错误:MainApplication不是抽象的，并且不覆盖抽象方法

Question

请帮帮忙！！我一直在到处寻找，但没有得到答案

错误:MainApplication不是抽象的，并且不覆盖抽象方法

环境

React Native Navigation version: 7.24.0
React Native version: 0.66.3

android/build.gradle系统

buildscript {
ext {
    minSdkVersion = 21 // Or higher
    compileSdkVersion = 29
    targetSdkVersion = 29
    supportLibVersion = "28.0.0"
    supportVersion = "28.0.0"
    googlePlayServicesLocationVersion = "16.0.0"
    googlePlayServicesVersion = "16.0.0"
    googlePlayServicesVisionVersion = "17.0.2"
    reactNativeVersion = "+"
    kotlinVersion = "1.5.31" // Or any version above 1.3.x
    RNNKotlinVersion = kotlinVersion

  repositories {
        google()
        jcenter()
         mavenLocal()
         mavenCentral()
  }



configurations.all {
    resolutionStrategy.force 'com.google.code.findbugs:jsr305:2.0.1'
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.31"
        classpath 'com.android.tools.build:gradle:3.6.0'
        classpath 'com.google.gms:google-services:4.3.10'

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

allprojects {
    repositories {
        google()
        mavenLocal()
        jcenter()
        maven {
            // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
            url "$rootDir/../node_modules/react-native/android"
        }
         maven {
             url 'https://maven.google.com/'
             name 'Google'
         }
    maven { url 'https://jitpack.io' }
  }
}

  subprojects {
    project.configurations.all {
        resolutionStrategy.eachDependency { details ->
            if (details.requested.group == 'com.android.support'
                    && !details.requested.name.contains('multidex') ) {
                details.useVersion "29.0.0"
            }
            if (details.requested.group == 'com.google.android.gms'
            && !details.requested.name.contains('multidex') && !details.requested.name.contains('play-services-stats')) {
                details.useVersion "17.0.0"
            }
            if (details.requested.group == 'com.google.android.gms'
            && !details.requested.name.contains('multidex') && details.requested.name.contains('play-services-stats')) {
                details.useVersion "+"
            }
        }
    }
}

App/build.gradle

apply plugin: "com.android.application"
    
import com.android.build.OutputFile

/**
 * The react.gradle file registers a task for each build variant (e.g. bundleDebugJsAndAssets
 * and bundleReleaseJsAndAssets).
 * These basically call `react-native bundle` with the correct arguments during the Android build
 * cycle. By default, bundleDebugJsAndAssets is skipped, as in debug/dev mode we prefer to load the
 * bundle directly from the development server. Below you can see all the possible configurations
 * and their defaults. If you decide to add a configuration block, make sure to add it before the
 * `apply from: "../../node_modules/react-native/react.gradle"` line.
 *
 * project.ext.react = [
 *   // the name of the generated asset file containing your JS bundle
 *   bundleAssetName: "index.android.bundle",
 *
 *   // the entry file for bundle generation
 *   entryFile: "index.android.js",
 *
 *   // whether to bundle JS and assets in debug mode
 *   bundleInDebug: false,
 *
 *   // whether to bundle JS and assets in release mode
 *   bundleInRelease: true,
 *
 *   // whether to bundle JS and assets in another build variant (if configured).
 *   // See http://tools.android.com/tech-docs/new-build-system/user-guide#TOC-Build-Variants
 *   // The configuration property can be in the following formats
 *   //         'bundleIn${productFlavor}${buildType}'
 *   //         'bundleIn${buildType}'
 *   // bundleInFreeDebug: true,
 *   // bundleInPaidRelease: true,
 *   // bundleInBeta: true,
 *
 *   // whether to disable dev mode in custom build variants (by default only disabled in release)
 *   // for example: to disable dev mode in the staging build type (if configured)
 *   devDisabledInStaging: true,
 *   // The configuration property can be in the following formats
 *   //         'devDisabledIn${productFlavor}${buildType}'
 *   //         'devDisabledIn${buildType}'
 *
 *   // the root of your project, i.e. where "package.json" lives
 *   root: "../../",
 *
 *   // where to put the JS bundle asset in debug mode
 *   jsBundleDirDebug: "$buildDir/intermediates/assets/debug",
 *
 *   // where to put the JS bundle asset in release mode
 *   jsBundleDirRelease: "$buildDir/intermediates/assets/release",
 *
 *   // where to put drawable resources / React Native assets, e.g. the ones you use via
 *   // require('./image.png')), in debug mode
 *   resourcesDirDebug: "$buildDir/intermediates/res/merged/debug",
 *
 *   // where to put drawable resources / React Native assets, e.g. the ones you use via
 *   // require('./image.png')), in release mode
 *   resourcesDirRelease: "$buildDir/intermediates/res/merged/release",
 *
 *   // by default the gradle tasks are skipped if none of the JS files or assets change; this means
 *   // that we don't look at files in android/ or ios/ to determine whether the tasks are up to
 *   // date; if you have any other folders that you want to ignore for performance reasons (gradle
 *   // indexes the entire tree), add them here. Alternatively, if you have JS files in android/
 *   // for example, you might want to remove it from here.
 *   inputExcludes: ["android/**", "ios/**"],
 *
 *   // override which node gets called and with what additional arguments
 *   nodeExecutableAndArgs: ["node"],
 *
 *   // supply additional arguments to the packager
 *   extraPackagerArgs: []
 * ]
 */

apply from: "../../node_modules/react-native/react.gradle"

/**
 * Set this to true to create two separate APKs instead of one:
 *   - An APK that only works on ARM devices
 *   - An APK that only works on x86 devices
 * The advantage is the size of the APK is reduced by about 4MB.
 * Upload all the APKs to the Play Store and people will download
 * the correct one based on the CPU architecture of their device.
 */
def enableSeparateBuildPerCPUArchitecture = false

/**
 * Run Proguard to shrink the Java bytecode in release builds.
 */
def enableProguardInReleaseBuilds = false

android {
    compileSdkVersion 31
    buildToolsVersion "29.0.3"

    defaultConfig {
        applicationId "com.prasiam.trader"
        minSdkVersion 21
        targetSdkVersion 31
        versionCode 4
        versionName "1.4"
        multiDexEnabled = true
        ndk {
            abiFilters "armeabi-v7a", "x86"
        }
    }
    repositories {
    jcenter()
    google() // Google's Maven repository
    maven {
        url "https://maven.google.com"
    }
}
    signingConfigs {
        release {
            if (project.hasProperty('MYAPP_RELEASE_STORE_FILE')) {
                storeFile file(MYAPP_RELEASE_STORE_FILE)
                storePassword MYAPP_RELEASE_STORE_PASSWORD
                keyAlias MYAPP_RELEASE_KEY_ALIAS
                keyPassword MYAPP_RELEASE_KEY_PASSWORD
            }
        }
    }
    splits {
        abi {
            reset()
            enable enableSeparateBuildPerCPUArchitecture
            universalApk false  // If true, also generate a universal APK
            include "armeabi-v7a", "x86"
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    buildTypes {
        release {
            proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
            signingConfig signingConfigs.release
        }
    }
    // applicationVariants are e.g. debug, release
    applicationVariants.all { variant ->
        variant.outputs.each { output ->
            // For each separate APK per architecture, set a unique version code as described here:
            // http://tools.android.com/tech-docs/new-build-system/user-guide/apk-splits
            def versionCodes = ["armeabi-v7a":1, "x86":2]
            def abi = output.getFilter(OutputFile.ABI)
            if (abi != null) {  // null for the universal-debug, universal-release variants
                output.versionCodeOverride =
                        versionCodes.get(abi) * 1048576 + defaultConfig.versionCode
            }           
        }
    }
    configurations.all {
    resolutionStrategy.eachDependency { DependencyResolveDetails details ->
        def requested = details.requested
        if (requested.group == 'com.android.support' && requested.name != 'multidex') {
            details.useVersion "${rootProject.ext.supportLibVersion}"
        }
    }
}
}

dependencies {
    implementation(project(':react-native-firebase:')) {
        transitive = false
    }

    // Firebase dependencies
    implementation platform('com.google.firebase:firebase-bom:29.0.0')
    implementation 'com.google.android.gms:play-services-gcm:17.0.0'
    implementation "com.google.android.gms:play-services-base:17.6.0"
    implementation "com.google.android.gms:play-services-tasks:17.2.1"
    implementation "com.google.android.gms:play-services-afs-native:19.0.1"
    implementation "com.google.firebase:firebase-core"
    implementation "com.google.firebase:firebase-messaging"
    implementation "com.google.firebase:firebase-analytics"
    implementation "com.google.firebase:firebase-auth"
    implementation "androidx.annotation:annotation:1.0.2"
    implementation "androidx.appcompat:appcompat:1.0.0-alpha3"
    implementation fileTree(dir: "libs", include: ["*.jar"])
    
    implementation 'com.android.support:design:25.4.0'
    implementation "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.facebook.react:react-native:+"  // From node_modules
    implementation project(':react-native-vector-icons')
    implementation project(':react-native-device-info')
    implementation project(':react-native-navigation')
    
    testImplementation ("org.robolectric:robolectric:4.7.2"){
        exclude group: 'org.apache.maven', module: 'maven-artifact'
        exclude group: 'org.apache.maven', module: 'maven-artifact-manager'
        exclude group: 'org.apache.maven', module: 'maven-model'
        exclude group: 'org.apache.maven', module: 'maven-plugin-registry'
        exclude group: 'org.apache.maven', module: 'maven-profile'
        exclude group: 'org.apache.maven', module: 'maven-project'
        exclude group: 'org.apache.maven', module: 'maven-settings'
        exclude group: 'org.apache.maven', module: 'maven-error-diagnostics'
        exclude group: "org.apache.maven.wagon"
}

}

// Run this once to be able to run the application with BUCK
// puts all compile dependencies into folder libs for BUCK to use
task copyDownloadableDepsToLibs(type: Copy) {
    from configurations.compile
    into 'libs'
}

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

我的主应用程序

import android.app.Application;
import androidx.annotation.Nullable;
import com.reactnativenavigation.react.NavigationReactNativeHost;
import com.reactnativenavigation.NavigationActivity;
import com.reactnativenavigation.NavigationApplication;
import com.facebook.react.ReactApplication;
import io.invertase.firebase.RNFirebasePackage;
import io.invertase.firebase.messaging.RNFirebaseMessagingPackage;
import io.invertase.firebase.notifications.RNFirebaseNotificationsPackage;
import com.oblador.vectoricons.VectorIconsPackage;
import com.learnium.RNDeviceInfo.RNDeviceInfo;
import com.facebook.react.ReactApplication;
import com.facebook.react.ReactNativeHost;
import com.facebook.react.ReactPackage;
import com.facebook.react.shell.MainReactPackage;
import com.facebook.soloader.SoLoader;

import java.util.Arrays;
import java.util.List;

public class MainApplication extends NavigationApplication {

  @Override
  public String getJSMainModuleName() {
    return "index";
  }

  @Override
  public boolean isDebug() {
    // Make sure you are using BuildConfig from your own application
    return BuildConfig.DEBUG;
  }

  protected List<ReactPackage> getPackages() {
    // Add additional packages you require here
    // No need to add RnnPackage and MainReactPackage
    return Arrays.<ReactPackage>asList(
      new RNFirebasePackage(),
      new RNFirebaseMessagingPackage(),
      new RNFirebaseNotificationsPackage(),
      new VectorIconsPackage(),
      new RNDeviceInfo()
    );
  }

  @Override
  public List<ReactPackage> createAdditionalReactPackages() {
    return getPackages();
  }
}

错误：

任务：app:compileDebugJavaWithJavac C:\Users\user\Downloads\Scripts\kantongin mobile\trader\android\app\src\main\java\com\prasiam\trader\MainApplication。java:23:error:MainApplication不是abtr-act，并且不重写ReactApplication中的抽象方法getReactNativeHost（）

公共类MainApplication扩展NavigationApplication{^C：\User\user\xxx\xxx\xxx\android\app\src\main\java\com\prasiam\trader\MainApplication.java:25：错误：方法没有覆盖或实现来自超型的方法@Override^C：\用户\用户\xxx\xxx\xxx\trader\android\app\src\main\java\com\prasiam\trader\MainApplication.java:30：错误：方法没有覆盖或实现来自超型的方法@Override^C：\用户\用户\xxx\xxx\xxx\xxx\xxx\xxx\android\app\src\main\java\com\prasiam\trader\MainApplication.java:48：错误：方法没有覆盖或实现来自超型的方法@Override^4错误

任务：应用程序：compileDebugJavaWithJavac失败

失败：生成失败，出现异常。

• 出了什么问题：任务“：app：compileDebugJava与Javac”的执行失败。

编译失败；有关详细信息，请参见编译器错误输出。

• 尝试：使用--stacktrace选项运行以获取堆栈跟踪。使用--info或--debug选项运行以获取更多日志输出。使用--scan运行以获取完整信息

提前感谢

Answer 1

对于现在正在研究这个问题的任何人来说，只需添加getReactNativeHost（）方法的实现即可。我遇到这个问题是因为我在升级react native时错过了它。

请参阅 MainApp.java仔细检查您的更改/文件（确保更改版本以匹配您的项目）：https://react-native-community.github.io/upgrade-helper/?from=0.64.3