使反应本机运行时出现问题

Question

要安装的信息源： - https://facebook.github.io/react-native/docs/getting-started.html

此外，我还添加了环境变量。

然后使用了这些命令，它完美运行：

npm 启动 npm 运行安卓

然后当我运行以下命令时：

React-native run-android

它显示了这个error：显示错误堆栈的图像

D:ProjectsReact-NativeAwesomeProject>react-native run-android
    Scanning 768 folders for symlinks in D:ProjectsReact-NativeAwesomeProjectnod
    e_modules (31ms)
    Starting JS server...
    Building and installing the app on the device (cd android && gradlew.bat install
    Debug)...
    FAILURE: Build failed with an exception.
    * Where:
    Build file 'D:ProjectsReact-NativeAwesomeProjectandroidappbuild.gradle' li
    ne: 1
    * What went wrong:
    A problem occurred evaluating project ':app'.
    > java.lang.UnsupportedClassVersionError: com/android/build/gradle/AppPlugin : U
    nsupported major.minor version 52.0
    * Try:
    Run with --stacktrace option to get the stack trace. Run with --info or --debug
    option to get more log output.
    BUILD FAILED
    Total time: 3.124 secs
    Could not install the app on the device, read the error above for details.
    Make sure you have an Android emulator running or a device connected and have
    set up your Android development environment:
    https://facebook.github.io/react-native/docs/android-setup.html
    events.js:182
          throw er; // Unhandled 'error' event
          ^
    Error: spawn cmd.exe ENOENT
        at _errnoException (util.js:1019:11)
        at Process.ChildProcess._handle.onexit (internal/child_process.js:192:19)
        at onErrorNT (internal/child_process.js:374:16)
        at _combinedTickCallback (internal/process/next_tick.js:138:11)
        at process._tickCallback (internal/process/next_tick.js:180:9)

---

构建分级

        buildscript {
        repositories {
            jcenter()
        }
        dependencies {
            classpath 'com.android.tools.build:gradle:2.2.3'
            // 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"
            }
        }
    }

Answer 1

显然你的build.gradle文件中有一个错误。

在不查看文件的情况下，我想它可能与最低 android 版本或类似的东西有关。

此 gradle 文件包含构建您的 android 应用程序的所有信息，因此如果它包含错误，您会收到"失败：构建失败，出现异常"。

Answer 2

我已经通过添加适当的环境变量路径解决了这个问题。 请参阅随附的屏幕截图。

C：\Windows\System32*WindowsPowerShell\v1.0*;
C：\Users\gyrix**AppData\Roamingpm**;
C：\Users\gyrix**AppData\Local\Yarn\bin**;
D：\Android\sdk1**platform-tools**;
E：\android-sdk**build-tools\25.0.2**;
D：\Android**sdk1**;
D：\Android\sdk1**tools**;
C：\Program Files**Java\jdk1.8.0_144\bin**;

注意：请以粗体指定文件夹的路径，它可能因系统而异。 enter code here