FirebaseAuth返回null

Question

好的，当我点击注册按钮注册新用户时，它会给我以下行为。

错误：

  

尝试调用虚拟方法'com.google.android.gms.tasks.Task   com.google.android.gms.common.api.GoogleApi.zzb（com.google.android.gms.common.api.internal.zzdf）”   在空对象引用上

错误来源：

  

在   com.example.cmd.pop.Fragments.RegisterFragment $ 1.onClick（RegisterFragment.java:64）

它指向这一行：

mAuth.createUserWithEmailAndPassword(mail,pass)
                                .addOnCompleteListener(getActivity(), new OnCompleteListener<AuthResult>()

RegisterFragment类：

public class RegisterFragment extends Fragment {
private EditText mMail,mPass,mPassConf;
private Button mLogin,mRegister;
private FirebaseAuth mAuth;
private String mail,pass,passConf;

public RegisterFragment() {
    mAuth = FirebaseAuth.getInstance();
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.register_fragment_layout,container,false);
    find(v);
    onClick();
    return v;
}

private void find(View v) {
    mMail = (EditText)v.findViewById(R.id.registerName);
    mPass = (EditText)v.findViewById(R.id.registerPassword);
    mPassConf = (EditText)v.findViewById(R.id.registerPasswordConfirmation);
    mLogin = (Button)v.findViewById(R.id.btnLoginRegister);
    mRegister = (Button)v.findViewById(R.id.btnRegisterRegister);
}

private void onClick() {
    mRegister.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mail = mMail.getText().toString();
            pass = mPass.getText().toString();
            passConf = mPassConf.getText().toString();
            if(!isEmpty(mail) && !isEmpty(pass) && !isEmpty(passConf) ) {
                if(TextUtils.equals(pass,passConf)) {
                    mAuth.createUserWithEmailAndPassword(mail,pass)
                            .addOnCompleteListener(getActivity(), new OnCompleteListener<AuthResult>() {
                                @Override
                                public void onComplete(@NonNull Task<AuthResult> task) {
                                    if (task.isSuccessful()) {
                                        getActivity().startActivity(new Intent(getActivity(), MainActivity.class));
                                        getActivity().finish();
                                    } else {
                                        Toast.makeText(getActivity(), "Error registering....", Toast.LENGTH_SHORT).show();
                                    }
                                }
                            });

                } else {
                    Toast.makeText(getActivity(), "Password didn't match.", Toast.LENGTH_SHORT).show();
                }
            } else {
                Toast.makeText(getActivity(), "All fields need to be filled.", Toast.LENGTH_SHORT).show();
            }
        }
    });

    mLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Fragment loginFragment = new LoginFragment();
            getActivity().getSupportFragmentManager().beginTransaction()
                    .replace(R.id.loginActivityContainer,loginFragment).commit();

        }
    });

}

private boolean isEmpty(String name) {
    return TextUtils.isEmpty(name);
}

应用级Gradle

 apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "27.0.0"
    defaultConfig {
        applicationId "com.example.cmd.pop"
        minSdkVersion 19
        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 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.android.support:support-v4:26.1.0'
    implementation 'com.google.firebase:firebase-database:11.6.0'
    implementation 'com.google.firebase:firebase-auth:11.6.0'
    compile 'com.android.support:design:26.1.0'
    compile 'com.android.support:cardview-v7:26.1.0'
    compile 'com.android.support:recyclerview-v7:26.1.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation('com.android.support.test.espresso:espresso-core:3.0.1', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
}




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

项目级别Gradle

   // Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.0-alpha03'


        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
        classpath 'com.google.gms:google-services:3.1.0'
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

Answer 1

在验证控制台中启用的电子邮件/密码后，尝试将firebase降级到较早版本

implementation 'com.google.firebase:firebase-auth: 9.6.0'

Answer 2

我解决了错误，问题出在模拟器中我需要更新模拟器上的google play服务，并且在更新后一切正常。