Question

我创建了一个react-native项目并在android studio中将其打开，但是出现了这些错误

package com.project1;

import android.app.Application;
import com.facebook.react.ReactApplication;     //cannot find
import com.facebook.react.ReactNativeHost;      //cannot find
import com.facebook.react.ReactPackage;         //cannot find
import com.facebook.react.shell.MainReactPackage;   //cannot find
import com.facebook.soloader.SoLoader;             //cannot find

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

public class MainApplication extends Application implements ReactApplication {

 private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
@Override
public boolean getUseDeveloperSupport() {
  return BuildConfig.DEBUG;
}

@Override
protected List<ReactPackage> getPackages() {
  return Arrays.<ReactPackage>asList(
      new MainReactPackage()
  );
}

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

@Override
public ReactNativeHost getReactNativeHost() {
return mReactNativeHost;
}

@Override
public void onCreate() {
super.onCreate();
SoLoader.init(this, /* native exopackage */ false);
}
}

这里所有的react类都抛出错误，android studio根本找不到任何东西。

我还阅读了stackoverflow和github上的所有文章，但似乎什么也没有。我现在很沮丧，因为经过4天在Windows中使用0.56.0遇到的种种麻烦之后，我让这个项目开始运行。我不得不切换到ubuntu并不得不使用0.55.4，然后我启动了该项目，但现在却遇到了这些错误。

这也是我的项目级别的build.gradle文件

buildscript {
repositories {
    jcenter()
    google()
}
dependencies {
    classpath 'com.android.tools.build:gradle:3.1.4'

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

}

allprojects {
repositories {
    mavenLocal()
    jcenter()
    maven {
        // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
        url "$rootDir/../node_modules/react-native/android"

    }
    google()

}
}

这是应用程序级别的build.gradle文件：

apply plugin: "com.android.application"

import com.android.build.OutputFile

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

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


def enableSeparateBuildPerCPUArchitecture = false


def enableProguardInReleaseBuilds = false

android {
compileSdkVersion 27
//buildToolsVersion '27.0.2'

defaultConfig {
    applicationId "com.project1"
    minSdkVersion 16
    targetSdkVersion 27
    versionCode 1
    versionName "1.0"
    ndk {
        abiFilters "armeabi-v7a", "x86"
    }
}
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
        }
    }
}

}

dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation 'com.android.support:appcompat-v7:27.0.2'
implementation 'com.android.support:support-v4:27.0.2'
implementation 'com.android.support:design:27.0.2'
implementation 'com.android.support:cardview-v7:27.0.2'
implementation 'com.facebook.react:react-native:0.55.4'

}


task copyDownloadableDepsToLibs(type: Copy) {
from configurations.compile
into 'libs'
}

这是android studio的屏幕截图

Answer 1

首先，当您遇到react-native@0.56.0问题时，是的，这是react-native库中的一个错误，因为它与某些其他依赖项不兼容。我已经回答了这个问题here.

现在，如果您遇到以下错误，即android studio找不到反应库，则发生这种情况的原因有两个，我知道。

您要通过复制/粘贴在其他地方找到的 project1 / android 来打开android项目，然后从android studio中打开。
您未与Internet连接，因为它在构建之前会从Internet加载一些东西。

第二件事，如果要在android studio中打开react项目，则只能在需要运行 Metro Bundler 的情况下从那里构建它，以运行您的应用。要运行它，请在react-native项目内的cmd中使用 react-native start 命令。

我能够在android studio中成功打开我的react-native项目并在那里构建，但是如果 Metro Bundler 已运行并提供了其屏幕截图，则能够运行。

检查以上两点后，您仍然会遇到错误，请尝试

从项目中删除 node_modules
然后运行 npm install --save
然后运行 react-native run-android 来检查应用程序是否在模拟器中运行。

尝试以上操作，让我知道您是否仍然遇到错误。

Gradle（Module：app）：-

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: []
 * ]
 */

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
    buildToolsVersion rootProject.ext.buildToolsVersion

    defaultConfig {
        applicationId "com.profileui"
        minSdkVersion rootProject.ext.minSdkVersion
        targetSdkVersion rootProject.ext.targetSdkVersion
        versionCode 1
        versionName "1.0"
        ndk {
            abiFilters "armeabi-v7a", "x86"
        }
    }
    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
            }
        }
    }
}

dependencies {
    compile fileTree(dir: "libs", include: ["*.jar"])
    compile "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
    compile "com.facebook.react:react-native:+"  // From node_modules
}

// 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'
}

Gradle（项目：project_name）

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

buildscript {
    repositories {
        jcenter()
        maven {
            url 'https://maven.google.com/'
            name 'Google'
        }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'

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

allprojects {
    repositories {
        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'
        }
    }
}

ext {
    buildToolsVersion = "26.0.3"
    minSdkVersion = 16
    compileSdkVersion = 26
    targetSdkVersion = 26
    supportLibVersion = "26.1.0"
}

找不到任何反应班

1 个答案: