我刚开始整合Firebase。

在firebase指导下执行基本步骤后，运行项目时出现错误。

我的应用程序build.gradle

buildscript {
    ext.kotlin_version = '1.2.71'
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.2.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.gms:google-services:4.0.1'
    }
}

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

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

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

我的android build.gradle

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 28

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationid "com.rental.asp.rental_actual"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now,so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    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-analytics:17.2.0'
}
apply plugin: 'com.google.gms.google-services'

当我构建时，这就是输出

21:30:55.498 1 info flutter.tools launching lib\main.dart on SM N975U1 in debug mode...
21:30:55.505 2 info flutter.tools Initializing gradle...
21:30:56.251 3 info flutter.tools Resolving dependencies...
21:31:02.480 4 info flutter.tools Running Gradle task 'assembleDebug'...
21:31:05.312 5 info flutter.tools registerResGeneratingTask is deprecated,use registerGeneratedResFolders(FileCollection)
21:31:05.313 6 info flutter.tools registerResGeneratingTask is deprecated,use registerGeneratedResFolders(FileCollection)
21:31:05.313 7 info flutter.tools registerResGeneratingTask is deprecated,use registerGeneratedResFolders(FileCollection)
21:31:12.464 8 info flutter.tools H:\Rental\rental\rental_actual\android\app\src\debug\AndroidManifest.xml:22:18-91 Error:
21:31:12.464 9 info flutter.tools   Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0] AndroidManifest.xml:22:18-91
21:31:12.464 10 info flutter.tools  is also present at [androidx.core:core:1.0.0] AndroidManifest.xml:22:18-86 value=(androidx.core.app.CoreComponentFactory).
21:31:12.464 11 info flutter.tools 
21:31:12.464 12 info flutter.tools  Suggestion: add 'tools:replace="android:appComponentFactory"' to <application> element at AndroidManifest.xml:9:5-32:19 to override.
21:31:12.464 13 info flutter.tools 
21:31:12.464 14 info flutter.tools FAILURE: Build failed with an exception.
21:31:12.464 15 info flutter.tools 
21:31:12.464 16 info flutter.tools * What went wrong:
21:31:12.465 17 info flutter.tools Execution failed for task ':app:processDebugManifest'.
21:31:12.465 18 info flutter.tools > Manifest merger failed : Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0] AndroidManifest.xml:22:18-91
21:31:12.465 19 info flutter.tools      is also present at [androidx.core:core:1.0.0] AndroidManifest.xml:22:18-86 value=(androidx.core.app.CoreComponentFactory).
21:31:12.465 20 info flutter.tools      Suggestion: add 'tools:replace="android:appComponentFactory"' to <application> element at AndroidManifest.xml:9:5-32:19 to override.
21:31:12.465 21 info flutter.tools 
21:31:12.465 22 info flutter.tools * Try:
21:31:12.465 23 info flutter.tools Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
21:31:12.465 24 info flutter.tools 
21:31:12.466 25 info flutter.tools * Get more help at https://help.gradle.org
21:31:12.466 26 info flutter.tools 
21:31:12.466 27 info flutter.tools BUILD FAILED in 9s

也在我的android / build.gradle第一行中

def localProperties = new Properties()

＆

throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")

获取“无法解析符号”