Question

尽管我在build.gradle中添加了实现，但编译器无法解析任何Firebase类

应用程序级别build.gradle

apply plugin: 'com.android.application'

repositories {
    google ()
    mavenLocal()
    flatDir {
        dirs 'libs'
    }
    jcenter()
}

android {
    compileSdkVersion 26
    buildToolsVersion '27.0.3'

    defaultConfig {
        applicationId "com.google.firebase.udacity.friendlychat"
        minSdkVersion 16
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    packagingOptions {
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE-FIREBASE.txt'
        exclude 'META-INF/NOTICE'
    }
}

dependencies {
    implementation 'com.firebaseui:firebase-ui-auth:4.1.0'

    implementation 'com.google.firebase:firebase-core:16.0.0'
    implementation 'com.google.firebase:firebase-database:16.0.1'
    implementation 'com.google.firebase:firebase-auth:16.0.2'

    implementation fileTree(dir: 'libs', include: ['*.jar'])
    testImplementation 'junit:junit:4.12'

    implementation 'com.android.support:design:26.2.0'
    implementation 'com.android.support:appcompat-v7:26.2.0'

    // Displaying images
    implementation 'com.github.bumptech.glide:glide:3.6.1'
}

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

项目级别build.gradle

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

buildscript {
    repositories {
        google()
        mavenLocal()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.2.0-alpha17'
        classpath 'com.google.gms:google-services:4.0.1'

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

allprojects {
    repositories {
        maven { url 'https://maven.google.com' }
        jcenter()
        mavenLocal()
    }
}

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

在主要活动中，IDE无法解析这些类中的任何一个，并且编译失败

private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference mMessagesDatabaseReference;
private ChildEventListener mChildEventListener;
private FirebaseAuth mFirabaseAuth;

我已将Gradle文件与项目同步，尝试过清理项目，尝试过重建项目。

Answer 1

点击文件->使用Gradle文件同步项目

有同样的问题，这对我来说已经解决了。

如果仍然无法正常运行，请尝试进行重建。

Answer 2

在应用程序build.gradle中添加依赖项

implementation 'com.google.firebase:firebase-database:16.0.5'
implementation 'com.google.firebase:firebase-core:16.0.5'

Answer 3

如果您尝试调用Firebase对象，并收到此错误：

错误：无法解析符号Firebase

您可能缺少依赖项。

确保将com.firebase：firebase-client添加到应用程序gradle中的依赖项中：

dependencies {

    implementation 'com.firebase:firebase-client-android:2.5.2'

Answer 4

如果您只是从Firebase文档复制粘贴代码，然后将以下库添加到Java文件：

import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

无法解析符号Firebase

4 个答案: