsListView.java:1248)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1254)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1130)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.LinearLayout.onLayout(LinearLayout.java:1047)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1254)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1130)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.LinearLayout.onLayout(LinearLayout.java:1047)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.View.layout(View.java:7175)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.ViewRoot.performTraversals(ViewRoot.java:1140)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.view.ViewRoot.handleMessage(ViewRoot.java:1859)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.os.Handler.dispatchMessage(Handler.java:99)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.os.Looper.loop(Looper.java:123)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at android.app.ActivityThread.main(ActivityThread.java:3647)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at java.lang.reflect.Method.invokeNative(Native Method)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at java.lang.reflect.Method.invoke(Method.java:507)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
12-24 19:19:04.066: ERROR/AndroidRuntime(22630): at dalvik.system.NativeStart.main(Native Method)
Here is the code of the method that select the data.
public List<String> selectAll() {
List<String> list1 = new ArrayList<String>();
List<String> list2 = new ArrayList<String>();
List<String> list3 = new ArrayList<String>();
List<String> list4 = new ArrayList<String>();
List<String> list5 = new ArrayList<String>();
List<String> list6 = new ArrayList<String>();
Cursor cursor = this.db.query(TABLE_NAME, null, null, null, null, null,
"duration desc");
if (cursor.moveToFirst()) {
do {
list1.add(cursor.getString(2));
list2.add(cursor.getString(4));
list3.add(cursor.getString(5));
list4.add(cursor.getString(6));
list5.add(cursor.getString(7));
list6.add(cursor.getString(9));
list1.addAll(list2);
list1.addAll(list3);
list1.addAll(list4);
list1.addAll(list5);
list1.addAll(list6);
} while (cursor.moveToNext());
Log.i(TAG, "After cursor.moveToNext()");
}
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}
Log.i(TAG, "Before selectAll returnment");
return list1;
}
And here is the code of the ListActivity class:
public class RatedCalls extends ListActivity {
private static final String LOG_TAG = "RatedCallsActivity";
private CallDataHelper cdh;
StringBuilder sb = new StringBuilder();
OpenHelper openHelper = new OpenHelper(RatedCalls.this);
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.i(LOG_TAG, "calling from onCreate()");
cdh = new CallDataHelper(this);
Log.i(LOG_TAG, "--->>> before calling the service");
startService(new Intent(this, RatedCallsService.class));
Log.i(LOG_TAG, "Service called.");
Log.i(LOG_TAG, "--->>> after calling the service");
fillList();
}
public void fillList() {
List<String> ratedCalls = this.cdh.selectAll();
setListAdapter(new ArrayAdapter<String>(this, R.layout.listitem,
ratedCalls));
ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// When clicked, show a toast with the TextView text
Toast.makeText(getApplicationContext(),
((TextView) view).getText(), Toast.LENGTH_SHORT).show();
}
});
}
}
