App crash when using EditText [Android Studio] : I'm having a problem when trying to get data from "EditText" in Android Studio.
The app crashes immediately when I try to assign "EditText" value to a String variable (I used toString() method).

The problem is in the two lines after the onCreate method.

Here is my code:


    public class MainActivity extends AppCompatActivity {

    EditText em;
    EditText pw;
    private FirebaseAuth mAuth;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        EditText em = (EditText) findViewById(R.id.email1);
        EditText pw = (EditText) findViewById(R.id.password1);

        mAuth = FirebaseAuth.getInstance();
    }

    // When I remove those two lines the app runs normally
    String email = em.getText().toString(); 
    String password = pw.getText().toString();



    void login(View v){
        mAuth.signInWithEmailAndPassword(email, password)
                .addOnCompleteListener(MainActivity.this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            // Sign in success, update UI with the signed-in user's information
                            FirebaseUser user = mAuth.getCurrentUser();
                            String Logged = user.getEmail().toString();

                            Intent intent = new Intent(MainActivity.this, afterLogin.class);
                            intent.putExtra("email", Logged);
                            startActivity(intent);
                            finish();

                        } else {
                            // If sign in fails, display a message to the user.

                            Toast.makeText(MainActivity.this, "Wrong email/password.", Toast.LENGTH_SHORT).show();

                        }

                    }
                });
    }



}