unable to create sqlite database in Android

Question

i have class CreateDB

public class CreateDB extends SQLiteOpenHelper{   // SQLiteOpenHelper auto create if db not exists.

    private static final int DB_VERSION = 1;
    private static final String DB_NAME = "mydb.db";

    public CreateDB(Context ctx) {
        super(ctx, DB_NAME, null, DB_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE friends (_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, phonenumber INTEGER);");
    }}

i call createdb in another class which act as background thread

public class manager extends AsyncTask<Void, Void, String> {

 public  Context context;

    @Override
    protected String doInBackground(Void... params) {

        CreateDB dbhelp = new CreateDB(context);
}

}

when i run it then it stop working and emulator give error that app stop responding

but when i run `CreateDB dbhelp = new CreateDB(this); in main activity then it works and database is created . so please help so that i can create database in background thread .

Alexis C. · Accepted Answer · 2013-10-26 10:05:27Z

2

but when i run CreateDB dbhelp = new CreateDB(this); in main activity then it works and database is created

Because you forgot to initialize your context object in your AsyncTask.

public class manager extends AsyncTask<Void, Void, String> {

 public  Context context; <-- Declared but not initialized

    @Override
    protected String doInBackground(Void... params) {

        CreateDB dbhelp = new CreateDB(context);
}

You could create a constructor for your AsyncTask :

public manager(Context context) {
   this.context = context;
}

And then in your activity :

new manager(this).execute();

Also try to respect name conventions.

edited Oct 26, 2013 at 10:05

answered Oct 26, 2013 at 10:00

Alexis C.

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2 Comments

user776046 Over a year ago

so how can i initialize Context context and with what

Alexis C. Over a year ago

When you're calling the asynctask in your activity, you can pass the activity itself as argument(with this), like I did in the constructor.

schabluk · Accepted Answer · 2013-10-26 10:01:08Z

0

You need to pass valid context as a parameter:

CreateDB dbhelp = new CreateDB(getContext());

answered Oct 26, 2013 at 10:01

schabluk

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