Error on opening database SQLite

Question

I'm using the following method to open my SQLite db.

private void open() {
    database = dbHelper.getReadableDatabase();
}

He's the relevent parts of dbHelper.

public void onCreate(SQLiteDatabase la_db) {
    String s;
    try {
        InputStream in = context.getResources().openRawResource(R.raw.sql);
        DocumentBuilder builder = DocumentBuilderFactory.newInstance()
                .newDocumentBuilder();
        Document doc = builder.parse(in, null);
        NodeList statements = doc.getElementsByTagName("statement");
        for (int i = 0; i < statements.getLength(); i++) {
            s = statements.item(i).getChildNodes().item(0).getNodeValue();
            la_db.execSQL(s);
        }
    } catch (Throwable t) {
        Toast.makeText(context, t.toString(), 50000).show();
    }
}

Part of sql.xml

....
<statement>
CREATE TABLE IF NOT EXISTS la_table (
    _id INTEGER PRIMARY KEY AUTOINCREMENT, 
    suggest_text_1 VARCHAR(100),
    test_value_1 VARCHAR(100),
    test_value_2 VARCHAR(100),
    test_type_1 VARCHAR(50),
    suggest_intent_data VARCHAR(5))
</statement>
<statement>INSERT INTO la_table VALUES(1,"Sodium (Na)","310 - 330 mg/dl",null,"Serum","1")</statement>
<statement>INSERT INTO la_table VALUES(2,"Potassium (K)","14 - 20 mg/dl","3.5 - 5 mmol/L or mEq/L","Serum","2")</statement>
.....

And I'm getting this error :

01-01 00:59:38.725: E/AndroidRuntime(2060): Caused by: java.lang.NullPointerException
01-01 00:59:38.725: E/AndroidRuntime(2060):     at com.assistant.lab.royale.DataSource.open(DataSource.java:42)
01-01 00:59:38.725: E/AndroidRuntime(2060):     at com.assistant.lab.royale.DataSource.listViewCursor(DataSource.java:25)
01-01 00:59:38.725: E/AndroidRuntime(2060):     at com.assistant.lab.royale.LabAssistant.onCreate(LabAssistant.java:24)
01-01 00:59:38.725: E/AndroidRuntime(2060):     at android.app.Activity.performCreate(Activity.java:4465)

@BorisStrandjev I initialize using private DatabaseHelper dbHelper;. — Binoy Babu
– Binoy Babu, Commented Mar 24, 2012 at 16:53
You did not show us the code which is mentioned in the stack frame — stefan bachert
– stefan bachert, Commented Mar 24, 2012 at 16:55
@binoy - no you are wrong. You declare it there. Can you please add the whole code of the class? — Boris Strandjev
– Boris Strandjev, Commented Mar 24, 2012 at 16:55
that's a delaration of the variable name and type only, add = new DatabaseHelper(); or do that later somewhere — zapl
– zapl, Commented Mar 24, 2012 at 16:55

Boris Strandjev · Accepted Answer · 2012-03-24 17:10:32Z

1

The code you provided will most definitely fail. You need to provide a context in the constructor of dbHelper. I suggest you change your class like that:

Add a constructor:

private DatabaseHelper dbHelper;
public DataSource(Context context) {
    this.dbHelper =  new DatabaseHelper(context);
}

You can not avoid passing in the context, but this usually is not a big problem, from every Activity you can just pass in this as the context. After this change you should be able to use your dbHelper without any problems.

answered Mar 24, 2012 at 17:10

Boris Strandjev

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Comments

zapl · Accepted Answer · 2012-03-24 16:53:50Z

1

dbHelper is null in your open(), you need to create an instance if your helper before you can use it.

answered Mar 24, 2012 at 16:53

zapl

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1 Comment

Binoy Babu Over a year ago

I tried adding private DatabaseHelper dbHelper = new DatabaseHelper(null);. It doesn't work stiil

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