How to solve app crashing when using an intent in a fragment?

Question

I have designed a login page using Viewpager(login page and register page) and set a fragment to load on that ViewPager when using intend for login button to go the next page after login it crashes

note:I have simply made login button to intent to next page even there is nothing in username and password just to test everything works fine

Here is my Java coding:

public class LoginFragment extends Fragment{
    View view;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable 
        ViewGroup container, @Nullable Bundle savedInstanceState) {
        final Button b = null;
        b.findViewById(R.id.Loginbutton);
        final EditText e = getView().findViewById(R.id.user);
        EditText e1 = getView().findViewById(R.id.pass);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent l = new Intent(getActivity(), AfterLogin.class);
                startActivity(l);
            }
        });
        view = inflater.inflate(R.layout.fragment_login,container,false);

        return view;
    }

    public LoginFragment() {}
}

There is no error but during runtime it makes the app crash...

Here is my XML:

   <?xml version="1.0" encoding="utf-8"?>
   <android.widget.RelativeLayout 
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:background="@color/DefaultWhite">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="125dp"
    android:text="@string/app_name"
    android:textColor="@color/colorPrimaryDark"
    android:textSize="30sp" />
<ImageView
    android:contentDescription="@string/LoginText"
    android:id="@+id/imageView4"
    android:layout_width="48dp"
    android:layout_height="57dp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="78dp"
    app:srcCompat="@drawable/accountbox" />

    <EditText
        android:id="@+id/user"
        android:inputType="text"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:hint="@string/LoginText"
        android:gravity="center"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="300dp"
        android:layout_marginRight="20dp"
        android:background="@drawable/loginpageloginedittext"
        />
    <EditText
        android:id="@+id/pass"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:hint="@string/PasswordText"
        android:gravity="center"
        android:layout_marginEnd="20dp"
        android:layout_marginTop="360sp"
        android:background="@drawable/loginpageedittextpassword"
        android:layout_marginStart="20dp"
        android:inputType="textPassword"
        />

    <Button
        android:id="@+id/LoginButton"
        android:layout_width="175dp"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginTop="450dp"
        android:background="@drawable/loginbutton"
        android:layout_marginStart="20dp"
        android:textColor="@color/DefaultWhite"
        android:layout_marginEnd="20dp"
        android:text="@string/LoginButton" />

    <Button
        android:id="@+id/registerbutton"
        android:layout_width="175dp"
        android:layout_height="wrap_content"
        android:background="@drawable/forgotpasswordbutton"
        android:layout_marginTop="450dp"
        android:layout_marginStart="215dp"
        android:layout_marginBottom="10dp"
        android:text="@string/ForgotPassword" />



    <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="600dp"
    android:layout_marginStart="160dp"
    android:hint="@string/KnowUsMore" />
   </android.widget.RelativeLayout>

`There is no error ...` maybe no **syntactical** error. But, for sure, there's some **logical** one. You can analyze your logcat and find it. — Phantômaxx, May 22 '18 at 07:49
You're trying to use `getView()` before the view is even created hence the `NullPointerException`. Move logic that uses this method into `onViewCreated()` — Mark, May 22 '18 at 07:52

score 0 · Accepted Answer · edited May 22 '18 at 08:57

avoid view.findViewById() instead of getView() i edit your code and given below. check it... Happy Coding ;-)

public class LoginFragment extends Fragment{

View view;

@Nullable
@Override

public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {



    view = inflater.inflate(R.layout.fragment_login,container,false);
    return view;


}

@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {

    Button b = view.findViewById(R.id.Loginbutton);
    EditText e = view.findViewById(R.id.user);
    EditText e1 = view.findViewById(R.id.pass);
    b.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent l = new Intent(getActivity(), AfterLogin.class);
            startActivity(l);
        }
    });
    super.onViewCreated(view, savedInstanceState);
}

public LoginFragment() {}

}

Update: I changed these button intialization and onclicklistener under onViewCreated() method and it worked.Thanks for the help! — Jithin Joseph, May 22 '18 at 08:54

How to solve app crashing when using an intent in a fragment?

1 Answers1