Ionic+Capacitor集成推送通知后Android编译报错：无法访问Service

安装@capacitor/push-notifications包后，Android Studio构建时出现以下错误：

../node_modules@capacitor\push-notifications\android\src\main\java\com\capacitorjs\plugins\pushnotifications\MessagingService.java:7: error: cannot access Service
public class MessagingService extends FirebaseMessagingService {
^
class file for android.app.Service not found

1. 更新Gradle相关插件版本 #

根目录build.gradle中使用的Gradle插件版本4.2.1与Capacitor 4.x兼容性不足，需升级到适配版本：

// 替换原Android Gradle插件版本
classpath 'com.android.tools.build:gradle:7.0.4'
// 同步升级Google服务插件版本
classpath 'com.google.gms:google-services:4.3.14'

2. 调整仓库配置 #

将google()仓库放在所有仓库列表最前面，同时替换已停止维护的jcenter()为mavenCentral()：

// buildscript和allprojects块下的repositories都修改为：
repositories {
    google()
    mavenCentral()
}

3. 补充Firebase依赖 #

在app模块的build.gradle的dependencies块中添加Firebase Messaging依赖：

implementation 'com.google.firebase:firebase-messaging:23.0.0'

4. 同步并清理项目 #

• 在Android Studio中点击File > Sync Project with Gradle Files完成依赖同步
• 执行命令清理并重新构建：./gradlew clean build

package.json #

{
  "name": "push-notifications-app",
  "version": "0.0.1",
  "author": "Ionic Framework",
  "homepage": "https://ionicframework.com/",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "^14.0.0",
    "@angular/core": "^14.0.0",
    "@angular/forms": "^14.0.0",
    "@angular/platform-browser": "^14.0.0",
    "@angular/platform-browser-dynamic": "^14.0.0",
    "@angular/router": "^14.0.0",
    "@capacitor/android": "4.0.1",
    "@capacitor/app": "4.0.1",
    "@capacitor/core": "4.0.1",
    "@capacitor/haptics": "4.0.1",
    "@capacitor/keyboard": "4.0.1",
    "@capacitor/push-notifications": "^4.0.1",
    "@capacitor/status-bar": "4.0.1",
    "@ionic/angular": "^6.1.9",
    "rxjs": "~6.6.0",
    "tslib": "^2.2.0",
    "zone.js": "~0.11.4"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^14.0.0",
    "@angular-eslint/builder": "~13.0.1",
    "@angular-eslint/eslint-plugin": "~13.0.1",
    "@angular-eslint/eslint-plugin-template": "~13.0.1",
    "@angular-eslint/template-parser": "~13.0.1",
    "@angular/cli": "^14.0.0",
    "@angular/compiler": "^14.0.0",
    "@angular/compiler-cli": "^14.0.0",
    "@angular/language-service": "^14.0.0",
    "@capacitor/cli": "4.0.1",
    "@ionic/angular-toolkit": "^6.0.0",
    "@types/jasmine": "~3.6.0",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "^12.11.1",
    "@typescript-eslint/eslint-plugin": "5.3.0",
    "@typescript-eslint/parser": "5.3.0",
    "eslint": "^7.6.0",
    "eslint-plugin-import": "2.22.1",
    "eslint-plugin-jsdoc": "30.7.6",
    "eslint-plugin-prefer-arrow": "1.2.2",
    "jasmine-core": "~3.8.0",
    "jasmine-spec-reporter": "~5.0.0",
    "karma": "~6.3.2",
    "karma-chrome-launcher": "~3.1.0",
    "karma-coverage": "~2.0.3",
    "karma-coverage-istanbul-reporter": "~3.0.2",
    "karma-jasmine": "~4.0.0",
    "karma-jasmine-html-reporter": "^1.5.0",
    "protractor": "~7.0.0",
    "ts-node": "~8.3.0",
    "typescript": "~4.7.3"
  },
  "description": "An Ionic project"
}

Android根目录build.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:4.2.1'
        classpath 'com.google.gms:google-services:4.3.5'

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

apply from: "variables.gradle"

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

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

Android app模块build.gradle #

apply plugin: 'com.android.application'

android {
    compileSdkVersion rootProject.ext.compileSdkVersion
    defaultConfig {
        applicationId "io.ionic.starter"
        minSdkVersion rootProject.ext.minSdkVersion
        targetSdkVersion rootProject.ext.targetSdkVersion
        versionCode 1
        versionName '1.0.0-1'
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        aaptOptions {
             // Files and dirs to omit from the packaged assets dir, modified to accommodate modern web apps.
             // Default: https://android.googlesource.com/platform/frameworks/base/+/282e181b58cf72b6ca770dc7ca5f91f135444502/tools/aapt/AaptAssets.cpp#61
            ignoreAssetsPattern '!.svn:!.git:!.ds_store:!*.scc:.*:!CVS:!thumbs.db:!picasa.ini:!*~'
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

repositories {
    flatDir{
        dirs '../capacitor-cordova-android-plugins/src/main/libs', 'libs'
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation "androidx.appcompat:appcompat:$androidxAppCompatVersion"
    implementation project(':capacitor-android')
    testImplementation "junit:junit:$junitVersion"
    androidTestImplementation "androidx.test.ext:junit:$androidxJunitVersion"
    androidTestImplementation "androidx.test.espresso:espresso-core:$androidxEspressoCoreVersion"
    implementation project(':capacitor-cordova-android-plugins')
}

apply from: 'capacitor.build.gradle'

try {
    def servicesJSON = file('google-services.json')
    if (servicesJSON.text) {
        apply plugin: 'com.google.gms.google-services'
    }
} catch(Exception e) {
    logger.info("google-services.json not found, google-services plugin not applied. Push Notifications won't work")
}

内容的提问来源于stack exchange，提问作者Ivan Dzoibo