ipad

When do you call the super method in viewWillAppear, viewDidDisappear, etc…?

蓝咒 提交于 2020-03-16 02:32:52
问题 In UIViewController's documentation, Apple suggests calling the super at some point in the implementation of viewWillAppear, viewDidAppear, viewWillDisappear, viewDidDisappear, etc... For example, the discussion on viewDidDisappear is: You can override this method to perform additional tasks associated with dismissing or hiding the view. If you override this method, you must call super at some point in your implementation . My question is does it matter when the super method is called and, if

When do you call the super method in viewWillAppear, viewDidDisappear, etc…?

◇◆丶佛笑我妖孽 提交于 2020-03-16 02:32:49
问题 In UIViewController's documentation, Apple suggests calling the super at some point in the implementation of viewWillAppear, viewDidAppear, viewWillDisappear, viewDidDisappear, etc... For example, the discussion on viewDidDisappear is: You can override this method to perform additional tasks associated with dismissing or hiding the view. If you override this method, you must call super at some point in your implementation . My question is does it matter when the super method is called and, if

ios8之后的界面旋转简单原理

廉价感情. 提交于 2020-03-13 20:32:27
调整约束优先级,不一定都是250.750或者1000 有时不管怎么调整,约束优先级都要大于某个值,只是焦点的俩个可以在大于某个值的范围内取大小值。 ios8之后不用interfaceOrientation属性来判断视图控制器方向,也不用willRotation方法来监测视图控制器旋转。iOS认为宽>高时为横屏,高>宽时为竖屏。因为ipad有分屏多任务的可能,可能屏幕没有旋转,但宽高大小改变,需要重新布局界面。而用- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id <UIViewControllerTransitionCoordinator>)coordinator 代替willRotataion方法,在方法里size表示要目的界面的大小,这样在屏幕旋转和屏幕没旋转但试图控制器宽高大小改变时都会走该方法。在该方法里进行相应布局就可以,iPhone和iPad都适用。需要注意的是需要先调用super 该方法。 - (void)willTransitionToTraitCollection:(UITraitCollection *)newCollection withTransitionCoordinator:(id

Easiest way to force a crash in Swift

旧街凉风 提交于 2020-03-12 09:15:32
问题 What is the easiest way to force a crash in Swift? I would like to use only one line of code (something that I can add quickly). I don't want to use breakpoints, I actually want the app to crash. 回答1: Typically you'd use fatalError() or preconditionFailure() for that. These do exactly the same: terminating the program, therefore the code after this stamement never gets executed. All of the functions that have this behaviour are annotated with the @noreturn attribute You can also do something

一个小例子讲讲jsonp

回眸只為那壹抹淺笑 提交于 2020-03-08 16:14:50
1.何为jsonp(json with padding)   json我们都知道并用过。那么jsonp呢,呃,好像听过,但没用过。很久以来楼主也只是听过这个名词而已。直到今晚楼主看到一篇文章( http://www.cnblogs.com/twobin/p/3395086.html ),然后决定探究一下什么是jsonp。   我们都知道js文件是不能跨域操作内容的,这在js里面叫做‘同源策略’,意即js文件只能操作 相同域名、相同端口、相同协议的html文档。但同时我们知道 浏览器允许跨源请求<script>资源,例如 可以通过指定<script>标签的src属性去请求其它域名的js文件,例如我们常常如此引用jquery文件,<script src = ' code.jquery.com/ jquery - latest . min.js '></script>,然后我们就能使用jquery里的方法来任意操作我们html文档里的内容了。   嗯,jsonp就是利用这一原理实现的跨域访问数据 。说白了,其实jsonp技术本质上就是创建<script>标签,并把其src指向跨域地址而实现跨域获取数据。通常的做法就是, 异步请求跨域的服务器端时,不直接返回数据而是返回一个js方法调用,将真正的数据作为该js方法调用的参数传过来。 2.jsonp实例   原理不多说

各代iPhone iPad 内部代号

南笙酒味 提交于 2020-03-04 10:27:53
程序里获取到的设变编号是iPhone的内部编号,需要做相应的转化,下面有2个地址可以取到各代iPhone iPad 内部代号: 1.iPad内部代号: https://www.theiphonewiki.com/wiki/List_of_iPads 2.IPhone内部代号: https://www.theiphonewiki.com/wiki/List_of_iPhones#iPhone_7_Plus 来源: CSDN 作者: 落难游民 链接: https://blog.csdn.net/qq243348167/article/details/104646843

How to get Current EST time IOS Swift

你离开我真会死。 提交于 2020-03-02 18:58:40
问题 I need to compare two dates in my app and i have a EST date to compare with current date , but let today = NSDate() returns the date in UTC , how can i get current EST time or convert to EST ? 回答1: The NSDate store the time in absolute moment i.e. No matter in what time zone your date was created when you use compare method of NSDate it will respect the time zone (because time zone was never stored). You can think of NSDate as epoch time which is always calculated from 00:00:00 Coordinated

UIImagePickerController not respecting video maximum duration on iPad

放肆的年华 提交于 2020-03-02 05:29:34
问题 I am trying to build an app that would let user pick and upload a video from the library on iPad. I need the max video length to be 30 sec. I am using the following code: UIImagePickerController *mediaPicker = [[UIImagePickerController alloc] init]; mediaPicker.mediaTypes = [NSArray arrayWithObjects:(NSString *)kUTTypeMovie,(NSString *)kUTTypeImage,nil]; mediaPicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum; mediaPicker.videoQuality =