registering first date the app is launched

Question

I am developing an android app and I need to do something every month since the app is launched for the first time it is launched, the app will notify the user. how should i keep only the first date?

i used

  Calendar calendar = Calendar.getInstance();
    final int day = calendar.get(Calendar.DAY_OF_MONTH);
    final int month = calendar.get(Calendar.MONTH);
    Toast.makeText(getApplicationContext(), day + "\n" + month,
            Toast.LENGTH_LONG).show();

but it changes every time i run the app.

any better ideas?

Thanks

Answer 1

You can use the SharedPreferences. It will not allow you to store an Date object directly, but you can store a long which you can use for saving the date.getTime() value which represents the milliseconds since January 1, 1970, 00:00:00 GMT.

This is an example Activity that demonstrates this.

public class MyDateActivity extends Activity {
    public static final String PREFS_NAME = "MyPrefsFile";
    public static final String PREFS_LONG_DATE_FIRST_RUN = "FirstRun";

    private Date firstRunDate;

    @Override
    protected void onCreate(Bundle state){
        super.onCreate(state);

        // Restore preferences
        SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
        if (settings.contains(PREFS_LONG_DATE_FIRST_RUN)) {
            // Found date in settings
            long dateFirstRun = settings.getLong(PREFS_LONG_DATE_FIRST_RUN, 0);
            firstRunDate = new Date(dateFirstRun);
        } else {
            // First time running
            firstRunDate = new Date();
        }
    }

    @Override
    protected void onStop(){
        super.onStop();

        // Get preferences
        SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);

        // Only write the first run date if settings don't contain a first run date.
        if (!settings.contains(PREFS_LONG_DATE_FIRST_RUN)) {
            SharedPreferences.Editor editor = settings.edit();
            editor.putLong(PREFS_LONG_DATE_FIRST_RUN, new Date().getTime());
            editor.apply();
        }
    }
}