Right Approach to Call Web Service(API) from Fragment class

Question

I need to know, In which fragment callback method, we should call a web service by which after come back to fragment web service should not call again.

For example.

Answer 1

onCreate() is tricky.

Put everything that you want to call just once in onCreate() method. For example your API call, list, adapter initialization.

So ideally I would do like this

public void onCreate(Bundle sis) {

    getImagesFromServer(); // API Call 
    initialzeLists()
    initializeAdapters()

}

public View onCreateView(LayoutInflater i, ViewGroup c,Bundle sis) {
    recyclerView = findViewById()
    setUpAdapters()
    return rootView;
}

TRICKY PART

But if you really want onCreate() to be called once then reuse Fragment. (Don't create a new instance every time).

How to reuse a Fragment?

While Adding for first time use add it to backStack with a KEY like this

currentFragment = FirstFragment.getInstance();
getSupportFragmentManager()
            .beginTransaction()
            .replace(R.id.fragmentHolder, currentFragment, "FIRST_KEY")
            .addToBackStack("FIRST_KEY")
            .commit();

And when you want to add it again get the old instance with the KEY like this

currentFragment = getSupportFragmentManager().findFragmentByTag("FIRST_KEY");
getSupportFragmentManager()
            .beginTransaction()
            .replace(R.id.fragmentHolder, currentFragment, "FIRST_KEY")
            .addToBackStack("FIRST_KEY")
            .commit();

Demo project:

Here is the link to a demo project which loads a list of images using the Volley library. It has a similar implementation.

Woof - Use fragments the right way