Um... Singleton.getInstance(Context) can call getApplicationContext on the Context that's passed in, without requiring the caller to do that.
20 декабря 2011 г. 21:57 пользователь Y2i <[email protected]> написал: >> No, Diane is saying that you can say >> Singleton.getInstance(context.getApplication()) to pass the >> Application reference to the singleton and it will be used to >> initialize the singleton if not already. > > No, Diane was clearly saying Singleton.getInstance(context) to pass context > (not the application) reference to the singleton (and it will be used to > initialize the singleton if not initialized already). And passing context > of random activities to initialize a singleton will result in the problems > described earlier. > > Consistently calling Singleton.getInstance(context.getApplicationContext()) > or Singleton.getInstance(context.getApplication()) will avoid memory leaks > and dead context problems, but the signature of > the Singleton.getInstance(Context) does not ensure that the method will > always be called with the application context as the parameter, which is not > the best choice from API design perspective. > > Having a method Singleton.getInstance(Application) instead > of Singleton.getInstance(Context) will ensure that no activity context will > be used to initialize the Singleton object. But from API design perspective > this method signature is not the best one because the actual parameter will > only be used once and ignored all other times. Using new > NormalObject(Application) instead of Singleton.getInstance(Application) is a > cleaner API. > >> >> Specifically, the case for me where Application.onCreate() is >> >> necessary is initializing singletons in this way. I have a lot of non- >> Android java code that hide the details of being run inside or outside >> of Android, and singletons are no exception. If running in Android, I >> want a version of my singleton to use a context. If not Android, a >> version with no context (something else). I need the >> Application.onCreate() entry point to establish this configuration for >> me or be forced to put that line of init code into every component's >> onCreate, which is horrible. > > This is exactly what I meant when I said "Application.onCreate() would be > the best place to initialize singletons that require a context" > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
