viewdidunload

What works in viewDidUnload should be moved to didReceiveMemoryWarning?

由 本小妞迷上赌 提交于 2020-01-12 05:39:16
问题 In new iOS 6, viewDidUnload is deprecated and we have been instructed to use didReceiveMemoryWarning instead, to manage objects in UIViewController instances and subclasses. Is it equally effective to assign nils to UIView kinds inside didReceiveMemoryWarning like the way it has been done inside viewDidUnload ? I am asking this because these two methods seems to be working differently. It seems like didReceiveMemoryWarning doesn't guarantee viewDidLoad to be called again to re-instantiate any

【iphone】viewDidUnload 和 dealloc 的区别

由 守給你的承諾、 提交于 2019-12-26 19:08:43
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 对于iphone开发人员来说，内存管理是极为重要的技巧，哪怕程序的功能再强大，设计再漂亮，如果内存控制不好，也难逃程序莫名退出的噩运，这与网页开发是完全不同的。 内存控制里面有很多门道，在这里分析一下 viewDidUnload 和 dealloc 的区别，关于这两者的区别的文章很多，但是大都是摘抄和翻译官方文档，有的也只是简单的说两句，并没有详细说出两者具体的区别。 在了解两者之间的区别，首先要知道 view 的生命周期，google 里面有很多文章，可以先去搜一下，这里就不详解了。 顾名思义  viewDidUnload 就是当 view 被卸载以后执行的语句，它与 viewDidLoad 是相互呼应的。大家都知道官方的解释是执行类似 self.myOutlet = nil; 的命令，但是为什么这么干，什么时候调用这个方法呢? 这个方法是不能手动调用的，它实际上是当应用程序接收到手机内存警告的时候自动调用的方法，目的就是清空内存除当前 viewController 以外所有已经加载过的 viewController 里面的暂时不再使用的一些控件或数据，以避免应用程序应消耗内存过多被强制关闭。记住，是除当前正在展示的 view 所属 viewController 以外所有已经在内存里面的

Cordova iOS custom Plugin : handle memory warning

由 和自甴很熟 提交于 2019-12-23 23:19:31
问题 I'm developing an iOS app that use cordova(2.1), and some custom plugins. The problem that I'm trying to face is the following : When I show my plugin(basically a camera plugin with more features than the built-in cordova plugin) sometime I receive a memory warning and a consequent unload of the view containing the webview. This is a really huge issue for me because once my imagePicker is dismissed the webview is not restored. I had a look at the CDVCamera plugin source and what I noted is

iPhone - How to deal with low memory conditions

由 烈酒焚心 提交于 2019-12-22 14:42:34
问题 When the app receives a low memory warning message, 3 situations can happen : your app has just been launched and the user has not done anything special the app is running and there is a current context the app is in the background with some running context So when you receive this message, your are supposed to free memory... But where ? And how ? I understand that : initWith ..... must set the default static values. viewDidLoad must load any non static object didReceiveMemoryWarning must

Do I need to call [super viewDidUnload]?

由 和自甴很熟 提交于 2019-12-21 17:26:50
问题 I have seen some Apple examples that do call [super viewDidUnload]; and some that don't. I read an article (a few months ago so I dont recall the url) that said calling [super viewDidUnload]; was unnecessary but it didn't explain beyond that. Is there a definitive reason why or why not to tell super that the viewDidUnload ? And, (if it should be done) do I call super before setting all my properties to nil , after, or does it matter? - (void)viewDidUnload { // Is this necessary? // [super

The right place to call .removeObserver for NSNotificationCenter = Swift deinit()?

由 只愿长相守 提交于 2019-12-12 10:34:22
问题 I've read a lot of suggestions for the right place to call .removeObserver for NSNotificationCenter since viewDidUnload is not an option. I was just wondering if the new deinit() in Swift would be a good choice? -nick 回答1: It really depends on the role of the class where you subscribe to NSNotificationCenter notifications. If you are subscribing in: UIView Then you should unsubscribe as soon as view gets invisible to the user. To save CPU cycles and not consume resources while user does not

Best practices for releasing retained views?

由 前提是你 提交于 2019-12-10 06:58:00
问题 Is this the correct (best?) way to release views retained in viewDidLoad , in iOS 4.x or lower? Is there anything else to consider? - (void) viewDidUnload { [super viewDidUnload]; [self releaseViews]; } - (void) dealloc { [self releaseViews]; [super dealloc]; } #define SAFE_RELEASE(a) [a release]; a = nil; - (void) releaseViews { SAFE_RELEASE(myView1); SAFE_RELEASE(myView2); SAFE_RELEASE(myView3); } 回答1: The -dealloc is correct and the -viewDidUnload will work, but typically retained views

viewDidUnload not called for alloc/init initialized viewcontroller with no xib file

由 此生再无相见时 提交于 2019-12-08 11:13:17
问题 Why isn't viewDidUnload method called, when I'm not using xib and use alloc/init to initialize my ViewController when i simulate memory warning for any iOS version via Simulator? It seems as if this method is never called. If I create controller via alloc/initWithNibName with xib file, viewDidUnload method successfully called. Why does it happend? Does xib file is reqired for all viewcontrollers to normal handling of memory warnings? 回答1: viewDidUnload is called whenever a memory warning is

iPhone - How to deal with low memory conditions

由 吃可爱长大的小学妹 提交于 2019-12-06 06:09:09
When the app receives a low memory warning message, 3 situations can happen : your app has just been launched and the user has not done anything special the app is running and there is a current context the app is in the background with some running context So when you receive this message, your are supposed to free memory... But where ? And how ? I understand that : initWith ..... must set the default static values. viewDidLoad must load any non static object didReceiveMemoryWarning must free those non static objects I don't see what can/must be done in viewDidUnload ... I guess some retained

Do I need to call [super viewDidUnload]?

由 独自空忆成欢 提交于 2019-12-04 09:31:26
I have seen some Apple examples that do call [super viewDidUnload]; and some that don't. I read an article (a few months ago so I dont recall the url) that said calling [super viewDidUnload]; was unnecessary but it didn't explain beyond that. Is there a definitive reason why or why not to tell super that the viewDidUnload ? And, (if it should be done) do I call super before setting all my properties to nil , after, or does it matter? - (void)viewDidUnload { // Is this necessary? // [super viewDidUnload]; self.tableDataSource = nil; self.titleLabel = nil; // Is it better to call super before or
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