How to properly close a cursor in android

Question

I have this database using sqlite, and I'm having problem with closing the cursor its saying that Application did not close the cursor or database object that was opened here here's the logcat

10-18 08:40:56.354: E/Cursor(331): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteCursor.<init>(SQLiteCursor.java:210)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:53)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1264)
10-18 08:40:56.354: E/Cursor(331):  at standard.internet.marketing.mymovingfriend.SQLHandler.checkMove(SQLHandler.java:1094)
10-18 08:40:56.354: E/Cursor(331):  at standard.internet.marketing.mymovingfriend.ListMovingNames$3.onKey(ListMovingNames.java:98)
10-18 08:40:56.354: E/Cursor(331):  at android.view.View.dispatchKeyEvent(View.java:3735)
10-18 08:40:56.354: E/Cursor(331):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 08:40:56.354: E/Cursor(331):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1667)
10-18 08:40:56.354: E/Cursor(331):  at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1102)
10-18 08:40:56.354: E/Cursor(331):  at android.app.Activity.dispatchKeyEvent(Activity.java:2063)
10-18 08:40:56.354: E/Cursor(331):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1643)
10-18 08:40:56.354: E/Cursor(331):  at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2471)
10-18 08:40:56.354: E/Cursor(331):  at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2441)
10-18 08:40:56.354: E/Cursor(331):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1735)
10-18 08:40:56.354: E/Cursor(331):  at android.os.Handler.dispatchMessage(Handler.java:99)
10-18 08:40:56.354: E/Cursor(331):  at android.os.Looper.loop(Looper.java:123)
10-18 08:40:56.354: E/Cursor(331):  at android.app.ActivityThread.main(ActivityThread.java:4627)
10-18 08:40:56.354: E/Cursor(331):  at java.lang.reflect.Method.invokeNative(Native Method)
10-18 08:40:56.354: E/Cursor(331):  at java.lang.reflect.Method.invoke(Method.java:521)
10-18 08:40:56.354: E/Cursor(331):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
10-18 08:40:56.354: E/Cursor(331):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
10-18 08:40:56.354: E/Cursor(331):  at dalvik.system.NativeStart.main(Native Method)

this issue's been bugging me for 3 days.

here some relevant code:

public class SQLHandler {

    public static final String KEY_MOVENAME = "movename";
    public static final String KEY_ID1 = "_id";
    public static final String KEY_ID5 = "_id";
    public static final String KEY_MOVEDATE = "movedate";
    public static final String KEY_TOTALMOVEWEIGHT = "totalmoveweight";
    public static final String KEY_TOTALITEM = "totalitem";

    private static final String DATABASE_NAME = "mymovingfriend";
    private static final int DATABASE_VERSION = 1;

    public static final String KEY_LISTITEMNAME = "listitemname";
    public static final String KEY_LISTITEMWEIGHT = "listitemweight";
    public static final String KEY_LISTITEMROOM = "listitemroom";

    private static final String DATABASE_TABLE1 = "movingname";
    private static final String DATABASE_TABLE5 = "listitem";

    public static final String CREATE_TABLE_1 = "CREATE TABLE " + DATABASE_TABLE1 + " (" + 
            KEY_ID1 + " INTEGER PRIMARY KEY AUTOINCREMENT," + 
            KEY_MOVEDATE + " TEXT NOT NULL, " + 
            KEY_TOTALMOVEWEIGHT + " TEXT NOT NULL, " + 
            KEY_TOTALITEM + " INTEGER NOT NULL, " +
            KEY_MOVENAME + " TEXT NOT NULL);";

    public static final String CREATE_TABLE_2 = "CREATE TABLE " + DATABASE_TABLE2 + " (" + 
            KEY_ID2 + " INTEGER PRIMARY KEY AUTOINCREMENT," + 
            KEY_ROOMMOVEHOLDER + " TEXT NOT NULL, " + 
            KEY_ROOMWEIGHT + " TEXT NOT NULL, " + 
            KEY_ROOM + " TEXT NOT NULL);";

    public static final String CREATE_TABLE_5 = "CREATE TABLE " + DATABASE_TABLE5 + " (" + 
            KEY_ID5 + " INTEGER PRIMARY KEY AUTOINCREMENT," + 
            KEY_LISTITEMNAME + " TEXT NOT NULL, " + 
            KEY_LISTITEMWEIGHT + " TEXT NOT NULL, " +
            KEY_LISTITEMROOM + " TEXT NOT NULL);";

    private DbHelper ourHelper;
    private final Context ourContext;
    private SQLiteDatabase ourDatabase;

    private static class DbHelper extends SQLiteOpenHelper{

        public DbHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub
            db.execSQL(CREATE_TABLE_1);
            db.execSQL(CREATE_TABLE_2);
            db.execSQL(CREATE_TABLE_3);
            db.execSQL(CREATE_TABLE_4);
            db.execSQL(CREATE_TABLE_5);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldversion, int newversion) {
            // TODO Auto-generated method stub
            db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE1);
            db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE2);
            db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE3);
            db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE4);
            db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE5);
            onCreate(db);
        }
    }

    public SQLHandler(Context c){
        ourContext = c;
    }

    public SQLHandler open() throws SQLException{
        ourHelper = new DbHelper(ourContext);
        ourDatabase = ourHelper.getWritableDatabase();
        return this;
    }

    public void close(){
        ourDatabase.close();
        ourHelper.close();
    }

    public long createMove(String smovename){
        ContentValues cv = new ContentValues();
        cv.put(KEY_MOVENAME, smovename);
        cv.put(KEY_MOVEDATE, "Not yet set");
        cv.put(KEY_TOTALMOVEWEIGHT, "0");
        cv.put(KEY_TOTALITEM, 0);
        return ourDatabase.insert(DATABASE_TABLE1, null, cv);
    }

    public void createList(){

        String[] sroom = new String[]{"Kitchen", "Bedroom", "Dinning Room"};
        String[] sitem = new String[]{"Dishwasher", "Bed", "Table"};
        String[] sweight = new String[]{"40", "25", "15"};

        for (int i = 0; i < sroom.length; i++) {
            cv.put(KEY_LISTITEMROOM, sroom[i]);
            cv.put(KEY_LISTITEMNAME, sitem[i]);
            cv.put(KEY_LISTITEMWEIGHT, sweight[i]);
            ourDatabase.insert(DATABASE_TABLE5, null, cv);
        }
    }

    public void setMoveDate(String smovedate, String smovename){
        ContentValues cv = new ContentValues();
        cv.put(KEY_MOVEDATE, smovedate);
        ourDatabase.update(DATABASE_TABLE1, cv, KEY_MOVENAME + "='" + smovename + "'", null);
    }

    public void setMoveWeight(String smoveweight, String smovename){
        ContentValues cv = new ContentValues();
        cv.put(KEY_TOTALMOVEWEIGHT, smoveweight);
        ourDatabase.update(DATABASE_TABLE1, cv, KEY_MOVENAME + "='" + smovename + "'", null);
    }

    public void setTotalItem(String smovename, int imoveitem){
        ContentValues cv = new ContentValues();
        cv.put(KEY_TOTALITEM, imoveitem);
        ourDatabase.update(DATABASE_TABLE1, cv, KEY_MOVENAME + "='" + smovename + "'", null);
    }

    public void renameRoom(String movename, String roomname, String currentroom){
        ContentValues cv = new ContentValues();
        cv.put(KEY_ROOM, roomname);
        ourDatabase.update(DATABASE_TABLE2, cv, KEY_ROOMMOVEHOLDER + "='" + movename + "'" + " AND " + KEY_ROOM + "='" + currentroom + "'", null);
    }

    public void setRoomWeight(String sroomweight, String smovename, String sroomname){
        ContentValues cv = new ContentValues();
        cv.put(KEY_ROOMWEIGHT, sroomweight);
        ourDatabase.update(DATABASE_TABLE2, cv, KEY_ROOMMOVEHOLDER + "='" + smovename + "'" + " AND " + KEY_ROOM + "='" + sroomname + "'", null);
    }

    public long addRooms(String sroommoveholder, String sroom){
        ContentValues cv = new ContentValues();
        cv.put(KEY_ROOMMOVEHOLDER, sroommoveholder);
        cv.put(KEY_ROOM, sroom);
        cv.put(KEY_ROOMWEIGHT, "0");
        return ourDatabase.insert(DATABASE_TABLE2, null, cv);
    }

    public long addNewItems(String sitemmoveholder, String sroomholder, String sitemname, String sitemvalue, String sitemweight){
        ContentValues cv = new ContentValues();
        cv.put(KEY_ITEMMOVEHOLDER, sitemmoveholder);
        cv.put(KEY_ROOMHOLDER, sroomholder);
        cv.put(KEY_ITEMNAME, sitemname);
        cv.put(KEY_ITEMVALUE, sitemvalue);
        cv.put(KEY_ITEMWEIGHT, sitemweight);
        return ourDatabase.insert(DATABASE_TABLE3, null, cv);
    }

    public void updateItems(String sitemmoveholder, String sroomholder, String sitemname, String sitemvalue, String sitemweight){
        ContentValues cv = new ContentValues();
        cv.put(KEY_ITEMVALUE, sitemvalue);
        cv.put(KEY_ITEMWEIGHT, sitemweight);
        ourDatabase.update(DATABASE_TABLE3, cv, KEY_ITEMMOVEHOLDER + "='" + sitemmoveholder + "'" + " AND " + 
                KEY_ROOMHOLDER + "='" + sroomholder + "'" + " AND " + KEY_ITEMNAME + "='" + sitemname + "'", null);
    }

    public Cursor getMove(){
        String[] columns = new String[]{KEY_ID1, KEY_MOVENAME};

        Cursor c = null;
        try {
            c = ourDatabase.query(DATABASE_TABLE1, columns, null, null, null, null, null);
        } catch (Exception e) {
            c.close();
        }
        return c;
    }

    public String getTotalWeight(String m) throws SQLException{
        String[] columns = new String[]{KEY_ID1, KEY_MOVENAME, KEY_MOVEDATE, KEY_TOTALMOVEWEIGHT};

        Cursor c = null;
        try {
            c = ourDatabase.query(DATABASE_TABLE1, columns, KEY_MOVENAME + "= '" + m + "'", null, null, null, null);
            if (c != null) {
                c.moveToFirst();
                String totalWeight = c.getString(3);
                return totalWeight;
            }
        } catch (Exception e) {
            c.close();
        }
        return null;

    }

    public String getTotalWeightLBS(String m) throws SQLException{
        String[] columns = new String[]{KEY_ID1, KEY_MOVENAME, KEY_MOVEDATE, KEY_TOTALMOVEWEIGHT};

        Cursor c = null;
        try {
            c = ourDatabase.query(DATABASE_TABLE1, columns, KEY_MOVENAME + "= '" + m + "'", null, null, null, null);
            if (c != null) {
                c.moveToFirst();
                int x = Integer.parseInt(c.getString(3)) * 7;
                String totalWeight = "" + x + " lbs";
                return totalWeight;
            }
        } catch (Exception e) {
            c.close();
        }
        return null;

    }

    public String getDateMove(String md){
        String[] columns = new String[]{KEY_ID1, KEY_MOVENAME, KEY_MOVEDATE};

        Cursor c = null;try {
            c = ourDatabase.query(DATABASE_TABLE1, columns, KEY_MOVENAME + "= '" + md + "'", null, null, null, null);

            if (c != null) {
                c.moveToFirst();
                String moveDate = c.getString(2);
                return moveDate;
            }
        } catch (Exception e) {
            c.close();
        }
        return null;
    }

    public ArrayList<String> loadRooms(String mn) throws SQLException{
        String[] columns = new String[]{KEY_ID2, KEY_ROOMMOVEHOLDER, KEY_ROOM};

        ArrayList<String> array = new ArrayList<String>();

        Cursor c = null;
        try {
            c = ourDatabase.query(DATABASE_TABLE2, columns,KEY_ROOMMOVEHOLDER + "='" + mn + "'", 
                    null, null, null, null);
            int iroom = c.getColumnIndex(KEY_ROOM);

            for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
                array.add(c.getString(iroom));
            }
        } catch (Exception e) {
            c.close();
        }
        return array;
    }

    public void deleteMove(String m) throws SQLException{
        ourDatabase.delete(DATABASE_TABLE1, KEY_MOVENAME + "='" + m + "'", null);
        ourDatabase.delete(DATABASE_TABLE2, KEY_ROOMMOVEHOLDER + "='" + m + "'", null);
        ourDatabase.delete(DATABASE_TABLE3, KEY_ITEMMOVEHOLDER + "='" + m + "'", null);
        ourDatabase.delete(DATABASE_TABLE4, KEY_TODOMOVE + "='" + m + "'", null);
    }

    public ArrayList<String> getitems(){
        String[] columns = new String[]{KEY_ID5, KEY_ITEMNAME};
        ArrayList<String> items;
        items = new ArrayList<String>();

        Cursor c = null;
        try {
            c = ourDatabase.query(DATABASE_TABLE5, columns, null, null, null, null, null);

            for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
                items.add(c.getString(1));
            }
        } catch (Exception e) {
            c.close();
        }

        return items;
    }

    public ArrayList<String> getitemweight(){
        String[] columns = new String[]{KEY_ID5, KEY_ITEMWEIGHT};
        ArrayList<String> items = new ArrayList<String>();

        Cursor c = null;
        try {
            c = ourDatabase.query(DATABASE_TABLE5, columns, null, null, null, null, null);
            for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
                items.add(c.getString(1));
            }
        } catch (Exception e) {
            c.close();
        }

        return items;
    }

    public ArrayList<String> getitemclass(){
        String[] columns = new String[]{KEY_ID5, KEY_LISTITEMROOM};
        ArrayList<String> items = new ArrayList<String>();

        Cursor c = null;
        try {
            c = ourDatabase.query(DATABASE_TABLE5, columns, null, null, null, null, null);

            for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
                items.add(c.getString(1));
            }
        } catch (Exception e) {
            c.close();
        }

        return items;
    }

}

pawelzieba · Accepted Answer · 2012-10-18T14:29:43.203

26

You're not closing cursor in getDateMove, getTotalWeightLBS, loadRooms,...

Everywhere where cursor is not needed anymore close it. In those methods use try-finally, it will guarantee to execute code in finally block even when thrown exception occur.

Change code in your methods from this:

try{
  // get data from cursor
} catch (Exception e) {
    c.close();
}

to this:

try {
   // get data from cursor
} catch (Exception e) {
   // exception handling
} finally {
   if(c != null){
       c.close();
   }
}

edited Oct 18 '12 at 14:29

answered Oct 18 '12 at 09:01

pawelzieba

16,082
3
46
72

wait i made a typo, fix it just a sec – philip Oct 18 '12 at 09:18
The exception was thrown from `checkMove` method which is not included in your code. – pawelzieba Oct 18 '12 at 14:25
1

If you've finished reading from Cursor, close it - that's all. – pawelzieba Oct 18 '12 at 14:27

Paul Woitaschek · Answer 2 · 2016-07-27T13:01:20.147

11

If an element is implementing AutoCloseable (like the Cursor.class does), I would recommend to do a try-with-resources, like described here. If you use Retrolambda it has the try-with-resources backported.

So your code:

Cursor cursor = db.query("tableName", columns, null, null, null, null, null);
try {
    if (cursor.moveToFirst()) return cursor.getString(3);
    else return null;
} finally {
   cursor.close();
}

would simply turn into:

try (Cursor cursor = db.query("tableName", columns, null, null, null, null, null)) {
    if (cursor.moveToFirst()) return cursor.getString(3);
    else return null;
}

edited Jul 27 '16 at 13:01

answered Dec 11 '14 at 14:17

Paul Woitaschek

6,717
5
33
52

1

As a note, this method requires API 19 – Jonathan Muller Feb 24 '15 at 15:07
1

Im using it with API 11, and never received a crash while having about 3k users the last months. – Paul Woitaschek Feb 24 '15 at 15:14
Android Studio's inspector highlights the try in red with "Try-with-resources requires API level 19 (current min is 15)", however I tested and it compiles and runs fine on a phone API level 17. Apparently it's not supposed to be supported on minAPI<19. http://stackoverflow.com/questions/20480090/does-android-support-jdk-6-or-7/22303654#22303654 While it might work on some devices, it should NOT be recommended. – Murphy Jul 01 '16 at 07:53
why to open cursor inside of try block ? – Malachiasz Jul 27 '16 at 08:46
@Malachiasz Because its a good practice to minimize the scope of local variables (Effective Java item #45). Also delegating the cursor closing is a good idea as its less error prone and you can't forget to call `.close`. – Paul Woitaschek Jul 27 '16 at 08:53
@PaulWoitaschek: I have actually meant the 1st version, because the 2nd is not available under older Android OS versions. So the scope of variable is not smaller there, because declaration of variable happens before try block. If I close cursor in finally then I won't forget about closing. Only problem would be if somebody added some code between getting cursor from the DB and starting try - finally block. – Malachiasz Jul 27 '16 at 09:31
@Malachiasz You're absolutely right about the first version. I just simplified it. Btw, retrolambda backported try-with-resources so you can use it in earlier versions of android too. – Paul Woitaschek Jul 27 '16 at 13:03

score 9 · Answer 3 · answered Oct 18 '12 at 08:58

9

Closing cursor in finally will guarantee it will be closed;

public void myfunc() {

    Cursor c = null;

    try {

      c = ... // Open cursor here
      return .... // maybe return something

    } finally {
       if(c != null) { c.close(); }
    } 
}

answered Oct 18 '12 at 08:58

Alexander Kulyakhtin

47,782
38
107
158

why to open cursor inside of try block ? – Malachiasz Jul 27 '16 at 08:46
try-with-resources is much more elegant – mbonness May 24 '18 at 21:33

score 8 · Answer 4 · answered Aug 19 '19 at 20:29

If you use Kotlin (also available in Java in a bit different way), and Android 4.1 and above, you can use this:

    cursor?.use { 
       //..do stuff
    }

As an example, you can check here.

If you want to use Java, do something like:

        try (Cursor cursor = ...) {
            // do something
        }

score 0 · Answer 5 · answered Oct 18 '12 at 08:59

0

close your database in onStop() or onDestroy() method of your activity!

answered Oct 18 '12 at 08:59

Ashwani

1,574
14
28

score 0 · Answer 6 · answered Oct 18 '12 at 09:01

0

You are trying to close cursor inside catch block using

catch (Exception e) {
            c.close();
        }

But if you did not get any exception then how it will close

so put it inside the finally block

finally {
            c.close();
        }

answered Oct 18 '12 at 09:01

subodh

6,136
12
51
73

oh, then try to call `startManagingCursor()` after you get the Cursor from your query. – subodh Oct 18 '12 at 09:18
already did that, the cursor that's been giving an error seams to be from the database and not the cursor from the activity – philip Oct 18 '12 at 09:22

vinothp · Answer 7 · 2012-10-18T09:18:43.557

-3

Try this,

In onStop() or onDestroy()

Check whether the cursor is null

@Override
public void onStop(){
 Cursor cursor;

 if(cursor!=null){
  cursor.close();}
 }

If not then close the cursor.

EDIT

To Close the database object

DatabaseObject db;
if(db!=null)
{ db.close();}

Hope it helps.

edited Oct 18 '12 at 09:18

answered Oct 18 '12 at 09:05

vinothp

9,939
19
61
103

Oh i see. Try closing you database object as well – vinothp Oct 18 '12 at 09:13

How to properly close a cursor in android

7 Answers7

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