How to get my activity context

Question

I don t really get the idea behind how this whole thing works really  so if I have some class A that need the context of a class B which extends Activity  how do i get that context   I m searching for a more efficient way than giving the context as a parameter to class A constructor  For example if class A is going to have millions of instances then we would end up having millions of redundant pointer to Context while we should be able somehow to have just one somewhere and a getter function

User · Answer

Ok  I will give a small example on how to do what you ask  public class ClassB extends Activity     ClassA A1   new ClassA this      for activity context   ClassA A2   new ClassA getApplicationContext         for application context

User · Answer

you pass the context to class B in it s constructor  and make sure you pass getApplicationContext   instead of a activityContext

User · Answer

You can use Application class public class in android application package  that is           Base class for those who need to maintain global application state    You can provide your own implementation by specifying its name in your   AndroidManifest xml s  tag  which will cause that class   to be instantiated for you when the process for your   application package is created    To use this class do          public class App extends Application        private static Context mContext       public static Context getContext             return mContext             public static void setContext Context mContext            this mContext   mContext                      In your manifest          lt application         android icon               android label               android name  com example yourmainpackagename App   gt                         class that extends Application       In Activity B           public class B extends Activity        public void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout sampleactivitylayout            App setContext this                                           In class A                 Context c   App getContext      Note             There is normally no need to subclass Application  In most situation    static singletons can provide the same functionality in a more modular   way  If your singleton needs a global context  for example to register   broadcast receivers   the function to retrieve it can be given a   Context which internally uses Context getApplicationContext   when   first constructing the singleton

User · Answer

You can create a constructor using parameter Context of class A then you can use this context   Context c       A Context context   this c context    From B activity you create a object of class A using this constructor and passing getApplicationContext

User · Answer

In Kotlin will be     activity  applicationContext  let            it   lt - you context

User · Answer

If you need the context of A in B  you need to pass it to B  and you can do that by passing the Activity A as parameter as others suggested  I do not see much the problem of having the many instances of A having their own pointers to B  not sure if that would even be that much of an overhead    But if that is the problem  a possibility is to keep the pointer to A as a sort of global  avariable of the Application class  as  hasanghaforian suggested  In fact  depending on what do you need the context for  you could even use the context of the Application instead   I d suggest reading this article about context to better figure it out what context you need

User · Answer

The best and easy way to get the activity context is putting  this after the name of the Activity  For example  If your Activity s name is SecondActivity  its context will be SecondActivity this

[android] How to get my activity context?

Examples related to android

Examples related to android-context