Firebase Auth causing Fatal exeception: (java.lang.NullPointerException)-CodePudding

This worked perfectly fine from the time i created the project. But suddenly is starts crashing. The sign up activity works fine. But this sign in activity is crashing.

The error shown by the debugger.

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.durden, PID: 7921
    java.lang.NullPointerException
        at com.example.durden.activity.SignInActivity.onCreate$lambda-2(SignInActivity.kt:49)
        at com.example.durden.activity.SignInActivity.$r8$lambda$ZBrxDCm4vr69l-PuE690AA_KCF8(Unknown Source:0)
        at com.example.durden.activity.SignInActivity$$ExternalSyntheticLambda1.onClick(Unknown Source:4)
        at android.view.View.performClick(View.java:7125)
        at android.view.View.performClickInternal(View.java:7102)
        at android.view.View.access$3500(View.java:801)
        at android.view.View$PerformClick.run(View.java:27336)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

The signin Activity


class SignInActivity : AppCompatActivity() {

    // getting the references from firebase
    private var auth: FirebaseAuth? = null
    private var firebaseUser: FirebaseUser? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // gets the view binding of sign_in_activity
        val binding = ActivitySignInBinding.inflate(layoutInflater)

        setContentView(binding.root)

        // ends this activity and goes to sign up page if needed
        binding.gotoSignUp.setOnClickListener {
            val intent = Intent(
                this@SignInActivity,
                SignUpActivity::class.java
            )
            startActivity(intent)
            finish()
        }

        binding.btnSignIn.setOnClickListener {

            // storing the entered email and password
            val email = binding.SImail.text.toString()
            val password = binding.SIpass.text.toString()

            // checks if the values are entered
            if (TextUtils.isEmpty(email) && TextUtils.isEmpty(password)) {
                Toast.makeText(applicationContext,"email and password are required", Toast.LENGTH_SHORT).show()
            }

            // signs in the user using firebase data
            else {
                auth!!.signInWithEmailAndPassword(email, password)
                    .addOnCompleteListener(this) {
                        if (it.isSuccessful) {
                            binding.SImail.setText("")
                            binding.SIpass.setText("")

                            // after sign in takes to user page
                            val intent = Intent(
                                this@SignInActivity,
                                UserActivity::class.java
                            )
                            startActivity(intent)
                            finish()
                        }
                        else {
                            Toast.makeText( applicationContext, "Invalid password or email", Toast.LENGTH_SHORT).show()
                        }
                    }
            }
        }

    }
}

Firebase Authentication causing Android fatal exception

This sounds similar to my problem but still i couldn't figure why it happens so.

And Thank you for your help!

CodePudding user response：

You never initialize auth, which means that by the time you execute auth!!.signInWithEmailAndPassword(email, password) you get an exception.

Initialize auth like shown in step 2 here in your onCreate to prevent the error.

// Initialize Firebase Auth
auth = Firebase.auth

NullPointerExceptions are very common, so I highly recommend learning how to troubleshoot these yourself. For that, check out: