Question

我无法首先初始化Firebase应用

我在gradle：app中添加了这些插件

implementation 'com.google.firebase:firebase-core:16.0.1'
implementation 'com.google.firebase:firebase-auth:16.0.3'

（我试图使它们版本相同）

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

我也将其添加到gradle：project

classpath 'com.google.gms:google-services:4.1.0'

最后，我将其添加到MainActivity中的onCreate（）

FirebaseApp.initializeApp(this);

<<<< AndroidManifest >>>>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.firebasetest">

    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

<<<< MainActivity >>>>

package com.example.firebasetest;

import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.FirebaseApp;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;

public class MainActivity extends AppCompatActivity {

    private FirebaseAuth mAuth;

    String email;
    String password;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FirebaseApp.initializeApp(this);

        mAuth = FirebaseAuth.getInstance();

        ...

    }

    @Override
    public void onStart() {
        super.onStart();
        // Check if user is signed in (non-null) and update UI accordingly.

        ...
    }

    private void updateUI(FirebaseUser currentUser) {
    }
}

<<<<<<<<<< gradle：app >>>>>>>>>>

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.firebasetest"
        minSdkVersion 15
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'com.google.firebase:firebase-core:16.0.1'
    implementation 'com.google.firebase:firebase-auth:16.0.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}
apply plugin: 'com.google.gms.google-services'

<<<<<<<<<< gradle：project >>>>>>>>>>

// 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:3.3.2'
        classpath 'com.google.gms:google-services:4.1.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()

    }
}

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

我希望它能正常工作。但是安装该应用程序后，它甚至没有显示MainActivity

错误消息如下：

E / Android运行时：致命异常：主要流程：com.example.firebasetest，PID：18544 java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.firebasetest / com.example.firebasetest.MainActivity}：java.lang.IllegalStateException：默认FirebaseApp在此过程com.example.firebasetest中未初始化。确保首先调用FirebaseApp.initializeApp（Context）。在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:3086）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:3229）在android.app.servertransaction.LaunchActivityItem.execute（LaunchActivityItem.java:78）在android.app.servertransaction.TransactionExecutor.executeCallbacks（TransactionExecutor.java:108）在android.app.servertransaction.TransactionExecutor.execute（TransactionExecutor.java:68）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1926）在android.os.Handler.dispatchMessage（Handler.java:106）在android.os.Looper.loop（Looper.java:214）在android.app.ActivityThread.main（ActivityThread.java:6981）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.RuntimeInit $ MethodAndArgsCaller.run（RuntimeInit.java:493）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1445）由以下原因引起：java.lang.IllegalStateException：在此过程com.example.firebasetest中未初始化默认的FirebaseApp。确保首先调用FirebaseApp.initializeApp（Context）。在com.google.firebase.FirebaseApp.getInstance（SourceFile：218）在com.google.firebase.auth.FirebaseAuth.getInstance上（未知来源：1）在com.example.firebasetest.MainActivity.onCreate（MainActivity.java:30）在android.app.Activity.performCreate（Activity.java:7326）在android.app.Activity.performCreate（Activity.java:7317）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1271）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:3066）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:3229）在android.app.servertransaction.LaunchActivityItem.execute（LaunchActivityItem.java:78）在android.app.servertransaction.TransactionExecutor.executeCallbacks（TransactionExecutor.java:108）在android.app.servertransaction.TransactionExecutor.execute（TransactionExecutor.java:68）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1926）在android.os.Handler.dispatchMessage（Handler.java:106）在android.os.Looper.loop（Looper.java:214）在android.app.ActivityThread.main（ActivityThread.java:6981）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.RuntimeInit $ MethodAndArgsCaller.run（RuntimeInit.java:493）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1445）

Answer 1

更改此行

classpath 'com.google.gms:google-services:4.1.0'

此行

classpath 'com.google.gms:google-services:4.2.0'

我认为Google Play服务版本4.1.0有一个错误

Answer 2

确保将apply plugin: 'com.google.gms.google-services'放入应用gradle中

Answer 3

您需要更新类路径和Firebase身份验证版本改变这个

classpath 'com.google.gms:google-services:4.1.0'

对此 classpath 'com.google.gms:google-services:4.2.0'

要获得更好的结果，只需更新Firebase身份验证。

This is how you can update

错误消息：请确保先调用FirebaseApp.initializeApp（Context）

3 个答案: