java - react native : error: cannot find symbol after upgrade

Question

您好，在导入我的 React Native 项目 expo 并升级 React 后，我​​遇到了以下问题。

C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:5: error: cannot find symbol import com.facebook.react.ReactApplication; ^ symbol: class ReactApplication location: package com.facebook.react C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:13: error: cannot find symbol import com.facebook.react.ReactNativeHost; ^ symbol: class ReactNativeHost location: package com.facebook.react C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:21: error: cannot find symbol public class MainApplication extends Application implements ReactApplication { ^ symbol: class ReactApplication C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:23: error: cannot find symbol private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) { ^ symbol: class ReactNativeHost location: class MainApplication C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:40: error: cannot find symbol public ReactNativeHost getReactNativeHost() { ^ symbol: class ReactNativeHost location: class MainApplication C:\Users\user\gramic\android\app\src\main\java\com\shop\MainActivity.java:5: error: MainActivity is not abstract and does not override abstract method getPackages() in ReactActivity public class MainActivity extends ReactActivity { ^ C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:23: error: cannot find symbol private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) { ^ symbol: class ReactNativeHost location: class MainApplication C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:39: error: method does not override or implement a method from a supertype @Override ^

    package com.shop;

import android.app.Application;

import com.facebook.react.ReactApplication;
import com.oblador.vectoricons.VectorIconsPackage;
import com.corbt.keepawake.KCKeepAwakePackage;
import com.oblador.vectoricons.VectorIconsPackage;
import com.github.yamill.orientation.OrientationPackage;
import com.BV.LinearGradient.LinearGradientPackage;
import com.brentvatne.react.ReactVideoPackage;

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 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(),
            new VectorIconsPackage(),
            new VectorIconsPackage(),
            new KCKeepAwakePackage(),
            new VectorIconsPackage(),
            new OrientationPackage(),
            new LinearGradientPackage(),
            new ReactVideoPackage()

      );
    }
  };

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

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

Answer 1

首先:使用yarn或npm安装所有依赖；

其次:使用下面的代码链接iOS和Android原生代码上的原生依赖；

react-native link

第三:会出现这个错误是因为你的RN版本和Android的build.gradle版本不一样。当您创建一个 react-native 应用程序时，它可能会创建像这样的 android 应用程序:

android/app/build.gradle

implementation "com.facebook.react:react-native:+"

因此，检查您的 node_modules 文件夹，查找 react-native 文件夹并查找带有数字的文件夹，该数字是 react-native 版本。对我来说，它是 0.58.3 然后更新 android/app/build.gradle:

implementation "com.facebook.react:react-native:0.58.3"

这就是全部。