Connection between my class and the Sqlite database

Question

I am trying to set the log in system on android using a username check between what the user inputs and what exists in the DB

Here is my piece of code, but it always gives me "invalid" and if i take the Try Catch block, it gives me a nullpointerException

public void checklogin(String logged){
    SQLiteDatabase db = null;
    DatabaseAdapter database = new DatabaseAdapter(this);       

        try{               
    Cursor mCursor = db.query(database.TABLE_USERS,new String[]{"select * from users"}, " Name like" + "'logged+'",null,null,null,null);

     if  (mCursor.moveToFirst()){
         Toast.makeText(LoginActivity.this, "Yaaaay", Toast.LENGTH_LONG).show();
     }}
        catch(NullPointerException e){
      Toast.makeText(LoginActivity.this, "invalid", Toast.LENGTH_LONG).show();

        }
        }

You nay want to assign db to a database before using it. – Kris Apr 22 '12 at 22:28 — Kris, Apr 22 '12 at 22:28

score 1 · Accepted Answer · answered Apr 22 '12 at 22:27

1

Well, you set db to be null... so when you call db.query it should rightfully give you a NullPointerException.

answered Apr 22 '12 at 22:27

Alex Lockwood

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I have corrected that by defining db in the beginning of the class.. but it still gives me "invalid" even if i enter a valid name. Is there any problem with the syntax of the cursor? – callback Apr 22 '12 at 22:41
You define `db` to be a local variable at the top of the method when you set `SQLiteDatabase db = null;`, so that is the reason why you are getting a `NullPointerException`. – Alex Lockwood Apr 22 '12 at 22:43
but yeah, there is also an issue with your syntax. see my edited post. – Alex Lockwood Apr 22 '12 at 22:45
Actually, just check this [link](http://stackoverflow.com/questions/1243199/sqlite-query-in-android-application). – Alex Lockwood Apr 22 '12 at 22:49

Connection between my class and the Sqlite database

1 Answers1