NullPointerException while retrieving data using Cursor

Question

I'm trying to retrieve some data from a table using a Cursor to display it in a TextView, but I'm getting an error.

Please care to help me.
Here's my code

public class DisplayBudget extends AppCompatActivity implements  View.OnClickListener {
  SQLiteDatabase db;
  TextView bname,name,limit;
  Button del;
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.budget_details);
    bname = (TextView) findViewById(R.id.textViewbname);
    name = (TextView) findViewById(R.id.textViewname);
    limit = (TextView) findViewById(R.id.textViewlimit);
    del = (Button) findViewById(R.id.button2);
    del.setOnClickListener(this);
    DBController dbController = new DBController(this);
    dbController.openToDisplay();
    Cursor cursor = db.rawQuery(" select *from "+DBHelper.TABLE_NAME+ " where id = 1 ",null);
    cursor.moveToFirst();
    name.append(cursor.getString(cursor.getColumnIndex(DBHelper.OWNER_NAME)));
    bname.append(cursor.getString(cursor.getColumnIndex(DBHelper.BUDGET_NAME)));
    limit.append(cursor.getString(cursor.getColumnIndex(DBHelper.BUDGET_LIMIT)));
    cursor.close();
}

Here's the LogCat

12-25 00:39:46.440  30123-30123/com.example.rajkumar.budget W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb0d40b20)
12-25 00:39:46.440  30123-30123/com.example.rajkumar.budget E/AndroidRuntime﹕    FATAL EXCEPTION: main
Process: com.example.rajkumar.budget, PID: 30123
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.rajkumar.budget/com.example.rajkumar.budget.DisplayBudget}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
        at android.app.ActivityThread.access$800(ActivityThread.java:135)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5001)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException
        at com.example.rajkumar.budget.DisplayBudget.onCreate(DisplayBudget.java:28)
        at android.app.Activity.performCreate(Activity.java:5231)

M D · Answer 1 · 2015-12-25T06:17:25.600

2

You got NPE because db=null at

 Cursor cursor = db.rawQuery(" select * from "+DBHelper.TABLE_NAME+ " where id = 1 ",null);

Where you initialized db ? also refer Nils Patel answer too for future problem.

edited Dec 25 '15 at 06:17

answered Dec 25 '15 at 06:02

M D

47,665
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@M D, yeah, but it won't initialize. i tried.. – RaJ Dec 25 '15 at 09:54
1

@RaJ You should learn first [How to play with SQLite in Android?](https://www.google.co.in/#q=sqliteopenhelper+in+android) – M D Dec 25 '15 at 09:58
yeah..thanks anyways – RaJ Dec 25 '15 at 10:15

score 1 · Answer 2 · answered Dec 25 '15 at 05:57

1

Take space between * and from so your query is look like,

Cursor cursor = db.rawQuery("select * from "+DBHelper.TABLE_NAME+ " where id = 1 ",null);

answered Dec 25 '15 at 05:57

Nils

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you got one issue and i got another one. – M D Dec 25 '15 at 06:03

score 0 · Answer 3 · answered Dec 25 '15 at 06:45

0

you just change that so u cant get error :-

String dataquery ="select * from table name where id =" +id;

Cursor cursor = db.rawQuery(dataquery,null);

its helpfull

answered Dec 25 '15 at 06:45

Kishan patel

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Quang Doan · Answer 4 · 2015-12-25T10:39:57.727

0

Try this.

DBController dbController = new DBController(this);
    SQLiteDatabase db = createDatabase.open();
 Cursor cursor = db.rawQuery(" select * from "+DBHelper.TABLE_NAME+ " where id = 1 ",null);
if(cursor.moveToFirst()){
 name.append(cursor.getString(cursor.getColumnIndex(DBHelper.OWNER_NAME)));
     bname.append(cursor.getString(cursor.getColumnIndex(DBHelper.BUDGET_NAME)));
    limit.append(cursor.getString(cursor.getColumnIndex(DBHelper.BUDGET_LIMIT)));     }

edited Dec 25 '15 at 10:39

answered Dec 25 '15 at 07:23

Quang Doan

632
4
12

you have to put space between * and from . as i mention above. – Nils Dec 25 '15 at 09:43
Yes, thank @Nils Patel – Quang Doan Dec 25 '15 at 09:45
you always welcome bro..!! – Nils Dec 25 '15 at 09:48
@Quang Doan, but it's not workin bro – RaJ Dec 25 '15 at 09:56
You cant show DBController.class – Quang Doan Dec 25 '15 at 10:39

NullPointerException while retrieving data using Cursor

4 Answers4