参考：https://github.com/flutter/flutter/wiki/Add-Flutter-to-existing-apps

本文代码：https://github.com/yonglinwang002/TestFlutter

一、生成Flutter 模块

假设已有工程 TestFlutter

$ cd TestFlutter/

$ flutter create -t module flutter_library

执行后会生成

flutter_library 目录

结构如下

Flutter模块

二、使用宿主工程依赖Flutter模块

在主工程中增加一个 Group 如名为Flutter

生成后结构

TestFlutter/

    Flutter/

      Flutter.xcconfig

    TestFlutter/

      AppDelegate.h

      AppDelegate.m

      :

      Debug.xcconfig

      Release.xcconfig

编辑Flutter.xcconfig 文件

#include "../flutter_library/.ios/Flutter/Generated.xcconfig"

ENABLE_BITCODE=NO

Debug.xcconfig文件

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

Release.xcconfig文件

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

FLUTTER_BUILD_MODE=release

使用xcconfig相应配置

三、设置执行Flutter的脚本

在Run Script中增加

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

Run Script

四、执行脚本并把Framework加入工程

Cmd+B，Build工程，编译后，Flutter目录中生成如下

编译后生成目录

把其中的flutter_assets 目录以及Flutter.framework加入到工程的Flutter Group中

注意添加flutter_assets目录时，选择 Create forlder references !!!! (我就是这里没注意，后面始终出错)

添加Flutter相关文件

五、添加调用Flutter语句

这里就没有什么好说的了，

#import "Flutter/Flutter.h"

- (void)viewDidLoad {
    [super viewDidLoad];
    [self.view setBackgroundColor:[UIColor orangeColor]];
   
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    [button addTarget:self
               action:@selector(handleButtonAction)
     forControlEvents:UIControlEventTouchUpInside];
    [button setTitle:@"Press me" forState:UIControlStateNormal];
    [button setBackgroundColor:[UIColor blueColor]];
    button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
    [self.view addSubview:button];
   
    // Do any additional setup after loading the view, typically from a nib.
}


- (void)handleButtonAction {
    FlutterViewController* flutterViewController = [[FlutterViewController alloc] init];
    flutterViewController.view.frame = [UIScreen mainScreen].bounds;
//    [flutterViewController setInitialRoute:@"route1"];//如果设置了router，可以到不同的页面
    [self presentViewController:flutterViewController animated:NO completion:nil];
}

Cmd+R吧，就出来了

这里说一个热重载的方法 （Hot Reload） 在终端上

$ cd flutter_library

$ flutter attach

Waiting for a connection from Flutter on iPhone X...

然后，在XCode中 Cmd+R 执行，待进入到FlutterView页面时，

终端变成如下

这时如果修改了dart文件 ，再按r就可以重新载入

q 退出