RN 集成到Android步骤

RN虽可以独立打成apk包作为独立应用，但目前更多情形是将其嵌入Native中。本文记录如何将RN集成到android(需要了解一点android知识噢)

1、新建Android Studio 工程为AndroidRnDemo

• 1、在根目录AndroidRnDemo下执行npm init 建立package.json并安装react react-native的依赖

npm init
npm install --save react react-native

• 2、修改package.json的scripts字段，新增start

"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "node node_modules/react-native/local-cli/cli.js start"
},

2、将ReactNative添加到Android项目

• 1、配置app目录下的build.gradle：

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    api "com.facebook.react:react-native:+"       //将RN相关库添加至Android依赖
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

• 2、配置根目录下的build.gradle：

allprojects {
    repositories {
        google()
        maven {
            url "$rootDir/node_modules/react-native/android"
        }
        jcenter()

    }
}

• 3、配置Android-Manifest.xml，添加权限

/**设置调试 的权限**/
<uses-permission android:name="android.permission.INTERNET" />     // 网络权限
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-permission android:name="android.permission.SYSTEM_OVERLAY_WINDOW" />
// 添加debug模式Activity(正式打包注释掉就好了,activity要放在application内)
<activity android:name="com.facebook.react.devsupport.DevSettingsActivity"/>

3、添加RN界面

• 1、在项目根目录下新建index.js

import React from 'react';
import {AppRegistry, StyleSheet, Text, View} from 'react-native';
class HelloWorld extends React.Component {
  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.hello}>Hello, World</Text>
      </View>
    );
  }
}
var styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
  },
  hello: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
});
AppRegistry.registerComponent('AndroidRnDemoApp', () => HelloWorld);

• 2、新建一个Activity作为RN界面的容器，命名为RNActivity

package com.example.com.androidrndemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;


import com.facebook.react.ReactInstanceManager;
import com.facebook.react.ReactRootView;
import com.facebook.react.common.LifecycleState;
import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
import com.facebook.react.shell.MainReactPackage;

public class RNActivity 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")
                .setJSMainModulePath("index")
                .addPackage(new MainReactPackage())
                .setUseDeveloperSupport(BuildConfig.DEBUG)
                .setInitialLifecycleState(LifecycleState.RESUMED)
                .build();
        //这里的AndroidRnDemoApp必须对应“index.js”中的“AppRegistry.registerComponent()”的第一个参数
        mReactRootView.startReactApplication(mReactInstanceManager, "AndroidRnDemoApp", null);
        //加载ReactRootView到布局中
        setContentView(mReactRootView);
    }
    @Override
    public void invokeDefaultOnBackPressed() {
        super.onBackPressed();
    }
    /**
     * ReactInstanceManager生命周期同activity
     */
    @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 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);
    }
}

• 3、在MainActivity中添加Intent跳转到RNActivity逻辑（button的点击触发）

package com.example.com.androidrndemo;

import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.AppCompatButton;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button=(Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v){
                Intent intent = new Intent(MainActivity.this,RNActivity.class);    //沟通两个activity的桥梁
                startActivity(intent);
            }
        });
    }
}

// layout_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.com.androidrndemo.MainActivity">

    <Button android:id='@+id/button'
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:text="go RN Page"></Button>

</android.support.constraint.ConstraintLayout>

• 4、在Android-Manifest.xml中注册activity

<activity
  android:name=".RNActivity"
  android:theme="@style/Theme.AppCompat.Light.NoActionBar">
</activity>

4、打包、编译、安装、运行

4.1 本地开发

• 1、将RN编译到Android，并在模拟器上安装debug版apk包

gradlew build
gradlew installDebug

• 2、RN的调试、热更新
  先启动Package提供服务

//先开启本地react native服务
npm start

然后在模拟器上打开应用，当点击button时，进入RN界面，此时需要设置本地ip和端口
window上“ctrl+M” 打开dev settings设置界面：

设置dev settings

• 3、开启热更新、实时刷新功能

  
  image.png
  

  注意：开启chrome远程调试时有时需先用google浏览器访问：你的ip:8081。
  远程调试看不到RN界面，只能打断点和输出一些信息

  
  远程调试
  若是在真机上调试需执行：adb reverse tcp:8081 tcp:8081

4.2 、打包发布

• 1 、在app/src/main下新建assets目录，执行以下命令打包

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

• 2、将RN编译进Android

gradlew assembleRelease

5、遇到过的崩溃问题

• 如果出现32 64等.so包的报错

// 1.在build.gradle加入
android {
  ...
    defaultConfig {
            ...
        ndk {
            abiFilters "armeabi", "armeabi-v7a", "x86", "mips"
        }

        packagingOptions {
            exclude "lib/arm64-v8a/librealm-jni.so"
        }
    }
// 2.在gradle.properties尾部加入
Android.useDeprecatedNdk=true