java - Android应用程序无法连接到firebase数据库

Question

我正在尝试将写入数据连接到我的 firebase 数据库，但它显示错误，尽管我已经初始化了 firebase，但它尚未初始化。我已经尝试更改依赖项等，但仍然无法正常工作

package com.parse.starter;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        FirebaseApp.initializeApp(this);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FirebaseApp.initializeApp(this);
        DatabaseReference ref=FirebaseDatabase.getInstance().getReference();
        Map<String,String> values=new HashMap<>();
        values.put("name","Jeff");
        ref.push().setValue(values,new DatabaseReference.CompletionListener()
        {

            @Override
            public void onComplete(@Nullable DatabaseError databaseError, @NonNull DatabaseReference databaseReference) {
                if(databaseError==null)
                {
                    Log.i("info","Get to job");
                }
                else
                {
                    Log.i("info","Stay here");
                }
            }
        });
    }
}

gradle文件

buildscript {
    repositories {
        google()
        jcenter()

    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.3.0'
        classpath 'com.google.gms:google-services:4.2.0'

        // 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
}

应用程序/gradle

apply plugin: 'com.android.application'


android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.parse.starter"
        minSdkVersion 14
        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-database:16.1.0'
    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'
    implementation 'com.google.firebase:firebase-core:16.0.3'
}

Answer 1

无需调用:

FirebaseApp.initializeApp(this);

如果您按照官方文档中有关如何 add Firebase to your Android project 的说明执行了集成。

如果您执行了上述标准集成，Firebase 将在您的应用启动时自动初始化。请参阅此处有关 FirebaseApp 的更多详细信息.

要解决此问题，请更改以下代码行:

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

至

implementation 'com.google.firebase:firebase-core:16.0.8'

如果您没有执行上述标准集成，您应该在需要时调用 initializeApp。