应用程序视图似乎在一段时间后重新加载回默认值

I've come across a strange error while programming my iPhone application. Basically when I leave my application in the background and then access it after a long time (i.e. the entire night while I'm sleeping), the viewDidLoad method seems to be called again even though I did not exit the app (I only double tapped the Home button or I tapped the Home button once) but still left the app in the background. However, if I leave the app on for a short period of time (anytime between a few minutes to a few hours), the viewDidLoad method is not called again and everything is as it should be. After doing some research, I found that it is because the viewDidUnload method is called (after the OS finds that the app is suspended for a long time), which calls viewDidLoad again when we bring the app back up. I found this out through this link: view seems to reload itself but it doesn't seem that there's a way to prevent viewDidLoad from being called when the viewDidUnload is called. Is there any way to prevent this viewDidUnload method from being called again? The thing is I want my app to be running for a long time in the background (i.e. a few days in the background) to collect data. Or, is there no way around this? Any help would be appreciated. Thanks!

我在编写iPhone应用程序时遇到了一个奇怪的错误。基本上当我将我的应用程序留在后台然后在很长一段时间后访问它（即我正在睡觉的整个晚上）时，即使我没有退出应用程序，我也会再次调用viewDidLoad方法（我只是双击主页按钮或我点击主页按钮一次）但仍然在后台留下应用程序。但是，如果我在短时间内（几分钟到几个小时之间的任何时间）启动应用程序，则不会再次调用viewDidLoad方法，一切都应该如此。在做了一些研究后，我发现这是因为调用了viewDidUnload方法（在操作系统发现应用程序被暂停了很长时间之后），当我们重新启动应用程序时再次调用viewDidLoad。我通过这个链接找到了这个：视图似乎重新加载自己，但似乎没有办法阻止在调用viewDidUnload时调用viewDidLoad。有没有办法阻止再次调用viewDidUnload方法？问题是我希望我的应用程序在后台运行很长时间（即在后台几天）来收集数据。或者，有没有办法解决这个问题？任何帮助，将不胜感激。谢谢！

EDIT: I have realized that after iOS 5, viewDidUnload is deprecated but this phenomenon still occurs. Any ideas on how to fix it? Thanks!

编辑：我已经意识到在iOS 5之后，不推荐使用viewDidUnload，但这种现象仍然存在。关于如何修复它的任何想法？谢谢！

1 个解决方案

#1

If you want to do stuff in the background you should look into background tasks.

如果你想在后台做事，你应该研究后台任务。