单击按钮后，Firebase应用程序停止工作

Question

我正在尝试将Firebase电子邮件密码身份验证集成到我的应用程序中，但是每当我单击登录或注册时，该应用程序就会崩溃。

这是我的代码：

import android.content.Intent
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import com.google.firebase.auth.FirebaseAuth
import kotlinx.android.synthetic.main.activity_login.*
class login : AppCompatActivity() {

    private var mAuth: FirebaseAuth? = null


    override fun onCreate(savedInstanceState: Bundle?) {


        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)

        mAuth = FirebaseAuth.getInstance()

        LoginButton.setOnClickListener {
            mAuth!!.signInWithEmailAndPassword(emailloginText.text.toString(),passwordLoginText.text.toString()).addOnCompleteListener {
                if (it.isSuccessful){
                    val i= Intent(this,MainScreen::class.java)
                    startActivity(i)
                    Toast.makeText(this,"Login successful",Toast.LENGTH_LONG).show()
                }
                else{
                    Toast.makeText(this,"login Fail",Toast.LENGTH_LONG).show()

                }
            }
        }
        RegisterButton.setOnClickListener {
            if(emailloginText.text.toString().isEmpty()&&passwordLoginText.text.toString().isEmpty()) {
                Toast.makeText(this, "Please fill in the required fields", Toast.LENGTH_SHORT).show()

                //if (editText2Pass.length() < 6) {
                //  Toast.makeText(getApplicationContext(), "Password must be at least 6 characters", Toast.LENGTH_SHORT).show();
            } else {
                mAuth!!.createUserWithEmailAndPassword(emailloginText.text.toString(), passwordLoginText.text.toString()).addOnCompleteListener {
                    if (it.isSuccessful) {
                        Toast.makeText(this, "Registration successful", Toast.LENGTH_LONG).show()
                    } else {
                        Toast.makeText(this, "Registration Fail", Toast.LENGTH_LONG).show()

                    }


                }
            }

        }
    }

}