React Native 热更新实现

来源：互联网发布：mysql insert 编辑：程序博客网时间：2024/05/18 05:38

我们先来看看React Native 动态更新实际效果：http://www.tuicool.com/articles/MRjumqI

React Native 热更新实现APK

我们知道, React Native所有的js文件都打包在一个jsbundle文件中，发布时也是打包到app里面,一般是放到asset目录.

如是猜想是不是可以从远程下载jsbundle文件覆盖asset的jsbundle. 查资料发现asset目录是只读的,该想法行不通.

在看React Native 启动入口时,看到通过是setBundleAssetName指定 asset文件的, 查看方法实现:

public ReactInstanceManager.Builder setBundleAssetName(String bundleAssetName) {    return this.setJSBundleFile(bundleAssetName == null?null:"assets://" + bundleAssetName);}

发现调用了setJSBundleFile方法, 而且该方法是public的, 也就是可以通过这个方法指定的jsbundle文件

public ReactInstanceManager.Builder setJSBundleFile(String jsBundleFile) {    this.mJSBundleFile = jsBundleFile;    this.mJSBundleLoader = null;    return this;}

可以设置了jsbundle文件, 那我们就可以把jsbundle文件放到sdcard, 经过测试发现, 确实可以读取sdcard jsbundle.

sdcar的文件开业读取了,那我们就可以把文件放到远程服务器, 启动后下载远程jsbundle文件到sdcard. 大概思路如下:

我们打好包jsbundle文件放到远程服务器
启动React Native, 检查sdcard是否有jsbundle文件, 如果没有调用setBundleAssetName加载asset目录的jsbundle, 同时启动线程下载远程jsbundle文件到sdcard目录.
待下次启动时, sdcard是有jsbundle文件的, 加载的就是最新的jsbundle文件.

实现代码如下:

public static final String JS_BUNDLE_REACT_UPDATE_PATH = Environment.getExternalStorageDirectory().toString() + File.separator + "react_native_update/debug.android.bundle";private void iniReactRootView(boolean isRelease) {        ReactInstanceManager.Builder builder = ReactInstanceManager.builder()                .setApplication(getApplication())                .setJSMainModuleName("debug.android.bundle")                .addPackage(new MainReactPackage())                .addPackage(new Package())                .setInitialLifecycleState(LifecycleState.RESUMED);        File file = new File(JS_BUNDLE_LOCAL_PATH);        if (isRelease && file != null && file.exists()) {            builder.setJSBundleFile(JS_BUNDLE_LOCAL_PATH);            Log.i(TAG, "load bundle from local cache");        } else {            builder.setBundleAssetName(JS_BUNDLE_LOCAL_FILE);            Log.i(TAG, "load bundle from asset");            updateJSBundle();        }        mReactRootView = new ReactRootView(this);        mReactInstanceManager = builder.build();        mReactRootView.startReactApplication(mReactInstanceManager, "SmartReactApp", null);        setContentView(mReactRootView);}// 从远程服务器下载新的jsbundle文件private void updateJSBundle() {        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(JS_BUNDLE_REMOTE_URL));        request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);        request.setDestinationUri(Uri.parse("file://" + JS_BUNDLE_LOCAL_PATH));        DownloadManager dm = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);        mDownloadId = dm.enqueue(request);        Log.i(TAG, "start download remote js bundle file");}

经过测试发现, 确实可以实现动态更新, 但要下次启动才能看到最新的效果, 那有没有办法实现立即看到更新效果呢?

通过查看React Native 源码和查阅资料是可以实现的, 具体实现如下:

为了在运行中重新加载bundle文件，查看ReactInstanceManager的源码，找到如下方法：

private void recreateReactContextInBackground(JavaScriptExecutor jsExecutor, JSBundleLoader jsBundleLoader) {    UiThreadUtil.assertOnUiThread();    ReactContextInitParams initParams = new ReactContextInitParams(jsExecutor, jsBundleLoader);    if (!mIsContextInitAsyncTaskRunning) {      // No background task to create react context is currently running, create and execute one.      ReactContextInitAsyncTask initTask = new ReactContextInitAsyncTask();      initTask.execute(initParams);      mIsContextInitAsyncTaskRunning = true;    } else {      // Background task is currently running, queue up most recent init params to recreate context      // once task completes.      mPendingReactContextInitParams = initParams;    }}

虽然这个方法是private的，但是可以通过反射调用,下面是0.29版本的实现(上面React-Native-Remote-Update项目实现React Native版本旧了,直接拷贝反射参数有问题)

private void onJSBundleLoadedFromServer() {        File file = new File(JS_BUNDLE_LOCAL_PATH);        if (file == null || !file.exists()) {            Log.i(TAG, "js bundle file download error, check URL or network state");            return;        }        Log.i(TAG, "js bundle file file success, reload js bundle");        Toast.makeText(UpdateReactActivity.this, "download bundle complete", Toast.LENGTH_SHORT).show();        try {            Class<?> RIManagerClazz = mReactInstanceManager.getClass();            Field f = RIManagerClazz.getDeclaredField("mJSCConfig");            f.setAccessible(true);            JSCConfig jscConfig = (JSCConfig)f.get(mReactInstanceManager);            Method method = RIManagerClazz.getDeclaredMethod("recreateReactContextInBackground",                    com.facebook.react.cxxbridge.JavaScriptExecutor.Factory.class,                    com.facebook.react.cxxbridge.JSBundleLoader.class);            method.setAccessible(true);            method.invoke(mReactInstanceManager,                    new com.facebook.react.cxxbridge.JSCJavaScriptExecutor.Factory(jscConfig.getConfigMap()),                    com.facebook.react.cxxbridge.JSBundleLoader.createFileLoader(getApplicationContext(), JS_BUNDLE_LOCAL_PATH));        } catch (NoSuchMethodException e) {            e.printStackTrace();        } catch (IllegalAccessException e) {            e.printStackTrace();        } catch (InvocationTargetException e) {            e.printStackTrace();        } catch (IllegalArgumentException e) {            e.printStackTrace();        } catch (NoSuchFieldException e){            e.printStackTrace();        }}

通过监听下载成功事件, 然后调用onJSBundleLoadedFromServer接口就可以看到立即更新的效果.

private CompleteReceiver mDownloadCompleteReceiver;private long mDownloadId;private void initDownloadManager() {   mDownloadCompleteReceiver = new CompleteReceiver();   registerReceiver(mDownloadCompleteReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));}private class CompleteReceiver extends BroadcastReceiver {    @Override    public void onReceive(Context context, Intent intent) {        long completeDownloadId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);        if (completeDownloadId == mDownloadId) {            onJSBundleLoadedFromServer();        }    }}

尝试以后果然可以更新, 当时心情非常好~ 可是......, 后面继续实现项目时发现, 动态更新后, 本地图片始终不显示, 远程图片可以.

接下来查看React Native, jsbundle 源码和查看资料, 终于寻的一点蛛丝马迹, 大概的意思如下:

如果bundle在sd卡【比如bundle在file://sdcard/react_native_update/index.android.bundle 那么图片目录在file://sdcard/react_native_update/drawable-mdpi】
如果你的bundle在assets里，图片资源要放到res文件夹里,例如res/drawable-mdpi

接下来按照该说法进行了实验, 发现确实可以. 当界面刷新时,心情格外好! 下面是详细代码实现(部分代码参考React-Native-Remote-Update项目,在这里直接引用):

package com.react.smart;import android.app.Activity;import android.app.DownloadManager;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.net.Uri;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.KeyEvent;import android.widget.Toast;import com.facebook.react.JSCConfig;import com.facebook.react.LifecycleState;import com.facebook.react.ReactInstanceManager;import com.facebook.react.ReactRootView;import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;import com.facebook.react.shell.MainReactPackage;import com.react.smart.componet.Package;import com.react.smart.utils.FileAssetUtils;import java.io.File;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;/** * Created by sky on 16/7/15. * https://github.com/hubcarl *//** * Created by sky on 16/9/4. * */public class UpdateReactActivity extends Activity implements DefaultHardwareBackBtnHandler {    private static final String TAG = "UpdateReactActivity";    public static final String JS_BUNDLE_REMOTE_URL = "https://raw.githubusercontent.com/hubcarl/smart-react-native-app/debug/app/src/main/assets/index.android.bundle";    public static final String JS_BUNDLE_LOCAL_FILE = "debug.android.bundle";    public static final String JS_BUNDLE_REACT_UPDATE_PATH = Environment.getExternalStorageDirectory().toString() + File.separator + "react_native_update";    public static final String JS_BUNDLE_LOCAL_PATH = JS_BUNDLE_REACT_UPDATE_PATH + File.separator + JS_BUNDLE_LOCAL_FILE;    private ReactInstanceManager mReactInstanceManager;    private ReactRootView mReactRootView;    private CompleteReceiver mDownloadCompleteReceiver;    private long mDownloadId;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        iniReactRootView(true);        initDownloadManager();        updateJSBundle(true);    }    // 如果bundle在sd卡【 比如bundle在file://sdcard/react_native_update/index.android.bundle 那么图片目录在file://sdcard/react_native_update/drawable-mdpi】    // 如果你的bundle在assets里，图片资源要放到res文件夹里,例如res/drawable-mdpi    private void iniReactRootView(boolean isRelease) {        ReactInstanceManager.Builder builder = ReactInstanceManager.builder()                .setApplication(getApplication())                .setJSMainModuleName(JS_BUNDLE_LOCAL_FILE)                .addPackage(new MainReactPackage())                .addPackage(new Package())                .setInitialLifecycleState(LifecycleState.RESUMED);        File file = new File(JS_BUNDLE_LOCAL_PATH);        if (isRelease && file != null && file.exists()) {            builder.setJSBundleFile(JS_BUNDLE_LOCAL_PATH);            Log.i(TAG, "load bundle from local cache");        } else {            builder.setBundleAssetName(JS_BUNDLE_LOCAL_FILE);            Log.i(TAG, "load bundle from asset");        }        mReactRootView = new ReactRootView(this);        mReactInstanceManager = builder.build();        mReactRootView.startReactApplication(mReactInstanceManager, "SmartReactApp", null);        setContentView(mReactRootView);    }    private void updateJSBundle(boolean isRelease) {        File file = new File(JS_BUNDLE_LOCAL_PATH);        if (isRelease && file != null && file.exists()) {            Log.i(TAG, "new bundle exists !");            return;        }        File rootDir = new File(JS_BUNDLE_REACT_UPDATE_PATH);        if (rootDir != null && !rootDir.exists()) {            rootDir.mkdir();        }        File res = new File(JS_BUNDLE_REACT_UPDATE_PATH + File.separator + "drawable-mdpi");        if (res != null && !res.exists()) {            res.mkdir();        }        FileAssetUtils.copyAssets(this, "drawable-mdpi", JS_BUNDLE_REACT_UPDATE_PATH);        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(JS_BUNDLE_REMOTE_URL));        request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);        request.setDestinationUri(Uri.parse("file://" + JS_BUNDLE_LOCAL_PATH));        DownloadManager dm = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);        mDownloadId = dm.enqueue(request);        Log.i(TAG, "start download remote js bundle file");    }    private void initDownloadManager() {        mDownloadCompleteReceiver = new CompleteReceiver();        registerReceiver(mDownloadCompleteReceiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));    }    private class CompleteReceiver extends BroadcastReceiver {        @Override        public void onReceive(Context context, Intent intent) {            long completeDownloadId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);            if (completeDownloadId == mDownloadId) {                onJSBundleLoadedFromServer();            }        }    }    private void onJSBundleLoadedFromServer() {        File file = new File(JS_BUNDLE_LOCAL_PATH);        if (file == null || !file.exists()) {            Log.i(TAG, "js bundle file download error, check URL or network state");            return;        }        Log.i(TAG, "js bundle file file success, reload js bundle");        Toast.makeText(UpdateReactActivity.this, "download bundle complete", Toast.LENGTH_SHORT).show();        try {            Class<?> RIManagerClazz = mReactInstanceManager.getClass();            Field f = RIManagerClazz.getDeclaredField("mJSCConfig");            f.setAccessible(true);            JSCConfig jscConfig = (JSCConfig)f.get(mReactInstanceManager);            Method method = RIManagerClazz.getDeclaredMethod("recreateReactContextInBackground",                    com.facebook.react.cxxbridge.JavaScriptExecutor.Factory.class,                    com.facebook.react.cxxbridge.JSBundleLoader.class);            method.setAccessible(true);            method.invoke(mReactInstanceManager,                    new com.facebook.react.cxxbridge.JSCJavaScriptExecutor.Factory(jscConfig.getConfigMap()),                    com.facebook.react.cxxbridge.JSBundleLoader.createFileLoader(getApplicationContext(), JS_BUNDLE_LOCAL_PATH));        } catch (NoSuchMethodException e) {            e.printStackTrace();        } catch (IllegalAccessException e) {            e.printStackTrace();        } catch (InvocationTargetException e) {            e.printStackTrace();        } catch (IllegalArgumentException e) {            e.printStackTrace();        } catch (NoSuchFieldException e){            e.printStackTrace();        }    }    @Override    protected void onDestroy() {        super.onDestroy();        unregisterReceiver(mDownloadCompleteReceiver);    }    @Override    public boolean onKeyUp(int keyCode, KeyEvent event) {        if (keyCode == KeyEvent.KEYCODE_MENU && mReactInstanceManager != null) {            mReactInstanceManager.showDevOptionsDialog();            return true;        }        return super.onKeyUp(keyCode, event);    }    @Override    public void onBackPressed() {        if (mReactInstanceManager != null) {            mReactInstanceManager.onBackPressed();        } else {            super.onBackPressed();        }    }    @Override    public void invokeDefaultOnBackPressed() {        super.onBackPressed();    }    @Override    protected void onPause() {        super.onPause();    }    @Override    protected void onResume() {        super.onResume();    }}

asset资源文件拷贝到sdcard, 当然实际实现时, 资源文件和jsbundle文件可以都应该放到远程服务器.

package com.react.smart.utils;import android.content.Context;import android.content.res.AssetManager;import android.util.Log;import java.io.*;/** * Created by sky on 16/9/19. */public class FileAssetUtils {    public static void copyAssets(Context context, String src, String dist) {        AssetManager assetManager = context.getAssets();        String[] files = null;        try {            files = assetManager.list(src);        } catch (IOException e) {            Log.e("tag", "Failed to get asset file list.", e);        }        for(String filename : files) {            InputStream in = null;            OutputStream out = null;            try {                in = assetManager.open(src + File.separator + filename);                File outFile = new File(dist + File.separator + src, filename);                out = new FileOutputStream(outFile);                copyFile(in, out);                in.close();                in = null;                out.flush();                out.close();                out = null;            } catch(IOException e) {                Log.e("tag", "Failed to copy asset file: " + filename, e);            }        }    }    public static void copyFile(InputStream in, OutputStream out) throws IOException {        byte[] buffer = new byte[1024];        int read;        while((read = in.read(buffer)) != -1){            out.write(buffer, 0, read);        }    }}

最后附上github项目地址: https://github.com/hubcarl/smart-react-native-app ,欢迎follow!

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