I've been trying to retrieve the data from a preloaded database and I always getting an error of a NullPointerException. I'm trying to retrieve the data to a listview. I don't know the what the problem is. Please help me. Thanks.
public class Retrieve extends Activity {
Dbhelper dbhelper;
protected ListAdapter adapter;
SQLiteDatabase db;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.ret_all_info);
String[] from = new String[] { "_id" };
int[] to = new int[] { R.id.studid};
dbhelper = new Dbhelper(this);
try {
dbhelper.createDataBase();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Cursor c = dbhelper.getData();
adapter = new SimpleCursorAdapter(getApplicationContext(), R.layout.ret_all, c, from, to, 0);
ListView list = (ListView) findViewById(R.id.ListView1);
list.setAdapter(adapter);
list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// TODO Auto-generated method stub
Intent intent = new Intent(Retrieve.this, RetrieveDetails.class);
Cursor cursor = (Cursor) adapter.getItem(position);
intent.putExtra("COMMAND_ID", cursor.getInt(cursor.getColumnIndex("_id")));
startActivity(intent);
}
});
}
}
Here is the Logcat
02-13 21:05:11.402: E/Trace(22808): error opening trace file: No such file or directory (2)
02-13 21:05:11.572: E/dalvikvm(22808): GC_CONCURRENT freed 314K, 9% free 6590K/7239K, paused 2ms+12ms, total 28ms
02-13 21:05:22.832: E/Trace(22895): error opening trace file: No such file or directory (2)
02-13 21:05:22.972: E/dalvikvm(22895): GC_CONCURRENT freed 305K, 10% free 6577K/7239K, paused 13ms+3ms, total 37ms
02-13 21:05:23.192: E/AndroidRuntime(22895): FATAL EXCEPTION: main
02-13 21:05:23.192: E/AndroidRuntime(22895): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.tutsiroll/com.example.tutsiroll.Retrieve}: java.lang.NullPointerException
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.app.ActivityThread.access$600(ActivityThread.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.app.ActivityThread$H.handleMessage(ActivityThread.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.os.Handler.dispatchMessage(Handler.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.os.Looper.loop(Looper.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.app.ActivityThread.main(ActivityThread.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at java.lang.reflect.Method.invokeNative(Native Method)
02-13 21:05:23.192: E/AndroidRuntime(22895): at java.lang.reflect.Method.invoke(Method.java:511)
02-13 21:05:23.192: E/AndroidRuntime(22895): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at dalvik.system.NativeStart.main(Native Method)
02-13 21:05:23.192: E/AndroidRuntime(22895): Caused by: java.lang.NullPointerException
02-13 21:05:23.192: E/AndroidRuntime(22895): at com.example.tutsiroll.Retrieve.onCreate(Retrieve.java:43)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.app.Activity.performCreate(Activity.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java)
02-13 21:05:23.192: E/AndroidRuntime(22895): at com.lbe.security.service.core.client.b.x.callActivityOnCreate(Unknown Source)
02-13 21:05:23.192: E/AndroidRuntime(22895): ... 12 more
