小编bog*_*gen的帖子

当我设置navigationController.hidesBarOnSwipe = YES并尝试在显示的webView中滑动时,导航栏被隐藏,但当我尝试滑动以将其取回时,它将永远不会再出现.

我的ViewController正在监听滑动事件:

[self.navigationController.barHideOnSwipeGestureRecognizer addTarget:self action:@selector(swipe:)]?

但是,由于滑动隐藏了导航栏,因此实际上从未再次调用此选择器.谁实施了hidesBarOnSwipe？它是一个已知的错误还是它的设计,它隐藏后不会显示导航栏.

之前:

后:

我有这个枚举:

typedef types {
    HBIntineraryTypeVisited = 0,
    HBIntineraryTypeUnvisited,
    HBIntineraryTypeUnknown,
    HBIntineraryTypeDeleted,
} HBIntineraryType;

并希望使用nscoding协议将其与其他一些变量一起存储

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super init];
    if (self) {
       _name = [aDecoder decodeObjectForKey:@"name"];
       // todo decode enum object
    }
}

- (void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeObject:_name forKey:@"name"];
    // todo encode enum object
}

我使用什么编码器方法来解码和编码这种枚举？

protocol Car {
    static func foo() 
}

struct Truck : Car {

}

extension Car {
    static func foo() {
        print("bar")
    }
}

Car.foo() // Does not work  
// Error: Car does not have a member named foo

Truck.foo() // Works

Xcode Car.foo()正确地自动填充,所以我要问的是它是否是一个不能编译的错误(说它没有一个名为foo()的成员).如果在协议扩展中定义静态方法,可以直接在协议上调用静态方法吗？

protocol LazyUpdateable {
    func waitToDoStuff()
    func myMethodName()
}


extension LazyUpdateable where Self: NSObject {
    func waitToDoStuff() {
        self.performSelector(#selector(myMethodName), withObject: nil, afterDelay: 1.5)
    }

    func myMethodName() {

    }
}

有了这个更新,我得到了错误Argument of #selector refers to a method that is not exposed to objective c,但是如果我继续使用旧版本,Selector("myMethodName")我会收到警告,要求更改为更好的方法.#selector()在这种情况下是否可以使用？它不适用于设置@objc我的协议,我已经尝试过了.

这是一个你可以尝试的游乐场,它表明它不适用于设置 @objc

import Foundation
import UIKit
import XCPlayground


@objc protocol LazyUpdatable {
    optional func waitToDoStuff()
    optional func myMethodName()
}

extension LazyUpdatable where Self: UIViewController {
    func waitToDoStuff() {
        self.performSelector(#selector(myMethodName), withObject: …

我有一个方法的子集,需要获得当月的第一天.

NSDate *today = [NSDate date];  // returns correctly 28 february 2013
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [[NSDateComponents alloc] init];
components.day = 1;
NSDate *dayOneInCurrentMonth = [gregorian dateByAddingComponents:components toDate:today options:0];

dayOneInCurrentMonth然后打印出来2013-03-01 09:53:49 +0000,下个月的第一天.

我如何获得当月的第一天？

我在github上托管了一些开源代码,用于向UITextField添加基于块的类别.我添加了一个.travis.yml文件来让travis CI在每次推送时构建和运行代码.链接到Travis CI警告.它成功地构建了该项目.运行.travis.yml脚本时收到的警告是:

WARNING: Using Objective-C testing without specifying a scheme and either
a workspace or a project is deprecated.

我想运行的示例项目位于文件夹/ UITextView Blocks示例/如何添加到.travis.yml文件以运行此项目？我的travis.yml文件现在由

language: objective-c

我有一个包含AFHTTPSessionManager*fileTransferSessionManager的单例类.在其中我有时想要取消所有下载,在重新开始之前,这是通过downloadTasks运行并取消它们.问题是,当调用downloadtasks属性时,如果有正在运行的下载,则主线程会冻结.

// My method canceling download tasks:
NSArray *downloadTasks =  self.fileTransferSessionManager.downloadTasks;   
for (NSURLSessionDownloadTask *downloadTask in downloadTasks) {
     [downloadTask cancel];
}

// In AFURLSessionManager.m
- (NSArray *)downloadTasks {
    return [self tasksForKeyPath:NSStringFromSelector(_cmd)];
}

调用冻结主线程的方法,因为从不调用带有dispatch_semaphore_signal(信号量)的getTasksWithCompletionHandler:

// In AFURLSessionManager.m
- (NSArray *)tasksForKeyPath:(NSString *)keyPath {
    __block NSArray *tasks = nil;
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
    [self.session getTasksWithCompletionHandler:^(NSArray *dataTasks, NSArray *uploadTasks, NSArray *downloadTasks) {
        if ([keyPath isEqualToString:NSStringFromSelector(@selector(dataTasks))]) {
            tasks = dataTasks;
        } else if ([keyPath isEqualToString:NSStringFromSelector(@selector(uploadTasks))]) {
            tasks = uploadTasks;
        } else if ([keyPath isEqualToString:NSStringFromSelector(@selector(downloadTasks))]) {
            tasks …

stringWithFormat应该返回一个字符串,为什么这个语句不能编译

NSAssert(YES, [NSString stringWithFormat:@"%@",@"test if compiles"]);

什么时候

NSAssert(YES, @"test if compiles");

编译？

class OAuthToken: NSObject, NSCoding {

var refreshToken: String?
var accessToken: String?
var scope: String?

convenience init?(refreshToken: String?, accessToken: String?, scope:String) {
    self.init()

    if let acutalRefreshToken = refreshToken as String? {
        self.refreshToken = acutalRefreshToken
    } else {
        return nil
    }
    if let actualAccessToken = accessToken as String? {
        self.accessToken = actualAccessToken
    }else {
        return nil
    }
    self.scope = scope
}

convenience init?(attributes: Dictionary<String,AnyObject>, scope: String) {
    var aRefreshToken: String!
    var anAccessToken: String?
    aRefreshToken = attributes["refresh_token"] as String?
    anAccessToken = attributes["access_token"] as …

let expecation = expectationWithDescription("do tasks")
for i in 0...40 {

    let afterTiming = 0.3 * Double(i)
    let startTime = CFAbsoluteTimeGetCurrent()

    let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(afterTiming * Double(NSEC_PER_SEC)))

    dispatch_after(delayTime, dispatch_get_main_queue()) {
        let timeElapsed = CFAbsoluteTimeGetCurrent() - startTime
        print("\(afterTiming) - \(timeElapsed) : \(i)")
    }
}

waitForExpectationWithTimeout(14)

在30执行它几乎一秒钟之后,控制台开始表现奇怪,同时显示两条和两条打印线

9.0 - 9.88806998729706 : 30
9.3 - 9.88832598924637 : 31

有没有办法XCTest让我们更接近"在正确的时间"实际执行请求？就像在9.88秒后没有完成9秒后应该完成的请求一样.