前言

• 本文以Xcode10为开发背景

一、找到系统自带代码块源文件

• Xcode5.1之前： /Applications/Xcode.app/Contents/PlugIns/IDECodeSnippetLibrary.ideplugin/Contents/Resources/SystemCodeSnippets.codesnippets
• Xcode 5.1 - Xcode9：
  /Applications/Xcode.app/Contents/Frameworks/IDEKit.framework/Versions/A/Resources/SystemCodeSnippets.codesnippets
• Xcode10：
  /Applications/Xcode.app/Contents/PlugIns/IDESourceEditor.framework/Versions/A/Resources/SystemCodeSnippets.codesnippets
• 打开它之后代码如下

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<array>
    <dict>
        <key>IDECodeSnippetVersion</key>
        <integer>1</integer>
        <key>IDECodeSnippetCompletionPrefix</key>
        <string>@protocol</string>
        <key>IDECodeSnippetContents</key>
        <string>@protocol &lt;#protocol name#&gt; &lt;NSObject&gt;

&lt;#methods#&gt;

@end</string>
        <key>IDECodeSnippetIdentifier</key>
        <string>986936BB-E0FE-4E7E-9A79-E3C77528204E</string>
        <key>IDECodeSnippetLanguage</key>
        <string>Xcode.SourceCodeLanguage.Objective-C</string>
        <key>IDECodeSnippetSummary</key>
        <string>Define an Objective-C protocol.</string>
        <key>IDECodeSnippetTitle</key>
        <string>Objective-C Protocol Definition</string>
        <key>IDECodeSnippetCompletionScopes</key>
        <array>
            <string>TopLevel</string>
        </array>
    </dict>
    <dict>
        <key>IDECodeSnippetVersion</key>
        <integer>1</integer>
        <key>IDECodeSnippetCompletionPrefix</key>
        <string>initialize</string>
        <key>IDECodeSnippetContents</key>
        <string>+ (void)initialize
{
    if (self == [&lt;#ClassName#&gt; class]) {
        &lt;#statements#&gt;
    }
}</string>
        <key>IDECodeSnippetIdentifier</key>
        <string>F9022097-FD7D-45DC-A790-A2EA6845386F</string>
        <key>IDECodeSnippetLanguage</key>
        <string>Xcode.SourceCodeLanguage.Objective-C</string>
        <key>IDECodeSnippetSummary</key>
        <string>Initialize a class before it receives its first message.</string>
        <key>IDECodeSnippetTitle</key>
        <string>Objective-C +initialize Method</string>
        <key>IDECodeSnippetCompletionScopes</key>
        <array>
            <string>ClassImplementation</string>
        </array>
    </dict>
由于篇幅原因，不全显示在这里

二、找到开发者自定义代码块的地址

• 地址：
  ~/Library/Developer/Xcode/UserData/CodeSnippets/

• 注意：只有自己定义过代码块，才会在UserData目录下存在CodeSnippets文件夹，否则是不存在的。

• 若未自定义过代码块，则可以使用如下方法

• Xcode10之前：
  选中随意一段代码，按住拖到右下角的{}中，快速填空，即可

• Xcode10：

  
  图1：选中->右键
  

  另外，查看代码块的位置变成了右上角

  
  图2：代码块位置

• 此时再打开~/Library/Developer/Xcode/UserData/CodeSnippets/
  

  图3：.codesnippet文件

三、修改系统样式

• 1.找到想要修改的样式，比如if代码块
  

  图4：找到想改的代码块

• 2.打开自定义的某.codesnippet文件

  
  图5：修改copy过来的代码

四、改改文件名啥的-。-，这个就不写了吧

右键修改文件名了解一下