CODEWITHSUNDEEP
javaandroidandroid-fragmentsandroid-activity
Sarvesh Mehra
Sarvesh Mehra

Reputation: 19

How to access fragment elements via adapter?

I have LoginActivity.class, that uses adapter on onCreate()

final LoginAdapter loginAdapter = new LoginAdapter(getSupportFragmentManager(), this, tabLayout.getTabCount());
    viewPager.setAdapter(loginAdapter);
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

LoginAdapter.class

public class LoginAdapter extends FragmentPagerAdapter {

private Context context;
int totalTabs;

public LoginAdapter(@NonNull FragmentManager fm,Context context, int totalTabs) {
    super(fm);
    this.context = context;
    this.totalTabs = totalTabs;
}

@Override
public int getCount() {
    return totalTabs;
}

public Fragment getItem(int position){

    switch (position){
        case 0:
            LoginTabFragment loginTabFragment = new LoginTabFragment();
            return loginTabFragment;
        case 1:
            RegisterTabFragment registerTabFragment = new RegisterTabFragment();
            return registerTabFragment;
        default:
            return null;
    }}}

LoginTabFragment.class

public class LoginTabFragment extends Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    ViewGroup root = (ViewGroup) inflater.inflate(R.layout.login_tab_fragment, container, false);
    return root;
}}

LoginActivity need to get access to fields which are at login_tab_fragment.xml.

userNameInput = findViewById(R.id.login_username_input);
passwordInput = findViewById(R.id.login_password_input);
loginBtn = findViewById(R.id.login_email_login_btn);
loginBtn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

    }
});

I get NPE:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778)

How do I get access to elements of LoginTabFragment in LoginActivity? Thank you.

Upvotes: 1

Views: 186

Answers (1)

Morpheus
Morpheus

Reputation: 572

You can define public method in your activity that you can call

  1. Define this method in your activity

    public void responseFromFragment(View v){
//do your things in activity
}

  2. Call method from Fragment

    loginBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
((YourActivityClassName)getActivity()).responseFromFragment(v);
}

I don't recommend this way you going You can do everything in Fragment you dont need to pass ref to activity Please learn more about fragment

Upvotes: 1

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