Call an activity method from a fragment

Question

Trying to call a method in my activity from a fragment  I want the fragment to give the method data and to get the data when the method return  I want to achieve similar to call on a static method  but without the use of static because it create problems in the activity    New to fragments so I need an easy and pedagogic explanation   Thanks

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Thanks  BIJAY JHA and  Manaus  I used the Kotlin version to call my signIn   method that lives in the Activity and that I m calling from a Fragment  I m using Navigation Architecture in Android so the Listener interface pattern isn t in the Fragment    activity as MainActivity  signIn

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From fragment to activty     YourActivityClassName getActivity    yourPublicMethod      From activity to fragment   FragmentManager fm   getSupportFragmentManager       if you added fragment via layout xml YourFragmentClass fragment    YourFragmentClass fm findFragmentById R id your fragment id   fragment yourPublicMethod      If you added fragment via code and used a tag string when you added your fragment  use findFragmentByTag instead   YourFragmentClass fragment    YourFragmentClass fm findFragmentByTag  yourTag

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For Kotlin try it out  class DataForm   Fragment         override fun onViewCreated view  View  savedInstanceState  Bundle             Tasks this  getData              fun getResponse response  String               code          class Tasks private val context  Any        fun getData              val getContext    context as DataForm  activity         val getFragment    context as DataForm           val responseListener   Response Listener lt String gt    response - gt              getFragment getResponse response                     val errorListener   Response ErrorListener   error - gt              error printStackTrace                       val stringRequest   StringRequest Request Method GET  url  responseListener  errorListener          Volley newRequestQueue getContext  add stringRequest

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I have tried with all the methods shown in this thread and none worked for me  try this one  It worked for me     MainActivity  getContext   getApplicationContext    Method

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For Kotlin developers   activity as YourActivityClassName  methodName     For Java developers    YourActivityClassName  getActivity    methodName

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Although i completely like Marco s Answer i think it is  fair to point out that you can also use a publish subscribe based framework to achieve the same result for example if you go with the event bus you can do the following   fragment      EventBus getDefault   post new DoSomeActionEvent        Activity     Subscribe onSomeActionEventRecieved DoSomeActionEvent doSomeActionEvent     Do something

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Here is how I did this  first make interface interface NavigationInterface       fun closeActivity      next make sure activity implements interface and overrides interface method s  class NotesActivity   AppCompatActivity    NavigationInterface        override fun onCreate savedInstanceState  Bundle             super onCreate savedInstanceState          setContentView R layout activity notes          setSupportActionBar findViewById R id toolbar              override fun closeActivity             this finish            then make sure to create interface listener in fragment private lateinit var navigationInterface  NavigationInterface  override fun onCreateView          inflater  LayoutInflater  container  ViewGroup           savedInstanceState  Bundle     View          establish interface communication     activity  let           instantiateNavigationInterface it               Inflate the layout for this fragment     return inflater inflate R layout fragment notes info  container  false     private fun instantiateNavigationInterface context  FragmentActivity        navigationInterface   context as NavigationInterface    then you can make calls like such  view findViewById lt Button gt  R id button second  setOnClickListener       navigationInterface closeActivity

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YourActivityName getActivity    functionName     Example     SessionActivity getActivity    changeFragment     Note   class name should be in public

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I have been looking for the best way to do that since not every method we want to call is located in Fragment with same Activity Parent   In your Fragment  public void methodExemple View view               your code here          Toast makeText view getContext     Clicked clicked  Toast LENGTH LONG  show            In your Activity  new ExempleFragment   methodExemple context

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You should probably try to decouple the fragment from the activity in case you want to use it somewhere else  You can do this by creating a interface that your activity implements    So you would define an interface like the following   Suppose for example you wanted to give the activity a String and have it return a Integer   public interface MyStringListener      public Integer computeSomething String myString       This can be defined in the fragment or a separate file    Then you would have your activity implement the interface    public class MyActivity extends FragmentActivity implements MyStringListener      Override   public Integer computeSomething String myString          Do something with the string and return your Integer instead of 0         return 0           Then in your fragment you would have a MyStringListener variable and you would set the listener in fragment onAttach Activity activity  method    public class MyFragment            private MyStringListener listener            Override         public void onAttach Context context                super onAttach context               try                   listener    MyStringListener  context                catch  ClassCastException castException                        The activity does not implement the listener                                      edit 17 12 2015  onAttach Activity activity  is deprecated  use onAttach Context context  instead  it works as intended  The first answer definitely works but it couples your current fragment with the host activity  Its good practice to keep the fragment decoupled from the host activity in case you want to use it in another acitivity

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In kotlin you can call activity method from fragment like below   var mainActivity  MainActivity   activity as MainActivity         mainActivity showToast     Calling show toast method of activity

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your activity  getActivity  method name     Where your activity is the name of your activity and method name   is the name of the method you want to call

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This is From Fragment class       KidsStoryDashboard getActivity    values title txt bannerImgUrl     This Code From Activity Class      public void values String title txts  String bannerImgUrl        if   title txts isEmpty         Do something to set text            imageLoader displayImage bannerImgUrl  htab header image  doption

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Update after I understand more how fragments work  Each fragment belongs to a parent activity  So just use   getActivity   whatever   From within the fragment  It is a better answer because you avoid superflous casts  If you cannot avoid the casts with this solution use the one below                 what you have to do is to cast to the outer activity     MainActivity  getActivity    Method      creating a new instance will be confusing the android frame and it will not be able to recognize it   see also     https   stackoverflow com a 12014834 1984636  https   stackoverflow com a 2042829 1984636

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For accessing a function declared in your Activity via your fragment please use an interface  as shown in the answer by marco   For accessing a function declared in your Fragment via your activity you can use this if you don t have a tag or an id  private void setupViewPager ViewPager viewPager          fragmentOne fragmentTwo and fragmentThree are all global variables     fragmentOne  new FragmentOne        fragmentTwo  new FragmentTwo        fragmentThree   new FragmentThree         viewPagerAdapteradapter   new ViewPagerAdapter getSupportFragmentManager         viewPagerAdapteradapter addFragment fragmentOne   Frag1        viewPagerAdapteradapter addFragment fragmentTwo   Frag2        viewPagerAdapteradapter addFragment fragmentThree   Frag3           viewPager has to be instantiated when you create the activity        ViewPager viewPager    ViewPager findViewById R id pager         setupViewPager viewPager         Where R id pager is the id of the viewPager defined in your activity s xml page       viewPager setAdapter viewPagerAdapteradapter           frag1 and frag2 are also global variables     frag1    FragmentOne viewPagerAdapteradapter mFragmentList get 0       frag2    FragmentTwo viewPagerAdapteradapter mFragmentList get 1            You can use the variable fragmentOne or frag1 to access functions declared in FragmentOne       This is the ViewpagerAdapterClass      class ViewPagerAdapter extends FragmentPagerAdapter       public final List lt Fragment gt  mFragmentList   new ArrayList lt  gt         private final List lt String gt  mFragmentTitleList   new ArrayList lt  gt          public ViewPagerAdapter FragmentManager manager            super manager               Override     public Fragment getItem int position            return mFragmentList get position               Override     public int getCount             return mFragmentList size               public void addFragment Fragment fragment  String title            mFragmentList add fragment           mFragmentTitleList add title               Override     public CharSequence getPageTitle int position            return mFragmentTitleList get position             This answer is for noobs like me  Have a good day

[android] Call an activity method from a fragment

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