1.在App Store下载InjectionIII, 打开。
2.选择项目的根目录
3.项目的Appdelegate加入：
    [[NSBundle bundleWithPath:@"/Applications/InjectionIII.app/Contents/Resources/iOSInjection.bundle"] load];
运行报
Error loading /Applications/InjectionIII.app/Contents/Resources/iOSInjection.bundle/iOSInjection: dlopen(/Applications/InjectionIII.app/Contents/Resources/iOSInjection.bundle/iOSInjection, 265): Symbol not found: _$s19ArrayLiteralElements013ExpressibleByaB0PTl
  Referenced from: /Applications/InjectionIII.app/Contents/Resources/iOSInjection.bundle/iOSInjection
  Expected in: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator/libswiftCore.dylib
 in /Applications/InjectionIII.app/Contents/Resources/iOSInjection.bundle/iOSInjection

command+s就没有人报错误吗？
Loading .dylib ...
objc[4708]: Class ViewController is implemented in both /Users/hyman/Library/Developer/CoreSimulator/Devices/7C19EFEC-F0B4-4405-979A-358FA75F4A4F/data/Containers/Bundle/Application/A1A3313C-9092-4BBA-B2EF-604ECAD508D3/MTInjectionOC.app/MTInjectionOC (0x10f488d10) and /Users/hyman/Library/Containers/com.johnholdsworth.InjectionIII/Data/eval104.dylib (0x12d168138). One of the two will be used. Which one is undefined.
💉 Loaded .dylib - Ignore any duplicate class warning ^

刚开始没重写 - (void)injected { } , 发现修改一直没反应, 控制台还收到了相应警告
💉 Injection connected, watching /Users/user/JerseyCafe/JerseyCafe/MySampleCode/JSDPlayground/**
💉 *** Compiling /Users/user/JerseyCafe/JerseyCafe/MySampleCode/JSDPlayground/JSDPlayground/Class/Launch/JSDHomeVC.m ***
💉 Loading .dylib ...
objc[22080]: Class JSDHomeVC is implemented in both /Users/user/Library/Developer/CoreSimulator/Devices/042DBB6D-8059-43E7-A609-3034F6D949AD/data/Containers/Bundle/Application/4BCF4C6E-3650-484C-BAE8-7ACB3B3A3E6E/JSDPlayground.app/JSDPlayground (0x10695a278) and /Users/user/Library/Containers/com.johnholdsworth.InjectionIII/Data/eval101.dylib (0x12cf821d8). One of the two will be used. Which one is undefined.
💉 Loaded .dylib - Ignore any duplicate class warning ^
然后找了下 github Issue [Issue](https://github.com/johnno1962/InjectionIII/issues/101) 原来要在相应的文件下重写 injected 方法, 在 .m 下添加下列代码即可
Swift:
extension UIViewController {
  @objc func injected() {
    viewDidLoad()
    viewWillAppear(true)
    viewDidAppear(true)
  }
}
OC:
- (void)injected {
    
    [self viewDidLoad];
    [self viewWillAppear:YES];
    [self viewWillDisappear:YES];
}
直接修改代码即可, command + s 自动刷新。
不过还是收到相应警告。

@drunkenMouse，用你的方法在xcode 10.2上会出现👇错误提示，求教！！！

Error loading /Applications/InjectionIII.app/Contents/Resources/iOSInjection10.bundle/iOSInjection10: dlopen(/Applications/InjectionIII.app/Contents/Resources/iOSInjection10.bundle/iOSInjection10, 265): Symbol not found: _$SBOWV
  Referenced from: /Applications/InjectionIII.app/Contents/Resources/iOSInjection10.bundle/iOSInjection10
  Expected in: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator/libswiftCore.dylib
 in /Applications/InjectionIII.app/Contents/Resources/iOSInjection10.bundle/iOSInjection10

蛮好用的，但是有几个需要注意的地方：
1. 进行swizzling的类不要动态修改，否则二次交换，会引起死循环。
2. 不支持方法的删除：删除后，方法调用仍然有效，不抛异常。
3. 不支持新增类：新增类引入后使用无效。但类的重命名是有效的。
4. 属性新增、删除、修改：反射上体现不出来。
其中后三个的原因，不知道戴铭老师有没有什么见解。
在我的角度来看，应该不是InjectionIII的问题，可能与苹果动态库调用有关。

我这保存后悔报错
💉 *** Compiling /Users/zhaowangwang/Documents/中电科36所svn/E-Mobile/MeCenterViewController.m ***
💉 *** Re-compilation failed (/Users/zhaowangwang/Library/Containers/com.johnholdsworth.InjectionIII/Data/command.sh)
fatal error: malformed or corrupted AST file: 'could not find file '/Users/zhaowangwang/Documents/中电科36所svn/E-Mobile/RongIMLib.framework/Headers/RCAmrDataConverter.h' referenced by AST file '/Users/zhaowangwang/Library/Developer/Xcode/DerivedData/E-Mobile-brkkzascastenicojgygpmgoepqm/Build/Intermediates.noindex/PrecompiledHeaders/SharedPrecompiledHeaders/9438762758094351804/E-Mobile-Prefix.pch.gch''
1 error generated.
 ***
怎么破?

- (void)injected
+ (void)injected
INJECTION_BUNDLE_NOTIFICATION
我这边所有的修改只有写在这3个方法里才会刷新，并不能像图片上那样随修随变，并一直报dylib 重复警告

inject(tmpfile: String) 方法的代码大都是新类替换旧类，但是当我在- (void)injected里写入[self viewDidLoad];后，会发现并没有替换，而是重新创建了一遍新的UI,有请踩过坑的老哥发言😂

@Hyman 出现的问题怎么解决的？
💉 Loading .dylib ...
objc[10390]: Class ViewController is implemented in both /Users/lutaohua/Library/Developer/CoreSimulator/Devices/37453FFB-A4BA-4761-B590-BFAEB3C54A5D/data/Containers/Bundle/Application/342F3B0F-D638-4A99-89C6-3C8A04A25135/Mach_O_test.app/Mach_O_test (0x100b65ea8) and /Users/lutaohua/Library/Containers/com.johnholdsworth.InjectionIII/Data/eval101.dylib (0x11e8e3218). One of the two will be used. Which one is undefined.
💉 Loaded .dylib - Ignore any duplicate class warning ^