CODEWITHSUNDEEP
androidsqlite
Сергей Светлов
Сергей Светлов

Reputation: 81

Negative id value in SQLite Android

In the main activity I create database

class DBHelper extends SQLiteOpenHelper {

        public DBHelper(Context context) {

               super(context, "myDB", null, 1);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
          db.execSQL("create table mytable ("
                  + "id integer primary key autoincrement," 
                  + "name text," 
                  + "obId text," 
                  + "latit text,"
                  + "long text" + ");");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        }
      }

In the second activity I call the class of database

MainActivity myActivity = new MainActivity();
dbHelper = myActivity.new DBHelper(myActivity);

And insert data

ContentValues cv = new ContentValues();
db = openOrCreateDatabase("myDB.db", SQLiteDatabase.OPEN_READWRITE, null);
cv.put("name", textViewName.getText().toString());
long rowID = db.insert("mytable", null, cv);
db.insert("mytable", null, cv);
dbHelper.close();

The output "rowID" is "-1". I do not understand why this is happening

Upvotes: 1

Views: 1833

Answers (2)

laalto
laalto

Reputation: 152847

Use getWritableDatabase() on your database helper instead of openOrCreateDatabase() on a Context to get a database reference. You're operating on two different databases, out of which the other doesn't have the table you're attempting to insert to.

Also, you're inserting the same data twice.

If I use db = dbHelper.getWritableDatabase(); I will in Log java.lang.NullPointerException at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203) at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.ja‌​va:118) at com.ex.test.AddPoint.writePointsToDatabase(Add.java:264) at com.ex.test.AddPoint$3$2.onClick(Add.java:238)

That's because of you've passed in an invalid Context to the helper here:

MainActivity myActivity = new MainActivity();
dbHelper = myActivity.new DBHelper(myActivity);

You cannot instantiate activities with new. In an activity, use this to refer to a valid Context.

Upvotes: 1

user541747
user541747

Reputation: 73

You're operating on two different databases

That is "myDB" in

           super(context, "myDB", null, 1);

as opposed to "myDB.db" in 

db = openOrCreateDatabase("myDB.db", SQLiteDatabase.OPEN_READWRITE, null);

Best

Upvotes: 0

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