在kotlin android studio中登录firebase

Question

我在我的android项目中使用firebase。但这是什么得到当用户试图注册在firebase使用我的应用程序。

我的错误日志

09-15 13:54:23.992 2716-2716/com.example.err0r1096.tikteck E/AndroidRuntime: FATAL EXCEPTION: main
                                                                         Process: com.example.err0r1096.tikteck, PID: 2716

java.lang.IllegalStateException: Could not execute method for android:onClick
     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
     at android.view.View.performClick(View.java:5637)
     at android.view.View$PerformClick.run(View.java:22429)
     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$MethodAndArgsCaller.run(ZygoteInit.java:886)
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
  Caused by: java.lang.reflect.InvocationTargetException
     at java.lang.reflect.Method.invoke(Native Method)
     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
     at android.view.View.performClick(View.java:5637) 
     at android.view.View$PerformClick.run(View.java:22429) 
     at android.os.Handler.handleCallback(Handler.java:751) 
     at android.os.Handler.dispatchMessage(Handler.java:95) 
     at android.os.Looper.loop(Looper.java:154) 
     at android.app.ActivityThread.main(ActivityThread.java:6119) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 
  Caused by: kotlin.KotlinNullPointerException
     at com.example.err0r1096.tikteck.Login.LoginToFireBase(Login.kt:26)
     at com.example.err0r1096.tikteck.Login.OneC(Login.kt:20)
     at java.lang.reflect.Method.invoke(Native Method) 
     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
     at android.view.View.performClick(View.java:5637) 
     at android.view.View$PerformClick.run(View.java:22429) 
     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 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

这是我的代码：

package com.example.err0r1096.tikteck

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Toast
import com.google.firebase.auth.FirebaseAuth
import kotlinx.android.synthetic.main.activity_login.*


class Login : AppCompatActivity() {

    private val mAuth: FirebaseAuth? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)
    }
    fun OneC(view: View){

        LoginToFireBase(etEmail.text.toString(),etPassword.text.toString())

    }

    fun LoginToFireBase(email:String,password:String){

        mAuth!!.createUserWithEmailAndPassword(email,password)
                .addOnCompleteListener(this){ task ->

                    if (task.isSuccessful){
                        Toast.makeText(applicationContext,"Successful login",Toast.LENGTH_LONG).show()
}
                else
                {
                    Toast.makeText(this,"Login UnSuccessful",Toast.LENGTH_LONG).show()
                }
        }
    }
}

Answer 1

您可以查看官方文档：

Kotlin的类型系统旨在从代码中消除NullPointerException。NPE的唯一可能原因可能是：

>

抛出NullPointerException（）的显式调用；

使用：b！！将返回b的non-null值，如果b为null则抛出npe

检查您的代码（您使用kotlin作为java）

mAuth!!.createUserWithEmailAndPassword(email,password)

您是否在任何地方初始化了mauth？如果没有，则mauth！！将抛出NullPointerException