Android app crashes with a flashing screen

Question

I am new to android development am learning to do authentication with firebase, i created three activity MainActivity, LoginActivity, and FeedActivity. what's happening is i am loading the app on my Xiaomi redmi phone with android 7.1.1 loaded, it opens up and looks to work fine, but am trying to signup with a new account, instead of taking me to the FeedActivity, it makes the whole screen flash in white, everything stops working, the only way to stop it is kill the application and go to home screen.

MainActivity

package com.example.ahmed.myapplication;

import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.text.TextUtils;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Button buttonRegister;
    private EditText editTextEmail;
    private EditText editTextPassword;
    private TextView textViewLogin;

    private ProgressDialog progressDialog;
    private FirebaseAuth firebaseAuth;

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

        firebaseAuth = FirebaseAuth.getInstance();
        if (firebaseAuth.getCurrentUser()!= null){
            finish();
            startActivity(new Intent(getApplicationContext(), FeedActivity.class));
        }
        progressDialog = new ProgressDialog(this);

        buttonRegister = (Button) findViewById(R.id.buttonRegister);

        editTextEmail = (EditText) findViewById(R.id.editTextEmail);
        editTextPassword = (EditText) findViewById(R.id.editTextPassword);

        textViewLogin = (TextView) findViewById(R.id.textViewLogin);

        buttonRegister.setOnClickListener(this);
        textViewLogin.setOnClickListener(this);
    }

    private void registerUser() {
        String email = editTextEmail.getText().toString().trim();
        String password = editTextPassword.getText().toString().trim();

        if (TextUtils.isEmpty(email)) {
            //email is empty
            Toast.makeText(this, "Opps! Please Enter Email", Toast.LENGTH_SHORT).show();
            //stop the function

            return;
        }

        if (TextUtils.isEmpty(password)) {
            //password is empty
            Toast.makeText(this, "Opps! Please Enter Password", Toast.LENGTH_SHORT).show();
            //stop the function

            return;
        }

        progressDialog.setMessage("Getting you in...");
        progressDialog.show();

        firebaseAuth.createUserWithEmailAndPassword(email,password)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {

                        if (task.isSuccessful()) {
                            firebaseAuth = FirebaseAuth.getInstance();
                                finish();
                                startActivity(new Intent(getApplicationContext(), FeedActivity.class));

                            Toast.makeText(MainActivity.this, "Welcome, to My App.", Toast.LENGTH_SHORT).show();
                        } else {
                            Toast.makeText(MainActivity.this, "Opps, Something went wrong! Try Again!!", Toast.LENGTH_SHORT).show();
                        }
                        progressDialog.dismiss();

                    }
                });
    }

    @Override
    public void onClick(View view) {
        if (view == buttonRegister) {
            registerUser();
        }

        if (view == textViewLogin) {
            startActivity(new Intent(this, LoginActivity.class));
        }

    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="16dp"
        android:paddingTop="16dp"
        android:paddingLeft="16dp"
        android:paddingRight="16dp"
        tools:context="com.example.ahmed.myapplication.MainActivity">


    <LinearLayout
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">


        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:text="Sign Up and Inspire!"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />



        <EditText
            android:layout_margin="15dp"
            android:inputType="textEmailAddress"
            android:hint="Enter Your Email"
            android:id="@+id/editTextEmail"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />


        <EditText
            android:layout_margin="15dp"
            android:inputType="textPassword"
            android:hint="Enter Your Password"
            android:id="@+id/editTextPassword"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

        <Button
            android:layout_margin="15dp"
            android:id="@+id/buttonRegister"
            android:text="Sign Up"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

        <TextView
            android:textAlignment="center"
            android:text="Already On signed up? Sign In Here"
            android:id="@+id/textViewLogin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />


    </LinearLayout>

    </RelativeLayout>

LoginActivity

package com.example.ahmed.myapplication;

import android.app.ProgressDialog;
import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;

public class LoginActivity extends AppCompatActivity implements View.OnClickListener {

    private Button buttonLogin;
    private EditText editTextEmail;
    private EditText editTextPassword;
    private TextView textViewSignup;

    private FirebaseAuth firebaseAuth;
    private ProgressDialog progressDialog;

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


        firebaseAuth = FirebaseAuth.getInstance();
        if (firebaseAuth.getCurrentUser()!= null){
            finish();
            startActivity(new Intent(getApplicationContext(), FeedActivity.class));
        }
        editTextEmail = (EditText) findViewById(R.id.editTextEmail);
        editTextPassword = (EditText) findViewById(R.id.editTextPassword);
        buttonLogin = (Button) findViewById(R.id.buttonLogin);
        textViewSignup = (TextView) findViewById(R.id.textViewSignup);

        progressDialog = new ProgressDialog(this);


        buttonLogin.setOnClickListener(this);
        textViewSignup.setOnClickListener(this);

    }

    private void userLogin() {
        String email = editTextEmail.getText().toString().trim();
        String password = editTextPassword.getText().toString().trim();

        if (TextUtils.isEmpty(email)) {
            //email is empty
            Toast.makeText(this, "Opps! Please Enter Email", Toast.LENGTH_SHORT).show();
            //stop the function

            return;
        }

        if (TextUtils.isEmpty(password)) {
            //password is empty
            Toast.makeText(this, "Opps! Please Enter Password", Toast.LENGTH_SHORT).show();
            //stop the function

            return;
        }

        progressDialog.setMessage("Finding Your Account...");
        progressDialog.show();

        firebaseAuth.signInWithEmailAndPassword(email,password)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        progressDialog.dismiss();
                        if (task.isSuccessful()){
                            finish();
                            startActivity(new Intent(getApplicationContext(), FeedActivity.class));
                        }

                    }
                });
    }

    @Override
    public void onClick(View view) {

        if (view == buttonLogin){
            userLogin();
        }

        if (view == textViewSignup){
            finish();
            startActivity(new Intent(this, MainActivity.class));
        }
    }
}

activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.ahmed.myapplication.LoginActivity">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:orientation="vertical"
        tools:layout_editor_absoluteX="0dp"
        tools:layout_editor_absoluteY="79dp">


        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:text="Welcome Back Buddy!"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />


        <EditText
            android:id="@+id/editTextEmail"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:hint="Enter Your Email"
            android:inputType="textEmailAddress" />


        <EditText
            android:id="@+id/editTextPassword"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:hint="Enter Your Password"
            android:inputType="textPassword" />

        <Button
            android:id="@+id/buttonLogin"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="15dp"
            android:text="Log In" />

        <TextView
            android:id="@+id/textViewSignup"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="New To My App? Sign Up Now"
            android:textAlignment="center" />


    </LinearLayout>

</android.support.constraint.ConstraintLayout>

FeedActivity

package com.example.ahmed.myapplication;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;

public class FeedActivity extends AppCompatActivity implements View.OnClickListener {

    private FirebaseAuth firebaseAuth;
    private TextView textViewUserEmail;
    private Button buttonLogout;

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


        firebaseAuth = FirebaseAuth.getInstance();
        if (firebaseAuth.getCurrentUser()!= null){
            finish();
            startActivity(new Intent(getApplicationContext(), LoginActivity.class));
        }

        FirebaseUser user = firebaseAuth.getCurrentUser();

        textViewUserEmail = (TextView) findViewById(R.id.textViewUserEmail);
        textViewUserEmail.setText("Welcome friend"+user.getEmail());
        buttonLogout = (Button) findViewById(R.id.buttonLogout);

        buttonLogout.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {

        if (view == buttonLogout){
            firebaseAuth.signOut();
            finish();
            startActivity(new Intent(this, LoginActivity.class));
        }
    }
}

Thanks for the help in advance

activity_feed.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.ahmed.myapplication.FeedActivity">

    <LinearLayout
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">


        <TextView
            android:id="@+id/textViewUserEmail"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:text="Ander Agaya te!"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Sign Out"
            android:id="@+id/buttonLogout"
            android:layout_gravity="center_horizontal" />
    </LinearLayout>
</android.support.constraint.ConstraintLayout>

why are you calling finish() before startActivity() in your MainActivity, FeedActivity and LoginActivity ? — yashkal, Jan 10 '18 at 05:11
white screen may be the finish calling first https://stackoverflow.com/questions/4182761/finish-old-activity-and-start-a-new-one-or-vice-versa — vikas kumar, Jan 10 '18 at 05:18

score 0 · Answer 1 · answered Jan 10 '18 at 05:14

Change this -:

if (task.isSuccessful()) {
                            firebaseAuth = FirebaseAuth.getInstance();
                                finish();
                                startActivity(new Intent(getApplicationContext(), FeedActivity.class));

                            Toast.makeText(MainActivity.this, "Welcome, to My App.", Toast.LENGTH_SHORT).show();
                        } else {
                            Toast.makeText(MainActivity.this, "Opps, Something went wrong! Try Again!!", Toast.LENGTH_SHORT).show();
                        }

To-:

if (task.isSuccessful()) {
                            firebaseAuth = FirebaseAuth.getInstance();

                                startActivity(new Intent(getApplicationContext(), FeedActivity.class));

finish();

                            Toast.makeText(MainActivity.this, "Welcome, to My App.", Toast.LENGTH_SHORT).show();
                        } else {
                            Toast.makeText(MainActivity.this, "Opps, Something went wrong! Try Again!!", Toast.LENGTH_SHORT).show();
                        }

Call finish after that line...

hey @Shivam Oberoi i did this, and the flashing is gone but my app get freezes, without even going to the FeedActivity, i tried stopping the app and opening it again but it freezes, and there is nothing in the logs — Noor Ali Khan, Jan 10 '18 at 18:40

Vinesh Chauhan · Answer 2 · 2018-01-10T05:42:14.650

0

make change in if condition in FeedActivity.class

 if (firebaseAuth.getCurrentUser()!= null){
            finish();
            startActivity(new Intent(getApplicationContext(), LoginActivity.class));
        }

to

 if (firebaseAuth.getCurrentUser()= null){

            startActivity(new Intent(getApplicationContext(), LoginActivity.class));
 finish();
            }

edited Jan 10 '18 at 05:42

answered Jan 10 '18 at 05:29

Vinesh Chauhan

1,288
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check my if condition – Vinesh Chauhan Jan 10 '18 at 05:41
Shivam repeated your answer @LUCKY – Vinesh Chauhan Jan 10 '18 at 05:43
hey @Vinesh Chauhan i tried this, and the flashing is gone but my app get freezes, without even going to the FeedActivity, i tried stopping the app and opening it again but it freezes, and there is nothing in the logs – Noor Ali Khan just now edit – Noor Ali Khan Jan 10 '18 at 18:41
you are answering same to two different solution so how we can get what solution worked for you – Vinesh Chauhan Jan 11 '18 at 06:01
your reply same as Shivam – Vinesh Chauhan Jan 11 '18 at 06:01
because may be none of the two solutions worked for me, i got the same issue with both the solutions – Noor Ali Khan Jan 12 '18 at 11:14

Android app crashes with a flashing screen

2 Answers2