npm run android 不会启动 Android 应用程序

Question

问题

在忽略错误并按照React Native Navigation 安装中的其余步骤操作后，我能够解决上一个问题。那些警告消失了。

但是，当我运行时npm run android，它构建成功但不启动应用程序

Configure project :app
...
Configure project :react-native-navigation
...
Task :app:installDebug
...
BUILD SUCCESSFUL in 6s

Android 模拟器会转到主屏幕，并且应用程序不会启动。

我尝试过的

• 我尝试过从 android studio 运行/构建/清理和重建。这导致Could not connect to development server我从白色的空白屏幕刷新。

• 我已按照此处的步骤创建资产文件夹并运行此代码

  react-native bundle --platform android --dev false --entry-file index.android.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res
  

---

构建.gradle

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

buildscript {
    ext {
        buildToolsVersion = "28.0.3"
        minSdkVersion = 19
        compileSdkVersion = 28
        targetSdkVersion = 28
        supportLibVersion = "28.0.0"
    }
    repositories {
        google()
        mavenLocal()
        mavenCentral()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.3.0'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
        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://jitpack.io' }
    }
}

应用程序/build.gradle

apply plugin: "com.android.application"

import com.android.build.OutputFile

project.ext.react = [
    entryFile: "index.js"
]

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 rootProject.ext.compileSdkVersion

    defaultConfig {
        applicationId "com.appname"
        minSdkVersion rootProject.ext.minSdkVersion
        targetSdkVersion rootProject.ext.targetSdkVersion
        missingDimensionStrategy "RNN.reactNativeVersion", "reactNative57_5"
        versionCode 1
        versionName "1.0"
        ndk {
            abiFilters "armeabi-v7a", "x86"
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    splits {
        abi {
            reset()
            enable enableSeparateBuildPerCPUArchitecture
            universalApk false  // If true, also generate a universal APK
            include "armeabi-v7a", "x86"
        }
    }
    buildTypes {
        release {
            minifyEnabled enableProguardInReleaseBuilds
            proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
        }
    }
    // 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 fileTree(dir: "libs", include: ["*.jar"])
    implementation "com.android.support:design:28.0.0"
    implementation "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.facebook.react:react-native:+"  // From node_modules
    implementation project(':react-native-navigation')
}

// 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'
}

• 反应本机：“0.57.8”
• 反应本机导航：“^2.7.0”
• 安卓9.0 API 28

Answer 1

我认为您可能必须在运行 npm run android 之前运行 Metro 捆绑程序。

react-native start --reset-cache

这将启动捆绑程序，因此您必须运行

npm run android

在不同的终端窗口，但相同的项目目录中。下面提到这个脚本！我就是这样做的。自 RN 57.2 以来，地铁捆绑器一直存在一些问题，这就是解决办法。与此同时，我已经更新到 RN 57.8 和最新的 RNN，但我仍然这样运行该项目。

我还必须提到，我正在具有 API 26 和 Android Studio 3.3 的模拟器上运行它，通常如果我按照上面所说的方式运行它，它将在模拟器中启动应用程序。

构建脚本

"scripts": {
    "build-android": "cd ./android && ./gradlew app:assembleDebug && ./gradlew installDebug && cd ../",
    "android": "npm run build-android && (adb reverse tcp:8081 tcp:8081 || true) && react-native run-android"
}

编辑

尤其重要的是，您应按照 RNN 团队在此链接下提供的说明在 Android 上运行您的应用程序： RNN 团队在 Android 模拟器或设备上运行您的应用程序的说明。

编辑2

根据请求，需要 API 26，因为这是您的编译 SDK 版本（当前适用于 RNN v2.7.1）以及您的目标 SDK 版本。您可以在 RNN 文档中找到此信息，其链接与上述相同。