ios - SwiftyJSON 性能问题-6ren

ios - SwiftyJSON 性能问题

转载作者：IT王子更新时间：2023-10-29 05:19:02

在从我们的 API 使用 SwiftyJson 解析 JSON 并填充核心数据时，我遇到了严重的性能问题。

数据是使用 Alamofire 下载的，它运行良好，但使用 SwiftyJson 解析 JSON 非常慢。为了查看库是否真的是问题所在，我在解析数据的众多地方之一重写了 json 解析。在下面的代码中，我正在解析大约 400 个旅游景点之一的开放时间。

查看这些屏幕截图中的差异，7.7 秒到 185 毫秒:

enter image description here

Swifty 方式:

    let openDescription:String = json["OpeningHours"]["OpeningHoursGenericExceptions"].string!
    let monOpen:[String]    = json["OpeningHours"]["Monday"]["From"].string!.componentsSeparatedByString(":")
    let monClose:[String]   = json["OpeningHours"]["Monday"]["To"].string!.componentsSeparatedByString(":")
    let tueOpen:[String]    = json["OpeningHours"]["Tuesday"]["From"].string!.componentsSeparatedByString(":")
    let tueClose:[String]   = json["OpeningHours"]["Tuesday"]["To"].string!.componentsSeparatedByString(":")
    let wedOpen:[String]    = json["OpeningHours"]["Wednesday"]["From"].string!.componentsSeparatedByString(":")
    let wedClose:[String]   = json["OpeningHours"]["Wednesday"]["To"].string!.componentsSeparatedByString(":")
    let thuOpen:[String]    = json["OpeningHours"]["Thursday"]["From"].string!.componentsSeparatedByString(":")
    let thuClose:[String]   = json["OpeningHours"]["Thursday"]["To"].string!.componentsSeparatedByString(":")
    let friOpen:[String]    = json["OpeningHours"]["Friday"]["From"].string!.componentsSeparatedByString(":")
    let friClose:[String]   = json["OpeningHours"]["Friday"]["To"].string!.componentsSeparatedByString(":")
    let satOpen:[String]    = json["OpeningHours"]["Saturday"]["From"].string!.componentsSeparatedByString(":")
    let satClose:[String]   = json["OpeningHours"]["Saturday"]["To"].string!.componentsSeparatedByString(":")
    let sunOpen:[String]    = json["OpeningHours"]["Sunday"]["From"].string!.componentsSeparatedByString(":")
    let sunClose:[String]   = json["OpeningHours"]["Sunday"]["To"].string!.componentsSeparatedByString(":")

原生方式:

    var monOpen:[String] = []
    var monClose:[String] = []
    var tueOpen:[String] = []
    var tueClose:[String] = []
    var wedOpen:[String] = []
    var wedClose:[String] = []
    var thuOpen:[String] = []
    var thuClose:[String] = []
    var friOpen:[String] = []
    var friClose:[String] = []
    var satOpen:[String] = []
    var satClose:[String] = []
    var sunOpen:[String] = []
    var sunClose:[String] = []
    var openDescription:String = ""
    
    if let attractionsArray = orgJson as? NSArray{
        if let attraction = attractionsArray[0] as? NSDictionary{
            if let openHours = attraction["OpeningHours"] as? NSDictionary{
                if let day = openHours["Monday"] as? NSDictionary{
                    if let open = day["From"] as? String{
                        monOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"] as? String{
                        monClose = close.componentsSeparatedByString(":")
                    }
                }
                if let day = openHours["Tuesday"] as? NSDictionary{
                    if let open = day["From"] as? String{
                        tueOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"] as? String{
                        tueClose = close.componentsSeparatedByString(":")
                    }
                }
                if let day = openHours["Wednesday"] as? NSDictionary{
                    if let open = day["From"] as? String{
                        wedOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"] as? String{
                        wedClose = close.componentsSeparatedByString(":")
                    }
                }
                if let day = openHours["Thursday"] as? NSDictionary{
                    if let open = day["From"] as? String{
                        thuOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"] as? String{
                        thuClose = close.componentsSeparatedByString(":")
                    }
                }
                if let day = openHours["Friday"] as? NSDictionary{
                    if let open = day["From"] as? String{
                        friOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"] as? String{
                        friClose = close.componentsSeparatedByString(":")
                    }
                }
                if let day = openHours["Saturday"] as? NSDictionary{
                    if let open = day["From"] as? String{
                        satOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"] as? String{
                        satClose = close.componentsSeparatedByString(":")
                    }
                }
                if let day = openHours["Sunday"] as? NSDictionary{
                    if let open = day["From"] as? String{
                        sunOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"] as? String{
                        sunClose = close.componentsSeparatedByString(":")
                    }
                }
                if let desc = openHours["OpeningHoursGenericExceptions"] as? String{
                    openDescription = desc
                }
            }
        }
    }

这只是被解析数据的一部分，因此应用中的性能非常明显。

我想问题是，我是否错误地使用了 SwiftyJSON 还是这是预料之中的？

最佳答案

首先，你的“native way”不等同于“Swifty way”。

SwiftyJSON版本有45个subscript访问，而原生方式只有23个subscript访问。

要使“本地方式”等效，它应该是这样的:

let openDescription = attraction["OpeningHours"]!["OpeningHoursGenericExceptions"] as String
let monOpen  = (attraction["OpeningHours"]!["Monday"]!!["From"] as String).componentsSeparatedByString(":")
let monClose = (attraction["OpeningHours"]!["Monday"]!!["To"] as String).componentsSeparatedByString(":")
let tueOpen  = (attraction["OpeningHours"]!["Tuesday"]!!["From"] as String).componentsSeparatedByString(":")
let tueClose = (attraction["OpeningHours"]!["Tuesday"]!!["To"]! as String).componentsSeparatedByString(":")
// ...

或“Swifty way”应该是这样的:

let openHours = json[0]["OpeningHours"]
var day:JSON

day = openHours["Monday"]
if let open = day["From"].string {
    monOpen = open.componentsSeparatedByString(":")
}
if let close = day["To"].string {
    monClose = close.componentsSeparatedByString(":")
}
day = openHours["Tuesday"]
if let open = day["From"].string {
    tueOpen = open.componentsSeparatedByString(":")
}
if let close = day["To"].string {
    tueClose = close.componentsSeparatedByString(":")
}
// ...

无论如何，是的，SwiftyJSON 很慢。让我们测量一下:

import Foundation
import XCTest

let orgJson:AnyObject = [
    [
        "OpeningHours": [
            "OpeningHoursGenericExceptions": "test",
            "Monday":    ["From":"1:2:3","To":"1:2:3"],
            "Tuesday":   ["From":"1:2:3","To":"1:2:3"],
            "Wednesday": ["From":"1:2:3","To":"1:2:3"],
            "Thursday":  ["From":"1:2:3","To":"1:2:3"],
            "Friday":    ["From":"1:2:3","To":"1:2:3"],
            "Saturday":  ["From":"1:2:3","To":"1:2:3"],
            "Sunday":    ["From":"1:2:3","To":"1:2:3"],
        ]
    ]
]
let json = JSON(orgJson)

class JSONTestTests: XCTestCase {

    func testNativeSubscript() {
        measureBlock { () -> Void in

            for _ in 0 ..< 400 {
                autoreleasepool {
                    if let attraction = orgJson[0] as? NSDictionary {
                        let openDescription = attraction["OpeningHours"]!["OpeningHoursGenericExceptions"] as String
                        let monOpen  = (attraction["OpeningHours"]!["Monday"]!!["From"] as String).componentsSeparatedByString(":")
                        let monClose = (attraction["OpeningHours"]!["Monday"]!!["To"] as String).componentsSeparatedByString(":")
                        let tueOpen  = (attraction["OpeningHours"]!["Tuesday"]!!["From"] as String).componentsSeparatedByString(":")
                        let tueClose = (attraction["OpeningHours"]!["Tuesday"]!!["To"] as String).componentsSeparatedByString(":")
                        let wedOpen  = (attraction["OpeningHours"]!["Wednesday"]!!["From"] as String).componentsSeparatedByString(":")
                        let wedClose = (attraction["OpeningHours"]!["Wednesday"]!!["To"] as String).componentsSeparatedByString(":")
                        let thuOpen  = (attraction["OpeningHours"]!["Thursday"]!!["From"] as String).componentsSeparatedByString(":")
                        let thuClose = (attraction["OpeningHours"]!["Thursday"]!!["To"] as String).componentsSeparatedByString(":")
                        let friOpen  = (attraction["OpeningHours"]!["Friday"]!!["From"] as String).componentsSeparatedByString(":")
                        let friClose = (attraction["OpeningHours"]!["Friday"]!!["To"] as String).componentsSeparatedByString(":")
                        let satOpen  = (attraction["OpeningHours"]!["Saturday"]!!["From"] as String).componentsSeparatedByString(":")
                        let satClose = (attraction["OpeningHours"]!["Saturday"]!!["To"] as String).componentsSeparatedByString(":")
                        let sunOpen  = (attraction["OpeningHours"]!["Sunday"]!!["From"] as String).componentsSeparatedByString(":")
                        let sunClose = (attraction["OpeningHours"]!["Sunday"]!!["To"] as String).componentsSeparatedByString(":")
                        XCTAssertEqual(monOpen, ["1","2","3"], "")
                        XCTAssertEqual(openDescription, "test")
                    }
                }
            }
        }
    }

    func testJSONSubscript() {
        measureBlock { () -> Void in
            for _ in 0 ..< 400 {
                autoreleasepool {
                    let attraction = json[0]
                    let openDescription:String = attraction["OpeningHours"]["OpeningHoursGenericExceptions"].string!
                    let monOpen:[String]    = attraction["OpeningHours"]["Monday"]["From"].string!.componentsSeparatedByString(":")
                    let monClose:[String]   = attraction["OpeningHours"]["Monday"]["To"].string!.componentsSeparatedByString(":")
                    let tueOpen:[String]    = attraction["OpeningHours"]["Tuesday"]["From"].string!.componentsSeparatedByString(":")
                    let tueClose:[String]   = attraction["OpeningHours"]["Tuesday"]["To"].string!.componentsSeparatedByString(":")
                    let wedOpen:[String]    = attraction["OpeningHours"]["Wednesday"]["From"].string!.componentsSeparatedByString(":")
                    let wedClose:[String]   = attraction["OpeningHours"]["Wednesday"]["To"].string!.componentsSeparatedByString(":")
                    let thuOpen:[String]    = attraction["OpeningHours"]["Thursday"]["From"].string!.componentsSeparatedByString(":")
                    let thuClose:[String]   = attraction["OpeningHours"]["Thursday"]["To"].string!.componentsSeparatedByString(":")
                    let friOpen:[String]    = attraction["OpeningHours"]["Friday"]["From"].string!.componentsSeparatedByString(":")
                    let friClose:[String]   = attraction["OpeningHours"]["Friday"]["To"].string!.componentsSeparatedByString(":")
                    let satOpen:[String]    = attraction["OpeningHours"]["Saturday"]["From"].string!.componentsSeparatedByString(":")
                    let satClose:[String]   = attraction["OpeningHours"]["Saturday"]["To"].string!.componentsSeparatedByString(":")
                    let sunOpen:[String]    = attraction["OpeningHours"]["Sunday"]["From"].string!.componentsSeparatedByString(":")
                    let sunClose:[String]   = attraction["OpeningHours"]["Sunday"]["To"].string!.componentsSeparatedByString(":")
                    XCTAssertEqual(monOpen, ["1","2","3"], "")
                }
            }
        }
    }

    func testNativeBinding() {
        measureBlock { () -> Void in
            for _ in 0 ..< 400 {
                autoreleasepool {
                    var monOpen:[String] = []
                    var monClose:[String] = []
                    var tueOpen:[String] = []
                    var tueClose:[String] = []
                    var wedOpen:[String] = []
                    var wedClose:[String] = []
                    var thuOpen:[String] = []
                    var thuClose:[String] = []
                    var friOpen:[String] = []
                    var friClose:[String] = []
                    var satOpen:[String] = []
                    var satClose:[String] = []
                    var sunOpen:[String] = []
                    var sunClose:[String] = []
                    var openDescription:String = ""

                    if let attractionsArray = orgJson as? NSArray{
                        if let attraction = attractionsArray[0] as? NSDictionary{
                            if let openHours = attraction["OpeningHours"] as? NSDictionary{
                                if let day = openHours["Monday"] as? NSDictionary{
                                    if let open = day["From"] as? String{
                                        monOpen = open.componentsSeparatedByString(":")
                                    }
                                    if let close = day["To"] as? String{
                                        monClose = close.componentsSeparatedByString(":")
                                    }
                                }
                                if let day = openHours["Tuesday"] as? NSDictionary{
                                    if let open = day["From"] as? String{
                                        tueOpen = open.componentsSeparatedByString(":")
                                    }
                                    if let close = day["To"] as? String{
                                        tueClose = close.componentsSeparatedByString(":")
                                    }
                                }
                                if let day = openHours["Wednesday"] as? NSDictionary{
                                    if let open = day["From"] as? String{
                                        wedOpen = open.componentsSeparatedByString(":")
                                    }
                                    if let close = day["To"] as? String{
                                        wedClose = close.componentsSeparatedByString(":")
                                    }
                                }
                                if let day = openHours["Thursday"] as? NSDictionary{
                                    if let open = day["From"] as? String{
                                        thuOpen = open.componentsSeparatedByString(":")
                                    }
                                    if let close = day["To"] as? String{
                                        thuClose = close.componentsSeparatedByString(":")
                                    }
                                }
                                if let day = openHours["Friday"] as? NSDictionary{
                                    if let open = day["From"] as? String{
                                        friOpen = open.componentsSeparatedByString(":")
                                    }
                                    if let close = day["To"] as? String{
                                        friClose = close.componentsSeparatedByString(":")
                                    }
                                }
                                if let day = openHours["Saturday"] as? NSDictionary{
                                    if let open = day["From"] as? String{
                                        satOpen = open.componentsSeparatedByString(":")
                                    }
                                    if let close = day["To"] as? String{
                                        satClose = close.componentsSeparatedByString(":")
                                    }
                                }
                                if let day = openHours["Sunday"] as? NSDictionary{
                                    if let open = day["From"] as? String{
                                        sunOpen = open.componentsSeparatedByString(":")
                                    }
                                    if let close = day["To"] as? String{
                                        sunClose = close.componentsSeparatedByString(":")
                                    }
                                }
                                if let desc = openHours["OpeningHoursGenericExceptions"] as? String{
                                    openDescription = desc
                                }
                            }
                        }
                    }
                    XCTAssertEqual(monOpen, ["1","2","3"], "")
                }
            }
        }
    }
    func testJSONBinding() {
        measureBlock { () -> Void in
            for _ in 0 ..< 400 {
                autoreleasepool {
                    var monOpen:[String] = []
                    var monClose:[String] = []
                    var tueOpen:[String] = []
                    var tueClose:[String] = []
                    var wedOpen:[String] = []
                    var wedClose:[String] = []
                    var thuOpen:[String] = []
                    var thuClose:[String] = []
                    var friOpen:[String] = []
                    var friClose:[String] = []
                    var satOpen:[String] = []
                    var satClose:[String] = []
                    var sunOpen:[String] = []
                    var sunClose:[String] = []
                    var openDescription:String = ""

                    let openHours = json[0]["OpeningHours"]
                    var day:JSON

                    day = openHours["Monday"]
                    if let open = day["From"].string {
                        monOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"].string {
                        monClose
                            = close.componentsSeparatedByString(":")
                    }
                    day = openHours["Tuesday"]
                    if let open = day["From"].string {
                        tueOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"].string {
                        tueClose = close.componentsSeparatedByString(":")
                    }
                    day = openHours["WednesDay"]
                    if let open = day["From"].string {
                        wedOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"].string {
                        wedClose = close.componentsSeparatedByString(":")
                    }
                    day = openHours["Thursday"]
                    if let open = day["From"].string {
                        thuOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"].string {
                        thuClose = close.componentsSeparatedByString(":")
                    }
                    day = openHours["Friday"]
                    if let open = day["From"].string {
                        friOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"].string {
                        friClose = close.componentsSeparatedByString(":")
                    }
                    day = openHours["Saturday"]
                    if let open = day["From"].string {
                        satOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"].string {
                        satClose = close.componentsSeparatedByString(":")
                    }
                    day = openHours["Sunday"]
                    if let open = day["From"].string {
                        sunOpen = open.componentsSeparatedByString(":")
                    }
                    if let close = day["To"].string {
                        sunClose = close.componentsSeparatedByString(":")
                    }
                    XCTAssertEqual(monOpen, ["1","2","3"], "")
                }
            }
        }
    }

}

输出:

<unknown>:0: Test Case '-[JSONTestTests.JSONTestTests testJSONBinding]' measured [Time, seconds] average: 0.804, relative standard deviation: 5.592%, values: [0.835687, 0.814827, 0.819685, 0.841900, 0.764961, 0.845202, 0.691442, 0.779255, 0.818213, 0.830698], performanceMetricID:com.apple.XCTPerformanceMetric_WallClockTime, baselineName: "", baselineAverage: , maxPercentRegression: 10.000%, maxPercentRelativeStandardDeviation: 10.000%, maxRegression: 0.100, maxStandardDeviation: 0.100
<unknown>:0: Test Case '-[JSONTestTests.JSONTestTests testJSONSubscript]' measured [Time, seconds] average: 4.247, relative standard deviation: 3.496%, values: [4.019640, 4.004123, 4.146146, 4.194535, 4.487171, 4.300971, 4.310613, 4.408405, 4.318354, 4.279362], performanceMetricID:com.apple.XCTPerformanceMetric_WallClockTime, baselineName: "", baselineAverage: , maxPercentRegression: 10.000%, maxPercentRelativeStandardDeviation: 10.000%, maxRegression: 0.100, maxStandardDeviation: 0.100
<unknown>:0: Test Case '-[JSONTestTests.JSONTestTests testNativeBinding]' measured [Time, seconds] average: 0.223, relative standard deviation: 2.773%, values: [0.221099, 0.227395, 0.218860, 0.225989, 0.227128, 0.222370, 0.229956, 0.214535, 0.210818, 0.229868], performanceMetricID:com.apple.XCTPerformanceMetric_WallClockTime, baselineName: "", baselineAverage: , maxPercentRegression: 10.000%, maxPercentRelativeStandardDeviation: 10.000%, maxRegression: 0.100, maxStandardDeviation: 0.100
<unknown>:0: Test Case '-[JSONTestTests.JSONTestTests testNativeSubscript]' measured [Time, seconds] average: 0.362, relative standard deviation: 17.528%, values: [0.346285, 0.316185, 0.333650, 0.339416, 0.330243, 0.354034, 0.378730, 0.269519, 0.486904, 0.467607], performanceMetricID:com.apple.XCTPerformanceMetric_WallClockTime, baselineName: "", baselineAverage: , maxPercentRegression: 10.000%, maxPercentRelativeStandardDeviation: 10.000%, maxRegression: 0.100, maxStandardDeviation: 0.100

你的 SwiftyJSON:4.247
你的母语:0.223
我的 SwiftyJSON:0.804
我的母语:0.362

顺便说一句，如果我是你，我会这样做:

if let hours = orgJson[0]?["OpeningHours"] as? NSDictionary {
    let openDescription = hours["OpeningHoursGenericExceptions"] as? String ?? ""
    let monOpen  = hours["Monday"]?["From"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let monClose = hours["Monday"]?["To"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let tueOpen  = hours["Tuesday"]?["From"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let tueClose = hours["Tuesday"]?["To"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let wedOpen  = hours["Wednesday"]?["From"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let wedClose = hours["Wednesday"]?["To"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let thuOpen  = hours["Thursday"]?["From"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let thuClose = hours["Thursday"]?["To"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let friOpen  = hours["Friday"]?["From"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let friClose = hours["Friday"]?["To"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let satOpen  = hours["Saturday"]?["From"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let satClose = hours["Saturday"]?["To"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let sunOpen  = hours["Sunday"]?["From"]??.componentsSeparatedByString?(":") as? [String] ?? []
    let sunClose = hours["Sunday"]?["To"]??.componentsSeparatedByString?(":") as? [String] ?? []

    // ...
}

它相当快速、安全且不那么复杂。

为什么 SwiftyJSON 很慢？

在访问 subscript 时，SwiftyJSON 会:

检查 key 是 String
再次用self[key:sub]下标
检查底层对象是 NSDictionary
使用提供的键下标 NSDictionary
用结果构造JSON对象
返回

也许编译器优化了一些步骤，但是“比native慢”有些不可避免:)

关于ios - SwiftyJSON 性能问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29252158/

文章推荐： ios - Xcode 的 UML 类图(Swift 编程)

文章推荐： javascript - 'new Array' 上的 forEach 没有按照我的预期进行

文章推荐： javascript - Angularjs 在 ng-repeat 中显示和隐藏按钮

文章推荐： javascript - 过滤日期在 AngularJS 中返回 NaN-NaN-NaN

io - 内存映射 IO - IO 设备如何知道值已更改？
IO 设备如何知道属于它的内存中的值在memory mapped IO 中发生了变化？？例如，假设内存地址 0 专用于保存 VGA 设备的背景颜色。当我们更改 memory[0] 中的值时，VGA
ios - Facebook iOS iOS SDK登录错误
我目前正在开发一个使用Facebook sdk登录(通过FBLoginView)的iOS应用。一切正常，除了那些拥有较旧版本的facebook的人。当他们按下“使用Facebook登录”按钮时，他
ios - ios ios nsrange char从结束
假设我有: this - is an - example - with some - dashesNSRange将使用`rangeOfString:@“-”拾取“-”的第一个实例，但是如果我只想要最后
ios - 如何从card.io SDK获取国家名称？ -iOS
Card.io SDK提供以下详细信息: 卡号，有效期，月份，年份，CVV和邮政编码。如何从此SDK获取国家名称。 - (void)userDidProvideCreditCardInfo:(Car
ios - iOS 应用程序如何从网络服务下载图片并在安装过程中将它们安装在用户的 iOS 设备上？
iOS 应用程序如何从网络服务下载图片并在安装过程中将它们安装到用户的 iOS 设备上？可能吗？最佳答案您无法控制应用在用户设备上的安装，因此无法在安装过程中下载其他数据。只需在安装后首次启动应
ios - iOS 企业应用程序和 iOS 零售应用程序之间的区别
我曾经开发过一款企业版 iOS 产品，我们公司曾将其出售给大型企业，供他们的员工使用。该应用程序通过 AppStore 提供，企业用户获得了公司特定的配置文件(包含应用程序配置文件)以启用他们有权使
ios - Card.io ios 与本地化集成
我正在尝试将 Card.io SDK 集成到我的 iOS 应用程序中。我想为 CardIO ui 做一个简单的本地化，如更改取消按钮标题或“在此保留信用卡”提示文本。我在 github 上找到了这个
ios - Card.Io iOS 扫描名称
我正在使用 CardIOView 和 CardIOViewDelegate 类，没有可以设置为 YES 的 BOOL 来扫描 collectCardholderName。我可以看到它在 CardIOP
ios - 如何为最近的原生 ios 应用程序设置名称字段？ - iOS
我有一个集成了通话工具包的 voip 应用程序。每次我从我的 voip 应用程序调用时，都会在 native 电话应用程序中创建一个新的最近通话记录。我在 voip 应用程序中也有自定义联系人(电话应
ios - iOS 应用程序如何在应用程序打开时知道键盘是否已经在屏幕上(iOS 多任务处理)
iOS 应用程序如何知道应用程序打开时屏幕上是否已经有键盘？应用程序运行后，它可以接收键盘显示/隐藏通知。但是，如果应用程序在分屏模式下作为辅助应用程序打开，而主应用程序已经显示键盘，则辅助应用程序不
ios - iOS 上的图像 IO 错误
我在模拟器中收到以下错误: ImageIO: CGImageReadSessionGetCachedImageBlockData *** CGImageReadSessionGetCachedIm
ios - iOS 设备与非 iOS 设备通信
如 Apple 文档所示，可以通过 EAAccessory Framework 与经过认证的配件(由 Apple 认证)进行通信。但是我有点困惑，因为一些帖子告诉我它也可以通过 CoreBluetoo
ios - (iOS) 直接在 iOS 设备上查看日志消息的方式？
尽管现在的调试器已经很不错了，但有时找出应用程序中正在发生的事情的最好方法仍然是古老的 NSLog。当您连接到计算机时，这样做很容易； Xcode 会帮助弹出日志查看器面板，然后就可以了。当您不在办公
ios - Kontakt.io iOS - 按名称识别信标
在我的 iOS 应用程序中，我定义了一些兴趣点。其中一些有一个 Kontakt.io 信标的名称，它绑定(bind)到一个特定的 PoI(我的意思是通常贴在信标标签上的名称)。现在我想在附近发现信标，
ios - Trigger.io iOS 插件从回调返回数据
我正在为警报提示创建一个 trigger.io 插件。尝试从警报提示返回数据。这是我的代码: // Prompt + (void)show_prompt:(ForgeTask*)task{
ios - iOS 4、iOS 5 和 iOS 6 的推送通知有何不同？
您好，我是 Apple iOS 的新手。我阅读并搜索了很多关于推送通知的文章，但我没有发现任何关于 APNS 从 io4 到 ios 6 的新更新的信息。任何人都可以向我提供 APNS 如何在 ios
ios - iOS 8、iOS 9、iOS 10 和 iOS 11 上 UITabBar 的高度是多少？
UITabBar 的高度似乎在 iOS 7 和 8/9/10/11 之间发生了变化。我发布这个问题是为了让其他人轻松找到答案。那么:在 iPhone 和 iPad 上的 iOS 8/9/10/11
ios - 最佳实践。通过支持 iOS 5、iOS 6 和 iOS 7 UI，使 iOS 应用程序变得通用
我想我可以针对不同的 iOS 版本使用不同的 Storyboard。由于 UI 的差异，我将创建下一个 Storyboard: Main_iPhone.storyboard Main_iPad.st
ios - 如何使用 iOS 中的视觉控件在 ios 中选择音轨的一部分？
我正在写一些东西，我将使用设备的 iTunes 库中的一部分音轨来覆盖 2 个视频的组合，例如: AVMutableComposition* mixComposition = [[AVMutableC
ios - iOS 模拟器中存在头文件，但 iOS 设备上不存在...？
我创建了一个简单的 iOS 程序，可以顺利编译并在 iPad 模拟器上运行良好。当我告诉 XCode 4 使用我连接的 iPad 设备时，无法编译相同的程序。问题似乎是当我尝试使用附加的 iPad 时

IT王子

个人简介

我是一名优秀的程序员,十分优秀！

作者热门文章

滴滴打车优惠券免费领取

全站热门文章

首页

博学

6Ren·AI

商城

ios - SwiftyJSON 性能问题