CODEWITHSUNDEEP
androidandroid-sqlite
Utman Alami
Utman Alami

Reputation: 131

insert in database with multiple activities

I have a problem, I created database for all activities, and in each activity I should insert information to database, so for the first activity , the insert is done , for the second activity I update the row with new insertion to complete all information and so on, my problem is that I don't know how to refer to the last row, I mean what should I do that make the update for the second activity occurs to the last row that has been insert in the first activity, do you have any suggestions ???

Upvotes: 0

Views: 1311

Answers (2)

Xaver Kapeller
Xaver Kapeller

Reputation: 49817

Well you can just use the primary key. When you insert something into the database you get as a return value the primary key. You can add this to the Intent that opens the other Activity and that way refer back to the row you previously inserted.

Edit:

I don't know if you are working with and SQLiteDatabase Object or with a ContentProvider, but in any case the code would be pretty much the same. In this example I will work directly with an SQLiteDatabase Object, even though using ContentProviders is in most cases the better alternative.

In your first Activity:

// When you perform an insert you get the id of the row which was just inserted.
long id = sqliteDatabase.insert("some_table", null, contentValues);

// The id will be -1 if an error occured
if(id >= 0) {
    ...
}

...

// When you start your second Activity you can add the id to the Intent 
Intent intent = new Intent(getApplicationContext(), SecondActivity.class);

// The String is a tag with which you can later retrieve the id from the Intent.
// Note that you should never hardcode String like that, use constants in your app.
intent.putExtra("rowId", id);

In the onCreate Method of your second Activity you can retrieve the id:

@Override
protected void onCreate (Bundle savedInstanceState) {
    // Check if the Activity has been created for the first time
    if(savedInstanceState == null) {

        // Retrieve the Intent with which the Activity was started
        Intent intent = getIntent();

        long id = intent.getLongExtra ("rowId", -1);

        // If id is valid proceed
        if(id >= 0) {
            Cursor cursor = sqliteDatabase.query("some_table", columns, "_id = ?", 
                                                 new String[] { String.valueOf(id) }, null, null, null, null);

            // Check if Cursor is valid and if yes read your data.
            if(cursor != null) {
                ...
            }           
        }
    }
}

Upvotes: 1

dandc87
dandc87

Reputation: 1106

The best way to do this would be to add a column to your database which will hold the time the row was inserted. Then when you need the latest row, query for the one with the most current time. An example SQL string would be:

SELECT * FROM my_table WHERE 1 ORDER BY time_stamp LIMIT 1

Upvotes: 0

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