前言

Flutter 是一个颇有潜力的框架，可是目前使用Flutter的APP并不算不少，相关资料并不丰富，介绍现有工程引入Flutter的相关文章也比较少。项目从零开始，引入Flutter操做比较简单，可是现有工程引入Flutter 须要费不少精力和时间，这里是我在完成现有iOS工程引入Flutter后写的一次总结文章。ios

Flutter 环境搭建

首先是要搭建Flutter环境，以前也写了一篇相关文章搭建Flutter-iOS开发环境，能够参考一下能够去官网查看：github.com/flutter/flu… 比较简单，这里不作赘述。git

现有iOS工程引入Flutter

1、创建Flutter module

首先创建flutter module，主要是用于获取改flutter app中的Generated.xcconfig和frameworkgithub

cd some/path/
$ flutter create -t module my_flutter
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也能够用xcode

flutter create app
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创建flutter app，flutter app中也有Generated.xcconfig和frameworkbash

2、新建配置文件

根据官网，须要在工程中创建三个配置文件： Flutter.xcconfig 、Debug.xcconfig、Release.xcconfig 在XCode工程对应目录，右击，选择新建文件（New File），选中建立xcconfig文件，如图： markdown

在`Flutter.xcconfig`中填写：

//这里填写前面创建的flutter module 的Generated.xcconfig的路径
#include "../../my_flutter/.ios/Flutter/Generated.xcconfig"
ENABLE_BITCODE=NO
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在 `Debug.xcconfig`中填写:

#include "../Flutter/Flutter.xcconfig"

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在 Release.xcconfig中填写:app

#include "../Flutter/Flutter.xcconfig"
FLUTTER_BUILD_MODE=release
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若是工程中用cocoapods管理，须要在 Debug.xcconfig和Release.xcconfig添加pod的路径：框架

例如 Release.xcconfig中ide

#include "Flutter.xcconfig"
#include "工程路径/Pods/Target Support Files/******.release.xcconfig"//pod路径
FLUTTER_BUILD_MODE=release
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在准备好这些xcconfig文件后，须要到XCode工程PROJECT（注意是PROJECT,不是Target）中的Configuration选项里，将对应的target选择成前面的xcconfig文件，Debug用Debug.xcconfig, Release用 Release.xcconfigoop

注意：进行Archive打包的时候，不管是Debug包仍是Release包，须要切换到Release.xcconfig，否则会报错。

3、为编译Dart引入相关build phase

在工程的Build Phase中新建一个Run Script,用于编译时运行脚本，创建方法如图：

创建Run Script后，须要移动其对应的位置，须要在Target dependencies以后，若是用cocoapods管理工程须要在，Check Pods Manifest.lock以后：

在脚本框中，填入如下代码，用于引进Flutter中的xcode_backend脚本：

"$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh" build
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如图：

4、生成和添加Framework

完成前面的配置后，即可以在XCode对工程进行编译build (Command+B)，在提示“ Build Success ” 后，在iOS工程文件夹中会生成一个Flutter文件夹，将其加入工程目录中,建议和刚才xcconfig所在目录并列，

右键项目目录，选择 Add Files to 'xxx' ，Options选Create groups，添加编译生成的Flutter文件夹。须要注意可是：Flutter目录下有个flutter_assets文件，不能使用Create groups的方式添加，只能用Creat folder references的Options，不然Flutter页面会空白渲染不出来。能够删了flutter_assets在用Creat folder references从新添加。

在添加完Flutter 文件夹以后，去Embeded Binaries中添加App.framework和Flutter.framework

5、AppDelegate改造

Flutter须要和APP进行交互，须要对AppDelegate 进行改造：

AppDelegate.h文件中：

#import <Flutter/Flutter.h>

@interface AppDelegate : FlutterAppDelegate <UIApplicationDelegate, FlutterAppLifeCycleProvider>

@end
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AppDelegate.m 文件中：

#import "AppDelegate.h"

@interface AppDelegate ()
    
@end

@implementation AppDelegate
{
  FlutterPluginAppLifeCycleDelegate *_lifeCycleDelegate;
}
    
- (instancetype)init {
    if (self = [super init]) {
        _lifeCycleDelegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
    }
    return self;
}
    
- (BOOL)application:(UIApplication*)application
didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
    return [_lifeCycleDelegate application:application didFinishLaunchingWithOptions:launchOptions];
}
    
- (void)applicationDidEnterBackground:(UIApplication*)application {
    [_lifeCycleDelegate applicationDidEnterBackground:application];
}
    
- (void)applicationWillEnterForeground:(UIApplication*)application {
    [_lifeCycleDelegate applicationWillEnterForeground:application];
}
    
- (void)applicationWillResignActive:(UIApplication*)application {
    [_lifeCycleDelegate applicationWillResignActive:application];
}
    
- (void)applicationDidBecomeActive:(UIApplication*)application {
    [_lifeCycleDelegate applicationDidBecomeActive:application];
}
    
- (void)applicationWillTerminate:(UIApplication*)application {
    [_lifeCycleDelegate applicationWillTerminate:application];
}
    
- (void)application:(UIApplication*)application
didRegisterUserNotificationSettings:(UIUserNotificationSettings*)notificationSettings {
    [_lifeCycleDelegate application:application
didRegisterUserNotificationSettings:notificationSettings];
}
    
- (void)application:(UIApplication*)application
didRegisterForRemoteNotificationsWithDeviceToken:(NSData*)deviceToken {
    [_lifeCycleDelegate application:application
didRegisterForRemoteNotificationsWithDeviceToken:deviceToken];
}
    
- (void)application:(UIApplication*)application
didReceiveRemoteNotification:(NSDictionary*)userInfo
fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler {
    [_lifeCycleDelegate application:application
       didReceiveRemoteNotification:userInfo
             fetchCompletionHandler:completionHandler];
}
    
- (BOOL)application:(UIApplication*)application
            openURL:(NSURL*)url
            options:(NSDictionary<UIApplicationOpenURLOptionsKey, id>*)options {
    return [_lifeCycleDelegate application:application openURL:url options:options];
}
    
- (BOOL)application:(UIApplication*)application handleOpenURL:(NSURL*)url {
    return [_lifeCycleDelegate application:application handleOpenURL:url];
}
    
- (BOOL)application:(UIApplication*)application
            openURL:(NSURL*)url
  sourceApplication:(NSString*)sourceApplication
         annotation:(id)annotation {
    return [_lifeCycleDelegate application:application
                                   openURL:url
                         sourceApplication:sourceApplication
                                annotation:annotation];
}
    
- (void)application:(UIApplication*)application
performActionForShortcutItem:(UIApplicationShortcutItem*)shortcutItem
  completionHandler:(void (^)(BOOL succeeded))completionHandler NS_AVAILABLE_IOS(9_0) {
    [_lifeCycleDelegate application:application
       performActionForShortcutItem:shortcutItem
                  completionHandler:completionHandler];
}
    
- (void)application:(UIApplication*)application
handleEventsForBackgroundURLSession:(nonnull NSString*)identifier
  completionHandler:(nonnull void (^)(void))completionHandler {
    [_lifeCycleDelegate application:application
handleEventsForBackgroundURLSession:identifier
                  completionHandler:completionHandler];
}
    
- (void)application:(UIApplication*)application
performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler {
    [_lifeCycleDelegate application:application performFetchWithCompletionHandler:completionHandler];
}
    
- (void)addApplicationLifeCycleDelegate:(NSObject<FlutterPlugin>*)delegate {
    [_lifeCycleDelegate addDelegate:delegate];
}

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6、新建FlutterViewController

主要配置基本上已经完成，只要在main.dart实现Flutter的业务代码便可

在原有工程中，创建FlutterViewController来承载 main.dart实现的Flutter页面，如：

self.flutterViewController = [[FlutterViewController alloc] initWithProject:nil nibName:nil bundle:nil];
    [self.navigationController pushViewController:self.flutterViewController animated:YES];
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后语

到这里现有iOS工程引入Flutter的工做就完成了，一些细节上的修改须要根据场景进行修改，例如Flutter和Native的数据通讯等。

Flutter-现有iOS工程引入Flutter

前言