android - Passing data back to previous fragment from current fragment

Question

I am Using Navigation Drawer in my app. I have one MainActivity and rest of are Fragments. So the issue is Suppose i have three fragments like A,B,C.

Now in A i have one button and i am sending data from A>B.
For example putSring("datafrom A","datafrom A");
Now in B i receive data From A.
I have one button in B,and i am sending data from B>C.
For example putSring("datafrom B","datafrom B");
Now in C i receive data From B.
Then, I have one Button in C,and sending data from C>B.
For example putSring("datafrom C","datafrom C");

So,seems like in B i am getting data from two different fragments. I tried with all using activity and it work well with startActivityforresult. but how can i manager when all are fragments.

Answer 1

UPDATE

Starting with Androidx Activity 1.2.0-alpha02 and Androidx Fragment 1.3.0-alpha4, the official Android developer guide recommends to use the Activity/Fragment Result APIs over the deprecated Activity.onActivityResult(int, int, Intent) and Fragment.setTargetFragment(Fragment, int) methods:

it is strongly recommended to use the Activity Result APIs introduced in AndroidX Activity 1.2.0-alpha02 and Fragment 1.3.0-alpha02.

Thus, to pass data back to fragment B from C, call setFragmentResultListener() on fragment B's FragmentManager, as shown in the following example:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    // Use the Kotlin extension in the fragment-ktx artifact
    setFragmentResultListener("requestKey") { requestKey, bundle ->
        // We use a String here, but any type that can be put in a Bundle is supported
        val result = bundle.getString("bundleKey")
        // Do something with the result
     }
}

In fragment C, set the result on the same FragmentManager by using the same requestKey using the setFragmentResult() API. Example:

setFragmentResult("requestKey", bundleOf("bundleKey" to "result"))

More details can be found at this guide.

---

The below answer is deprecated

You may call setTargetFragment() when you start the Fragment C from B. Example:

FragmentC fragmentC = FragmentC.newInstance();
fragmentC.setTargetFragment(FragmentB.this, REQUEST_CODE);
getFragmentManager().beginTransaction().replace(R.id.container, fragmentC).commit();

and then when you want to pass data back to fragment B from C, you can call the following code:

getTargetFragment().onActivityResult(
                getTargetRequestCode(),
                Activity.RESULT_OK,
                new Intent().putExtra("datafrom C", "datafrom C")
);

and get it from the onActivityResult() method in your fragment B:

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode==REQUEST_CODE && resultCode==Activity.RESULT_OK) {
        String datafromC = data.getStringExtra("datafrom C");   
    }
}