通过后台活动传递数据

Question

I am working on database for a game.

I would like to get the score from one activity and call it in database activity, where it will be updated in the database by using intent, the game gets paused when intent is fired.

I have also tried using application class (suggestions on that are welcome).

Is there any way to pass data among activities by firing intent in background so that it does not interrupt the gameplay?

Answer 1

Your database should not be in an Activity. An Activity represents one screen (or one use-case) in your application, and should not represent implementation details like a database-class.

As an alternative, you can put your database code in a Singleton class that can be accessed from everywhere in the same application. You can also create the database in the Application's onCreate method and store it in a static field there or just create a separate class that exposes static methods to access the database.

If you are somehow dead-set on using Intents, you would need to use a database Service instead of an Activity. This way the current Activity will remain on top when you send the data to the service. But that would complicate things a lot compared to a simple static class/singleton approach.

Answer 2

You seem to have a big mix up: There shouldn't be a database activity . You should create a database helper class and make it a member variable in your application class.

// inside application class
private static MyDatabaseHelper mMyDB;

public MyDatabaseHelper static getDatabase() {
    if (mMyDB == null) {
        // mInstance should be the application instance, means make the
        // application class a singleton
        mMyDB = new MyDatabaseHelper(mInstance);
        // the constructor should open/create the database
    }
    return mMyDB;
}

With this you can work with your database from everywhere.

With that you can easily update every value from everywhere. So no need to fire an intent to pass values around. Instead just update your database directly.

Answer 3

There are multiple ways to this. You can use handlers, services, then use setresult which give call back to onactivity result of the parent activity.

Answer 4

Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
Bundle b = new Bundle();

b.putInt("key", 1);

intent.putExtras(b);

startActivity(intent);