Call Fragment Function Over Activity

I have a TabLayout with 3 tab.They are a fragment. Test.java->PagerAdapter.java->TabFragment1+TabFragment2+TabFragment3 I want to call TabFragment1.helloworld() function. How

Solution 1:

You can access the desired fragment's method through your PagerAdapter:

((TabFragment1)adapter.getItem(0)).helloworld();

Solution 2:

It's a bit trickier than usual with ViewPagers, because you can't use the preferred findFragmentByTag() method. Here's something you could try - it's untested, but should be ok:

1. Create an interface, which all Fragments in your ViewPager implement:

   publicinterfaceViewPagerFragmentBase {
   
       voidcallCommonMethod(int code);
   
   }
   

2. Implement it in all your ViewPagerFragments:

   public FragmentOne implementsViewPagerFragmentBase {
   
       @OverridepublicvoidcallCommonMethod(int code) {
   
           if (code == 1) {
               //Run code in this Fragment
           }
   
       }
   
   public FragmentTwo implementsViewPagerFragmentBase {
   
       @OverridepublicvoidcallCommonMethod(int code) {
   
           if (code == 2) {
               //Run code in this Fragment
           }
   
       }
   

3. Inside your Activity class, grab all Fragments currently in your Adapter, then cycle through each one, calling the callCommonMethod() along with a code which indicates the Fragment you are trying to reach:

   publicclassMainActivityextendsAppCompatActivity {
   
       privatevoidcallCommonMethodInFragments(int code) {
   
           for (inti=0; i < viewPagerAdapter.getCount(); i++) {
               ((ViewPagerFragmentBase)viewPagerAdapter.getItem(i)).callCommonMethod(code);
           }
   
       }
   
       //To call it...
       callCommonMethodInFragments(1); //This will run the method in FragmentOne only
   
   }
   

If the code matches the one in the Fragment you are trying to reach, then the method will run.

Something else you could also try though is an EventBus - this would allow you to achieve your goal more directly, and with less typing: https://github.com/greenrobot/EventBus

Solution 3:

To call fragment method from parent activity:

ExampleFragmentfragment= (ExampleFragment) getFragmentManager().findFragmentById(R.id.example_fragment);
fragment.callFunction(); 

Solution 4:

I had the same issue, and this worked for me: You have to add the fragments via your adapter and then you can access the fragment functions:

    myViewPager = (ViewPager) findViewById(R.id.viewpager);
    MyAdapterClassadapter=newMyAdapterClass(getSupportFragmentManager());
    adapter.addFragment(newTabOneFragment(), "");
    adapter.addFragment(newTabTwoFragment(), "");
    adapter.addFragment(newTabThreeFragment(), "");
    myViewPager.setAdapter(adapter);

    myTabLayout = (TabLayout) findViewById(R.id.tab_layout);

    myTabLayout.setupWithViewPager(myViewPager);

    // to access fragment functions:TabOneFragmenttabOneFragment= (TabOneFragment) adapter.getItem(0);
    tabOneFragment.functionWhatSoEver();