Android SQLite Null Pointer Exception

I am getting this in LogCat:

05-20 17:16:34.721: E/AndroidRuntime(30461): FATAL EXCEPTION: main
05-20 17:16:34.721: E/AndroidRuntime(30461): java.lang.NullPointerException
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.database.sqlite.SQLiteStatement.releaseAndUnlock(SQLiteStatement.java:290)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:96)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.database.sqlite.SQLiteDatabase.updateWithOnConflict(SQLiteDatabase.java:1810)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.database.sqlite.SQLiteDatabase.update(SQLiteDatabase.java:1761)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at com.kickinglettuce.debtplannerpro.DebtDataSource.updateDebt(DebtDataSource.java:130)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at com.kickinglettuce.debtplannerpro.manageDebts$4.onClick(manageDebts.java:184)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.view.View.performClick(View.java:3511)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.view.View$PerformClick.run(View.java:14105)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.os.Handler.handleCallback(Handler.java:605)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.os.Looper.loop(Looper.java:137)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at android.app.ActivityThread.main(ActivityThread.java:4447)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at java.lang.reflect.Method.invokeNative(Native Method)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at java.lang.reflect.Method.invoke(Method.java:511)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-20 17:16:34.721: E/AndroidRuntime(30461):    at dalvik.system.NativeStart.main(Native Method)

Here is the code associated with it:

protected void onListItemClick(ListView l, View v, int position, long id) {

    List<Debt> values = datasource.getAllDebt();
            datasource.open();

    Debt item = values.get(position);
    final long boxId = item.getId();
    // final String BoxId = String.valueOf(boxId);
    final String BoxName = item.getName();
    final String BoxBalance = item.getBalance();
    final String BoxApr = item.getApr();
    final String BoxPayment = item.getPayment();

    // set up dialog
    final Dialog dialog = new Dialog(manageDebts.this);
    dialog.setContentView(R.layout.custom_dialog);
    dialog.setTitle("Edit Debt Details");
    dialog.setCancelable(true);

    // set up text
    TextView tv1 = (TextView) dialog.findViewById(R.id.textView1);
    TextView tv2 = (TextView) dialog.findViewById(R.id.textView2);
    TextView tv3 = (TextView) dialog.findViewById(R.id.textView3);
    TextView tv4 = (TextView) dialog.findViewById(R.id.textView4);
    EditText et1 = (EditText) dialog.findViewById(R.id.editText1);
    EditText et2 = (EditText) dialog.findViewById(R.id.editText2);
    EditText et3 = (EditText) dialog.findViewById(R.id.editText3);
    EditText et4 = (EditText) dialog.findViewById(R.id.editText4);

    tv1.setText("Debt Description");
    tv2.setText("Balance");
    tv3.setText("APR");
    tv4.setText("Monthly Payment");

    et1.setText(BoxName);
    et2.setText(BoxBalance);
    et3.setText(BoxApr);
    et4.setText(BoxPayment);

    // set up button
    Button button = (Button) dialog.findViewById(R.id.button1);
    button.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {


            datasource.updateDebt(Long.valueOf(boxId), BoxName, BoxBalance, BoxApr,
                    BoxPayment);
            dialog.dismiss();

        }
    });

    datasource.close();

    dialog.show();
}

And the Update Method in my database class:

public boolean updateDebt(long updateId, String debtName, String debtTotal,
        String debtApr, String paymentGoal) {

     ContentValues values = new ContentValues();
     values.put(MySQLiteHelper.COLUMN_DEBT_NAME, debtName);
     values.put(MySQLiteHelper.COLUMN_DEBT_TOTAL, debtTotal);
     values.put(MySQLiteHelper.COLUMN_APR, debtApr);
     values.put(MySQLiteHelper.COLUMN_PAYMENT, paymentGoal);
     String whereClause = MySQLiteHelper.COLUMN_ID + " = ?";
     String[] whereArgs = new String[]{ String.valueOf(updateId) };
     return database.update(MySQLiteHelper.TABLE_DEBT,
             values, whereClause, whereArgs) > 0;
}

Any suggestions?

Looks like your trying to access the db when it's been closed. Perhaps placing datasource.open() at the beginning of onCreate and datasource.close() at the end of onCreate() and calling them each just once in your class would solve your problem.

If you are editing, creating and deleting items in your activity requiring multiple calls to your database, consider calling datasource.open() at the beginning of a method that accesses the database and then close() at the end of of that method.

Miloš

The best is to use the SQLiteOpenHelper class which takes care for providing instance of SQLiteDatabase, it's singleton pattern:

see Android: java.lang.IllegalStateException: database xxx.db (conn# 0) already closed

来源：https://stackoverflow.com/questions/10678351/android-sqlite-null-pointer-exception

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android

sqlite

nullpointerexception