react-native作為跨平臺的語言好處主要體現(xiàn)在跨平臺和能進(jìn)行熱更新脯倚。要實(shí)現(xiàn)熱更新通常想到使用某個第三方組件實(shí)現(xiàn)，常用的就是微軟的codepush和RN中文網(wǎng)的react-native-pushly.如果不想使用第三方我們也可以自己實(shí)現(xiàn)获洲。所謂的熱更新就是下載新的bundle壓縮包然后解壓，讓app加載這個補(bǔ)丁包那槽。根據(jù)我的實(shí)踐，一個壓縮的bundle包也只有兩三M周偎，所有只要在原生端下載這個壓縮包然后解壓就行了翁逞。
大概思路：
1.沙盒里建三個文件夾和一個plist文件总珠，一個放補(bǔ)丁包（IOSBundle）屏鳍，一個放下載的壓縮包（BundleZip解壓后會刪除該壓縮包），一個放記錄版本號與補(bǔ)丁號的plist文件（PatchPlist）局服， 判斷存放補(bǔ)丁包的文件夾下是否有下載的補(bǔ)丁钓瞭，同時判斷記錄的版本號與當(dāng)前版本號是否相同，不相同有補(bǔ)丁也不加載淫奔。

2.網(wǎng)絡(luò)請求獲取是否有補(bǔ)丁需要下載山涡，如果有則拿到下載的url進(jìn)行下載，如果沒有則不下載唆迁。網(wǎng)絡(luò)請求使用AFN,解壓用了ZipArchive

3.如果需要下載補(bǔ)丁則先下載壓縮包鸭丛，然后解壓，解壓完成時刪除壓縮包唐责，將獲得的版本號和補(bǔ)丁號寫入plist鳞溉。下次app重啟是就會加載補(bǔ)丁包，熱跟新完成鼠哥。

ps:如果想在上架app Store審核之后用熱更新更新新需求而不重新提交審核熟菲，那圖片就不能放在xcode里了，所有引用圖片的方式需要使用require的方式朴恳，因?yàn)榉旁趚code里的圖片是沒辦法熱更新的〕保現(xiàn)在說的這種更適合修復(fù)線上js寫的邏輯bug，無法修改原生代碼.

在AppDelegate中于颖，啟動的時候判斷沙盒文件夾是否有已經(jīng)下載的補(bǔ)丁包呆贿，如果有就加載。但是如果安裝了新版本且是覆蓋安裝森渐，這樣啟動時加載的會仍然是那個補(bǔ)丁包做入，所以為了防止這種情況冒晰，我們需要比較上次下載補(bǔ)丁時記錄的版本號和當(dāng)前版本號，如果不同母蛛，即使沙盒里有補(bǔ)丁包也不加載

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
   NSURL *jsCodeLocation;
   NSString* iOSBundlePath = [[[UpdateDataLoader sharedInstance] iOSFileBundlePath] stringByAppendingString:@"/bundle/index.ios.jsbundle"];
  if ([[NSFileManager defaultManager] fileExistsAtPath:iOSBundlePath] && [self compareAppVersionIsSame]) {
#ifdef DEBUG
    //開發(fā)包
    jsCodeLocation = [[RCTBundleURLProvider sharedSettings] jsBundleURLForBundleRoot:@"index.ios" fallbackResource:nil];
#else
    //加載熱修復(fù)下載的bundle
    jsCodeLocation = [NSURL URLWithString:iOSBundlePath];
#endif
  }else{
#ifdef DEBUG
     //開發(fā)包
     jsCodeLocation = [[RCTBundleURLProvider sharedSettings] jsBundleURLForBundleRoot:@"index.ios" fallbackResource:nil];
#else
     //離線包
     jsCodeLocation = [[NSBundle mainBundle] URLForResource:@"bundle/index.ios" withExtension:@"jsbundle"];
#endif
  }
  RCTRootView *rootView = [[RCTRootView alloc] initWithBundleURL:jsCodeLocation
                                                      moduleName:@"ReactFlyApp"
                                               initialProperties:nil
                                                   launchOptions:launchOptions];
//因?yàn)槲覍嚎s包托管在leanCould上翩剪，此處是設(shè)置該SDK,如果有自己的后臺則直接請求是否需要更新補(bǔ)丁
[self AVOSCloudSetting];
。彩郊。。
}

//判斷熱更新記錄的版本與當(dāng)前版本是否相同
-(BOOL)compareAppVersionIsSame{
  NSString *currentAppVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];
  NSDictionary *dic = [[UpdateDataLoader sharedInstance]getDataFromIosBundlePlist];
  NSString *recordAppVersion = @"";
  if(dic !=nil && dic[@"appVerion"]){
    recordAppVersion = dic[@"appVerion"] ;
  }
  return [currentAppVersion isEqualToString:recordAppVersion];
}

-(void)AVOSCloudSetting{
  [[UpdateDataLoader sharedInstance] createHotFixBundlePath]; //在沙盒新建三個文件夾和一個plist文件蚪缀，如果有則不新建
  [AVOSCloud setApplicationId:AVOSCloudID clientKey:AVOSCloudKey];
#ifdef DEBUG
  [AVOSCloud setAllLogsEnabled:YES];
#else
  [AVOSCloud setAllLogsEnabled:FALSE];
#endif
  [[UpdateDataLoader sharedInstance] downloadNewBundle];//進(jìn)行網(wǎng)絡(luò)請求判斷是否需要下載補(bǔ)丁
}

UpdateDataLoader文件主要是創(chuàng)建文件夾秫逝，plist文件和判斷是否需要下載

#import <Foundation/Foundation.h>

@interface UpdateDataLoader : NSObject

@property (nonatomic, strong) NSDictionary* versionInfo;
+ (UpdateDataLoader *) sharedInstance;

//創(chuàng)建bundle路徑
-(void)createHotFixBundlePath;

//檢查下載熱更新包
-(void)downloadNewBundle;

-(void)writeAppVersionInfoWithDictiony:(NSDictionary*)info;

-(NSString*)iOSFileBundlePath;

-(NSDictionary*)getDataFromIosBundlePlist;
@end

----------------------------------------------------------------------------------------= = ------------------------------

#import "UpdateDataLoader.h"
#import "DownLoadTool.h"
#import "Network.h"
#import "AFNetworking.h"
#import <AVOSCloud/AVOSCloud.h>
@implementation UpdateDataLoader

+ (UpdateDataLoader *) sharedInstance
{
  static UpdateDataLoader *sharedInstance = nil;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    sharedInstance = [[UpdateDataLoader alloc] init];
  });
  return sharedInstance;
}

//創(chuàng)建bundle路徑
-(void)createHotFixBundlePath{
  if([[NSFileManager defaultManager]fileExistsAtPath:[self getVersionPlistPath]]){
    return;
  }
  NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
  NSString *path = [paths lastObject];
  NSFileManager *fileManager = [NSFileManager defaultManager];
  NSString *directryPath = [path stringByAppendingPathComponent:@"IOSBundle"];
  [fileManager createDirectoryAtPath:directryPath withIntermediateDirectories:YES attributes:nil error:nil];
  NSString *bundleZipPath = [path stringByAppendingPathComponent:@"BundleZip"];
  [fileManager createDirectoryAtPath:bundleZipPath withIntermediateDirectories:YES attributes:nil error:nil];
  NSString *PatchPlistPath = [path stringByAppendingPathComponent:@"PatchPlist"];
  [fileManager createDirectoryAtPath:PatchPlistPath withIntermediateDirectories:YES attributes:nil error:nil];
  NSString *filePath = [PatchPlistPath stringByAppendingPathComponent:@"Version.plist"];
  [fileManager createFileAtPath:filePath contents:nil attributes:nil];
}

//獲取版本信息,有下載就下載新的熱更新包
-(void)downloadNewBundle{
  NSString *version = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];
  NSDictionary *dic = [self getDataFromIosBundlePlist];
  int patchCode = 0;
  if(dic !=nil && dic[@"patchCode"]){
    patchCode = [dic[@"patchCode"] intValue];
  }
//此處應(yīng)該將version和patchCode穿給后臺，且要求后臺返回數(shù)據(jù)要按修改時間升序（時間越新越靠前）询枚，拿version到數(shù)據(jù)庫中匹配违帆，與該version相同且大于該patchCode，有滿足條件的數(shù)據(jù)則表明有補(bǔ)丁包需要下載金蜀，這時返回一個數(shù)組刷后，我們?nèi)?shù)組的第一個對象，該對象包含需要下載的url,然后下載渊抄。應(yīng)該我使用了leanCloud尝胆，所以代碼是這樣
 AVQuery *fileQuery = [AVQuery queryWithClassName:@"hot_update_file"];
  [fileQuery whereKey:@"patchCode" greaterThan:@(patchCode)];
  [fileQuery whereKey:@"version" equalTo:version];
  [fileQuery orderByDescending:@"createdAt"];
  [fileQuery findObjectsInBackgroundWithBlock:^(NSArray *lists, NSError *error) {
    if(error==nil){
      if(lists!=nil && lists.count>0){
        AVObject *avObject = lists.firstObject;
        if(avObject !=nil){
          NSDictionary *dic = (NSDictionary *)[avObject objectForKey:@"localData"];
          NSString *patchCode = (NSString *)dic[@"patchCode"];
          if(dic[@"pathfile"]!=nil){
            AVFile *file = dic[@"pathfile"];
            NSString *downLoadURL = (NSString *)file.url;
            [[DownLoadTool defaultDownLoadTool] downLoadWithUrl:downLoadURL patchCode:patchCode serverAppVersion:version];
          }
        }
      }
    }
  }];
}

//獲取Bundle 路徑
-(NSString*)iOSFileBundlePath{
  NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString* path = [paths objectAtIndex:0];
  NSString* filePath = [path stringByAppendingPathComponent:@"/IOSBundle"];
  return  filePath;
}

//獲取版本信息儲存的文件路徑
-(NSString*)getVersionPlistPath{
  NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString* path = [paths objectAtIndex:0];
  NSString* filePath = [path stringByAppendingPathComponent:@"/PatchPlist/Version.plist"];
  return filePath;
}

//讀取plist文件數(shù)據(jù)
-(NSDictionary*)getDataFromIosBundlePlist{
  return [NSDictionary dictionaryWithContentsOfFile:[self getVersionPlistPath]];
}

//創(chuàng)建或修改版本信息
-(void)writeAppVersionInfoWithDictiony:(NSDictionary*)dictionary{
  NSString* filePath  = [self getVersionPlistPath];
  [dictionary writeToFile:filePath atomically:YES];
}
@end

下面就是拿到url后下載壓縮包，需要主要的是下載默認(rèn)是掛起的护桦，需要我們手動開啟[downloadTask resume];

#import <Foundation/Foundation.h>

@interface DownLoadTool : NSObject
@property (nonatomic, strong) NSString *zipPath;

+ (DownLoadTool *) defaultDownLoadTool;

//根據(jù)url下載相關(guān)文件
-(void)downLoadWithUrl:(NSString*)url patchCode:(NSString *)patchCode serverAppVersion:(NSString *)serverVersion;

@end

----------------------------------------------------------------------------------------= = ------------------------------


#import "DownLoadTool.h"
#import "ZipArchive.h"
#import "AFURLSessionManager.h"
#import "UpdateDataLoader.h"

@implementation DownLoadTool
+ (DownLoadTool *) defaultDownLoadTool{
  static DownLoadTool *sharedInstance = nil;
  static dispatch_once_t onceToken;
  
  dispatch_once(&onceToken, ^{
    sharedInstance = [[DownLoadTool alloc] init];
  });
  
  return sharedInstance;
}

-(void)downLoadWithUrl:(NSString*)url patchCode:(NSString *)patchCode serverAppVersion:(NSString *)serverVersion{
  //根據(jù)url下載相關(guān)文件
  NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
  AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];
  NSURL *URL = [NSURL URLWithString:url];
  NSURLRequest *request = [NSURLRequest requestWithURL:URL];
  NSURLSessionDownloadTask *downloadTask = [manager downloadTaskWithRequest:request progress:^(NSProgress * _Nonnull downloadProgress) {
    //獲取下載進(jìn)度
    NSLog(@"Progress is %f", downloadProgress.fractionCompleted);
  } destination:^NSURL *(NSURL *targetPath, NSURLResponse *response) {
    //有返回值的block含衔，返回文件存儲路徑
    NSURL *documentsDirectoryURL = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:NO error:nil];
    NSURL* targetPathUrl = [documentsDirectoryURL URLByAppendingPathComponent:@"BundleZip"];
    return [targetPathUrl URLByAppendingPathComponent:[response suggestedFilename]];
    
  } completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error) {
    if(error){
      //下載出現(xiàn)錯誤
      NSLog(@"%@",error);
    }else{
      //下載成功
      if([filePath absoluteString].length>7){
        self.zipPath = [[filePath absoluteString] substringFromIndex:7];
      }
      //下載成功后更新本地存儲信息
      NSDictionary*infoDic=@{@"patchCode":serverVersion,@"appVerion":serverVersion,};
      [[UpdateDataLoader sharedInstance] writeAppVersionInfoWithDictiony:infoDic];
      //解壓并刪除壓縮包
        [self unZip];
    }
  }];
  [downloadTask resume];
}

//解壓壓縮包
-(void)unZip{
  if (self.zipPath == nil) {
    return;
  }
  //檢查Document里有沒有bundle文件夾
  NSString* path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
  NSString* bundlePath = [path stringByAppendingPathComponent:@"/IOSBundle"];
   dispatch_queue_t _opQueue = dispatch_queue_create("cn.reactnative.hotupdate", DISPATCH_QUEUE_SERIAL);
  dispatch_async(_opQueue, ^{
    BOOL isDir;
    //如果有，則刪除后解壓二庵，如果沒有則直接解壓
    if ([[NSFileManager defaultManager] fileExistsAtPath:bundlePath isDirectory:&isDir]&&isDir) {
      [[NSFileManager defaultManager] removeItemAtPath:bundlePath error:nil];
    }
    NSString *zipPath = self.zipPath;
    NSString *destinationPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]stringByAppendingString:@"/IOSBundle"];
    [SSZipArchive unzipFileAtPath:zipPath toDestination:destinationPath progressHandler:^(NSString * _Nonnull entry, unz_file_info zipInfo, long entryNumber, long total) {
    } completionHandler:^(NSString * _Nonnull path, BOOL succeeded, NSError * _Nullable error) {
      //刪除壓縮包
      NSError* merror = nil;
      [[NSFileManager defaultManager] removeItemAtPath:self.zipPath error:&merror];
    }];
  });
}
@end

至此我們的熱更新就完成了贪染，我親測這種方法是可以完成熱更新的。demo
這篇文章參考了別人的文章催享，但是在實(shí)踐過程中發(fā)現(xiàn)有的寫得有問題杭隙，且有的地方考慮不是很全面，所以在此基礎(chǔ)上進(jìn)行了修改完善因妙，當(dāng)然我寫的這種也許也有問題痰憎，有發(fā)現(xiàn)的望提出，我也及時更正兰迫。
參考：
React-Native開發(fā)iOS篇-熱更新的實(shí)現(xiàn)
React-Native開發(fā)iOS篇-熱更新的實(shí)現(xiàn)