前言

将一个现有工程接入rn开放，中间会有不少坑，今天记录下步骤和遇到的几个坑和解决办法

1 :用AndroidStudio创建一个工程，我的工程名称：AndroidInstallRn

2:打开命令行终端，进入AndroidInstallRn工程里面

3：输入命令，

1: npm init
坑：Press ^C at any time to quit. 出现这一行以后开始输入一些配置信息，name不能大写。

20161014091825866.png

2:npm install --save react react-native
坑：执行的时候报错
npm WARN [email protected] requires a peer of [email protected] but none was installed.
解决办法：执行 npm i -S [email protected] 找到项目中package.json文件，确认react是刚才安装版本就不用管了

"dependencies": {
    "react": "^16.0.0-alpha.6",
    "react-native": "^0.43.4"
  }

3：在package.json的scripts中加入字段

"start": "node node_modules/react-native/local-cli/cli.js start"

这时候package.json应该张这样

{
  "name": "androidinstallrn",
  "version": "1.0.0",
  "description": "rn test",
  "main": "index.android.js",
  "scripts": {
    "start": "node node_modules/react-native/local-cli/cli.js start"
  },
  "keywords": [
    "test",
    "rn"
  ],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "react": "^16.0.0-alpha.6",
    "react-native": "^0.43.4"
  }
}

4：继续在命令行执行

curl -o .flowconfig https://raw.githubusercontent.com/facebook/react-native/master/.flowconfig

5:把最简单的rn代码复制到index.android.js中

 'use strict';

import React from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  View
} from 'react-native';

class HelloWorld extends React.Component {
  render() {
    return (
      
        Hello, World
      
    )
  }
}
var styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
  },
  hello: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
});

AppRegistry.registerComponent('HelloWorld', () => HelloWorld);

4:修改app工程

1：在你的app中 build.gradle 文件中添加 React Native 依赖:

dependencies {
     ...
     compile "com.facebook.react:react-native:+" // From node_modules.
 }

你想要指定构建时的 React Native 版本，请用 npm 已下载的本地 React Native 的版本号替换 +
2:在项目的 build.gradle 文件中为 React Native 添加一个 maven 依赖的入口，必须写在 "allprojects" 代码块中:

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

确保依赖路径的正确！以免在 Android Studio 运行Gradle同步构建时抛出 “Failed to resolve: com.facebook.react:react-native:0.x.x" 异常。
3:接着，在 AndroidManifest.xml 清单文件中声明权限:

4：修改MainActivity

public class MainActivity extends AppCompatActivity implements DefaultHardwareBackBtnHandler {
    private ReactRootView mReactRootView;
    private ReactInstanceManager mReactInstanceManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mReactRootView = new ReactRootView(this);
        mReactInstanceManager = ReactInstanceManager.builder()
                .setApplication(getApplication())
                .setBundleAssetName("index.android.bundle")
                .setJSMainModuleName("index.android")
                .addPackage(new MainReactPackage())
                .setUseDeveloperSupport(BuildConfig.DEBUG)
                .setInitialLifecycleState(LifecycleState.RESUMED)
                .build();

        // 注意这里的HelloWorld必须对应“index.android.js”中的
        // “AppRegistry.registerComponent()”的第一个参数
        mReactRootView.startReactApplication(mReactInstanceManager, "HelloWorld", null);

        setContentView(mReactRootView);
    }
    @Override
    protected void onPause() {
        super.onPause();

        if (mReactInstanceManager != null) {
            mReactInstanceManager.onHostPause(this);
        }
    }

    @Override
    protected void onResume() {
        super.onResume();

        if (mReactInstanceManager != null) {
            mReactInstanceManager.onHostResume(this,this);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        if (mReactInstanceManager != null) {
            mReactInstanceManager.onHostDestroy(this);
        }
    }

    @Override
    public void invokeDefaultOnBackPressed() {
        super.onBackPressed();
    }
    @Override
    public void onBackPressed() {
        if (mReactInstanceManager != null) {
            mReactInstanceManager.onBackPressed();
        } else {
            super.onBackPressed();
        }
    }
    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_MENU && mReactInstanceManager != null) {
            mReactInstanceManager.showDevOptionsDialog();
            return true;
        }
        return super.onKeyUp(keyCode, event);
    }
}

5:到这基本完成，在命令行运行

npm start

启动rn服务
坑：这个时候运行npm start可能会报错：

 Loading dependency graph... ERROR  Packager can't listen on port 8081
Most likely another process is already using this port
Run the following command to find out which process:

   lsof -i :8081 

Then, you can either shut down the other process:

   kill -9  

or run packager on different port.

See http://facebook.github.io/react-native/docs/troubleshooting.html
for common problems and solutions.

这是8081端口被占用了，rn默认启动端口是8081解决办法

$  lsof -i :8081 

$ kill - 9 <进程id>

6：启动成功。在studio上运用app
坑 app报错

FATAL EXCEPTION: AsyncTask #1
 Process: com.example.wuxiaoyong.androidinstallrn, PID: 3121                         java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:330)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:255)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:776)
Caused by: java.lang.UnsatisfiedLinkError: could find DSO to load: libreactnativejni.so
at com.facebook.soloader.SoLoader.loadLibraryBySoName(SoLoader.java:213)
at com.facebook.soloader.SoLoader.loadLibrary(SoLoader.java:178)
at com.facebook.react.bridge.JSCJavaScriptExecutor.(JSCJavaScriptExecutor.java:25)
at com.facebook.react.bridge.JSCJavaScriptExecutor$Factory.create(JSCJavaScriptExecutor.java:20)
at com.facebook.react.ReactInstanceManagerImpl$ReactContextInitAsyncTask.doInBackground(ReactInstanceManagerImpl.java:183)
at com.facebook.react.ReactInstanceManagerImpl$ReactContextInitAsyncTask.doInBackground(ReactInstanceManagerImpl.java:169)
at android.os.AsyncTask$2.call(AsyncTask.java:316)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:255) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
at java.lang.Thread.run(Thread.java:776)

问题原因：
Android不能同时加载32和64位本机库。如果您至少有一个依赖库使用ARM64支持编译的扩展，而另外一些依赖库仅支持ARM32，就会出现问题。系统将检测ARM64依赖关系，加载它，然后拒绝加载仅ARM32的so库，就可能导致应用程序崩溃。
项目中只有libimagepipeline.so有arm64-v8a支持编译的扩展，Smartisan M1手机发现有64位的本机库，就不会再去加载32位的本机库，所以在Native Libraries installed区就只能看到libimagepipeline.so一个so库。也因此会报我们开篇提到的两个缺省so库的Error，也因此回复了为什么只有一个so库的问题。
解决办法：在你的app中 build.gradle 中加入

defaultConfig {
       ndk{
            abiFilters "armeabi-v7a","x86"
        }
        packagingOptions {
            exclude "lib/arm64-v8a/libimagepipeline.so"
        }
    }

OK 解决这个之后，又一个坑，又一个报错，真是一步一个坑

Caused by: java.lang.IllegalAccessError: Method 'void android.support.v4.net.ConnectivityManagerCompat.()' is inaccessible to class 'com.facebook.react.modules.netinfo.NetInfoModule' (declaration of 'com.facebook.react.modules.netinfo.NetInfoModule' appears in /data/data/com.example.wuxiaoyong.androidinstallrn/files/instant-run/dex/slice-com.facebook.react-react-native-0.20.1_241a9e4c0e7198091bd2bc50912d161a24710fbf-classes.dex)
at com.facebook.react.modules.netinfo.NetInfoModule.(NetInfoModule.java:55)
at com.facebook.react.shell.MainReactPackage.createNativeModules(MainReactPackage.java:67)
at com.facebook.react.ReactInstanceManagerImpl.processPackage(ReactInstanceManagerImpl.java:793)
at com.facebook.react.ReactInstanceManagerImpl.createReactContext(ReactInstanceManagerImpl.java:730)
at com.facebook.react.ReactInstanceManagerImpl.access$600(ReactInstanceManagerImpl.java:91)
at com.facebook.react.ReactInstanceManagerImpl$ReactContextInitAsyncTask.doInBackground(ReactInstanceManagerImpl.java:184)
at com.facebook.react.ReactInstanceManagerImpl$ReactContextInitAsyncTask.doInBackground(ReactInstanceManagerImpl.java:169)
at android.os.AsyncTask$2.call(AsyncTask.java:316)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:255) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
at java.lang.Thread.run(Thread.java:776)

问题原因：还记得我们上面再项目build.gradle中的配置吗？

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

这个是我们按照官方文档写的，但是因为$rootDir/本身已经是跟目录了，在"../"就会找不到。我们把"../"去掉

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

ok
这个时候，如果是红屏等连不上服务器等，自己去查看解决方案。
如果手机能连上服务器，就会运用成功了

拓展

多个activity引用不同的js文件

这是一个activity绑定的index.android.js文件的布局，如果我们想在多个activity绑定不同的js文件界面怎么做?
1：新建js文件：

'use strict';

import React from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  View
} from 'react-native';

export default class MyHelloWorld extends React.Component {
  render() {
    return (
      
        Hello, sssssssss
      
    )
  }
}
var styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
  },
  hello: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
});

AppRegistry.registerComponent('MyHelloWorld', () => MyHelloWorld);

然后在index.android.js中引入

import MyHelloWorld from './android_a';

在activity引用：

 mReactRootView.startReactApplication(mReactInstanceManager, "MyHelloWorld", null);

大功告成。
坑：必现在index.android.js中import，然后这个类才会被调用，

AppRegistry.registerComponent('MyHelloWorld', () => MyHelloWorld);

注册才会执行，否则会报错："MyHelloWorld"找不到

同一个界面包含原生文件和RN文件

直接把ReactRootView当Android普通view使用。在绑定的xml中写

在activity中找到这个组件并绑定界面

mReactRootView = (ReactRootView) findViewById(R.id.rn_view)
mReactRootView.startReactApplication(mReactInstanceManager, "HelloWorld", null);

ok 大功告成。
下一篇：Android和RN的交互

Android现有工程接入RN开发

前言