Why does cursor.getString() line crash the app?

Question

The app crashes whenever it reaches the line where cursor.getString() is executed.

I've tried both cursor.getString() and cursor.getString(cursor.getColumnIndex(" ")) but it still crashed

The method it's executed on:

public void populateView(){
    Cursor data = myDb.getData();
    data.moveToFirst();
    String title = data.getString(data.getColumnIndex(1));
    newsList.add(new NewsItem(R.drawable.ic_home_black_24dp, title, "Description"));
    mAdapter = new NewsItemAdapter(newsList);
    mRecyclerView.setAdapter(mAdapter);
}

The method in DatabaseHelper class:

public Cursor getData(){
    SQLiteDatabase db = this.getReadableDatabase();
    String query = "SELECT * FROM " + TABLE_NAME_REPORT;
    Cursor data = db.rawQuery(query, null);

    data.close();
    db.close();

    return data;
}

P.S. The NewsItem class is accepting these arguments:

public NewsItem(int imageResource, String title, String desc){
    mImageResource = imageResource;
    mTitle = title;
    mDescription = desc;
}

Process: com.example.reportingapplication, PID: 32448
java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteQuery: SELECT * FROM report_data
    at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:55)
    at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:58)
    at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:151)
    at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:139)
    at android.database.AbstractCursor.moveToPosition(AbstractCursor.java:220)
    at android.database.AbstractCursor.moveToFirst(AbstractCursor.java:265)
    at com.example.reportingapplication.Fragments.HomeFragment.populateView(HomeFragment.java:104)
    at com.example.reportingapplication.Fragments.HomeFragment$1.onClick(HomeFragment.java:58)
    at android.view.View.performClick(View.java:6608)
    at android.view.View.performClickInternal(View.java:6585)
    at android.view.View.access$3100(View.java:785)
    at android.view.View$PerformClick.run(View.java:25921)
    at android.os.Handler.handleCallback(Handler.java:873)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:201)
    at android.app.ActivityThread.main(ActivityThread.java:6810)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)

What does "crash the app" mean? Please edit the question and post a full stack trace. There is no variable called "cursor" in your example. Post a [mcve]. — OldProgrammer, Jul 10 '19 at 13:25
Please include any error messages or stack traces. It's not always feasible to figure out what's going on just by looking at the code. However, in this case the problem _appears_ to be the fact that you're closing your cursor before you use it. From the [relevant docs](https://developer.android.com/reference/android/database/Cursor): "**close() -- Closes the Cursor, releasing all of its resources and making it completely invalid.**" — Jordan, Jul 10 '19 at 13:27
`java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteQuery: SELECT * FROM report_data` ← there's your problem, as @Jordan suspected. — Slaw, Jul 10 '19 at 13:30

score 0 · Accepted Answer · answered Jul 10 '19 at 13:38

0

Problem was closing the cursor before it was even used. Thanks to @Jordan who pointed it out in the comments.

answered Jul 10 '19 at 13:38

OJDylan

27
7

Why does cursor.getString() line crash the app?

1 Answers1