使用时出错 Firebase Android Studio (kotlin)

Question

I'm trying to make a project with Firebase login and signup, I'm trying now to make the signup activity, I attach the code here:

import android.content.Intent
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.text.TextUtils
import android.view.View
import android.widget.EditText
import android.widget.ProgressBar
import android.widget.Toast
import com.google.firebase.auth.FirebaseAuth
import com.google.firebase.auth.FirebaseUser
import com.google.firebase.database.DatabaseReference
import com.google.firebase.database.FirebaseDatabase

class RegisterActivity : AppCompatActivity() {

    private lateinit var txtName:EditText
    private lateinit var txtLastName:EditText
    private lateinit var txtEmail:EditText
    private lateinit var txtPassword:EditText
    private lateinit var progressBar:ProgressBar
    private lateinit var dbReference:DatabaseReference
    private lateinit var database:FirebaseDatabase
    private lateinit var auth:FirebaseAuth

    override fun onCreate(savedInstanceState: Bundle?){
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_register)

        txtName=findViewById(R.id.txtName)
        txtLastName=findViewById(R.id.txtLastName)
        txtEmail=findViewById(R.id.txtEmail)
        txtPassword=findViewById(R.id.txtPassword)

        progressBar=findViewById(R.id.progressBar)

        database= FirebaseDatabase.getInstance()
        auth= FirebaseAuth.getInstance()

        dbReference=database.reference.child("Usuarios")

    }

    fun registrarse(view:View){
        createNewAccount()
    }
    fun login(view:View) {
        startActivity(Intent(this,LoginActivity::class.java))
    }
    private fun createNewAccount(){
        val name:String=txtName.text.toString()
        val lastName:String=txtLastName.text.toString()
        val email:String=txtEmail.text.toString()
        val password:String=txtPassword.text.toString()

        if(!TextUtils.isEmpty(name) && !TextUtils.isEmpty(lastName) && !TextUtils.isEmpty(email) && !TextUtils.isEmpty(password)){
            progressBar.visibility=View.VISIBLE

            auth.createUserWithEmailAndPassword(email,password)
                    ?.addOnCompleteListener(this){

                        task ->

                        if(task.isComplete){
                            val user:FirebaseUser?=auth.currentUser
                            verifyEmail(user)

                            val userBD=dbReference.child(user?.uid)

                            userBD.child("Nombre").setValue(name)
                            userBD.child("Apellidos").setValue(lastName)
                            userBD.child("Correo electrónico").setValue(email)
                            action()
                        }

                    }
        }



    }
    private fun verifyEmail(user:FirebaseUser?){
        user?.sendEmailVerification()
                ?.addOnCompleteListener(this){
                    task ->

                    if(task.isComplete){
                        Toast.makeText(this, "Correo de verificación enviado.",Toast.LENGTH_LONG).show()
                    }
                    else{
                        Toast.makeText(this, "Error al enviar el correo de verificación.",Toast.LENGTH_LONG).show()
                    }
                }
    }
    private fun action(){
        startActivity(Intent(this,LoginActivity::class.java))
    }

}

When I press button "registrarse", app crashes... My gradle file (App) is the following:

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 26
    defaultConfig {
        applicationId "com.example.uburr.hastalos"
        minSdkVersion 24
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
    implementation 'com.google.firebase:firebase-core:12.0.1'
    implementation 'com.google.firebase:firebase-database:12.0.1'
    implementation 'com.google.firebase:firebase-auth:12.0.1'
    implementation 'com.google.firebase:firebase-storage:12.0.1'
    implementation 'com.google.firebase:firebase-messaging:12.0.1'

}
apply plugin: 'com.google.gms.google-services'

Compiler doesn't show any error. I'm new to this, so I really don't know how to fix this... I'm trying to learn, I think this forum will help me, I'll be very grateful to everyone that try to help.

03-30 17:23:03.636 12627-12627/com.example.uburr.hastalos E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.uburr.hastalos, PID: 12627 java.lang.NullPointerException: Can't pass null for argument 'pathString' in child() at com.google.firebase.database.DatabaseReference.child(Unknown Source) at com.example.uburr.hastalos.RegisterActivity$createNewAccount$1.onComplete(RegisterActivity.kt:69) at com.google.android.gms.tasks.zzf.run(Unknown Source) at android.os.Handler.handleCallback(Handler.java:751) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6119) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at 88168970 007088.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 03-30 17:23:14.789 12627-12733/com.example.uburr.hastalos I/Adreno: DequeueBuffer: dequeueBuffer failed 03-30 17:23:14.789 12627-12733/com.example.uburr.hastalos I/Adreno: DequeueBuffer: dequeueBuffer failed 03-30 17:23:14.793 12627-12733/com.example.uburr.hastalos W/OpenGLRenderer: swapBuffers encountered EGL error 12301 on 0x7f6b9f2380, halting rendering...

Thanks a lot, Miguel Angel.

Answer 1

The problem is here, you're checking if the task is complete and then try to access the user, but if the task is not successfull the user will be null:

 if(task.isComplete){
                            val user:FirebaseUser?=auth.currentUser
                            verifyEmail(user)

                            val userBD=dbReference.child(user?.uid)

                            userBD.child("Nombre").setValue(name)
                            userBD.child("Apellidos").setValue(lastName)
                            userBD.child("Correo electrónico").setValue(email)
                            action()
                        }

You should do instead, check if the task is succesfull and then act on it:

if(task.isSuccessful){
                            val user:FirebaseUser?=auth.currentUser
                            verifyEmail(user)

                            val userBD=dbReference.child(user?.uid)

                            userBD.child("Nombre").setValue(name)
                            userBD.child("Apellidos").setValue(lastName)
                            userBD.child("Correo electrónico").setValue(email)
                            action()
                        }

Answer 2

You need to add in your gradle (:app) > dependencies

implementation 'com.google.firebase:firebase-auth-ktx'