参考原文Swift【优化Swift项目编译时间】
借助第三方插件
BuildTimeAnalyzer-for-Xcode
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使用方法
1.下载项目后,运行会弹出一个窗口
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2.按照上面提示,打开自己需要编译的项目,在build setting中，设置Other Swift Flags为-Xfrontend -debug-time-function-bodies
然后clean ,编译,然后就看到最上面第一个示例图
通过参考其他博客,并且亲测各种方法
减少编译时长的方法
1.使用自定义或者第三方组件,建议用framework的方式集成到项目中,会减少编译时长
在网上找了个第三方的下拉刷新,这个第三方没有支持carthage然后自己制作了一个framework进行测试
直接用原代码无framework
先clean 清理DerivedData缓存
1. 21s 2.14s 3. 13s 4. 13s 5. 13s 6. 13s 7. 12s
排除 第一个偏差大的
78/6 = 13
如果仅仅是clean然后编译 6s 6s 5s 5s 5s 5s 总32 平均 =5.33333
用framework
先clean 清理DerivedData缓存
1. 16s 2. 12s 3. 12s 4.12s 5.10s 46/4 = 11.5
仅仅是clean 5s 3s 4s 6s 4s 4s 总26 平均 = 4.33333
2.明确指明类型，不要让编译器去自动推导
这个结论其实不准确,亲测如下
// 类型声明之后: 48.89ms 47.78ms clean之后: 50.38ms 49.00ms
// 自动推导 45.62 47.56ms 49.19ms clean之后: 50.21ms 49.23ms
// : Dictionary<String, Any>
let myCompany = [
"employees": [
"employee 1": ["attribute": "value"],
"employee 2": ["attribute": "value"],
"employee 3": ["attribute": "value"],
"employee 4": ["attribute": "value"],
"employee 5": ["attribute": "value"],
"employee 6": ["attribute": "value"],
"employee 7": ["attribute": "value"],
"employee 8": ["attribute": "value"],
"employee 9": ["attribute": "value"],
"employee 10": ["attribute": "value"],
"employee 11": ["attribute": "value"],
"employee 12": ["attribute": "value"],
"employee 13": ["attribute": "value"],
"employee 14": ["attribute": "value"],
"employee 15": ["attribute": "value"],
"employee 16": ["attribute": "value"],
"employee 17": ["attribute": "value"],
"employee 18": ["attribute": "value"],
"employee 19": ["attribute": "value"],
"employee 20": ["attribute": "value"],
]
]
3.尽可能将nil判断写成if let方式解包
var num : CGFloat?
num = 44
if num != nil{
print(num)
}
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var num : CGFloat?
num = 44
if let newNum = num {
print(newNum)
}
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4.尽量用array.append(data),而不是用array+[data]
// Build time: 246.50ms 243.55ms
let systemOptions = [ 7, 14, 30, -1 ]
let systemNames = (0...2).map{ String(format: "%d", systemOptions[$0]) } + [NSLocalizedString("everything", comment: "")]
let count = systemOptions.count
let labelNames = Array(systemNames[0..<count]) + [systemNames.last!]
// Build time: 184.18ms
let systemOptions = [ 7, 14, 30, -1 ]
var systemNames = systemOptions.dropLast().map{ String(format: "%d", $0) }
systemNames.append(NSLocalizedString("everything", comment: ""))
let count = systemOptions.count
var labelNames = Array(systemNames[0..<count])
labelNames.append(systemNames.last!)
5. 尽量不要用三目运算,用if else代替三目运算
// Build time: 76.09ms 74.51ms
let type = 44
let labelNames = type == 0 ? (1...5).map{ type0ToString($0) } : (0...2).map{type0ToString($0)}
// Build time: 71.96ms 72.48ms
var labelNames: [String]
if type == 0 {
labelNames = (1...5).map{type0ToString($0)}
} else {
labelNames = (0...2).map{type0ToString($0)}
}
6.尽量不要用一些内置函数例如round/ceil/floor等等
let a: CGFloat = 22
let b: CGFloat = 22
let c: CGFloat = 22
let d: CGFloat = 22
let e: CGFloat = 22
// Build time: 19.51ms 18.66ms
// let expansion = a - b - c + round(d * 0.66) + e
// Build time: 15.07ms 13.68ms
let expansion = a - b - c + d * 0.66 + e
6.尽量使用纯Swift类型,不要和Objective-C混编
尽可能避免混合地使用Swift类型和NSObject子类，会对性能的提高有所帮助
7.尽量避免无意义的log，保持好的编码习惯
参考文章:Swift性能探索和优化分析
