释放UINavigationController内部的ViewControllers表单内存 [英] Releasing ViewControllers form memory inside a UINavigationController

问题描述

我正在使用UINavigationController构建应用.我有一个ViewController，它显示了一些内容，当它收到用户的交互(例如，点击按钮)时，将显示一个新的ViewController.

I'm building an app using a UINavigationController. I have a ViewController that shows some content, and when it receives interaction from the user (tapping a button for example) a new ViewController is displayed.

这是代码:

FirstViewController.m

-(IBAction)goToSecondVC:(id)sender{  
    SecondViewController *secondVC = [[SecondViewController alloc] init];
    [self.navigationController pushViewController: secondVC];    
}

我想在SecondViewController出现后从内存中释放FirstViewController.然后例如，如果我从SecondViewController跳到FifthViewController，我也希望发布SecondViewController. 当我在控制器之间来回跳转时，应用程序消耗的内存增加了，这意味着它们没有被释放.有什么想法吗?

I want to release FirstViewController from memory once SecondViewController has appeared. And then for example, if I jump from SecondViewController to FifthViewController I'd like SecondViewController to be released as well. The memory consumed by the app increases when I jump back and forth between controllers, meaning that they are not being released. Any thoughts?

当我在控制器之间切换时，内存指示器会发生这种情况. ARC已激活:

This is what happens with the memory indicator when I switch between controllers. ARC is activated:

推荐答案

UINavigationController使用堆栈数据结构来管理viewControllers，因此您有2个操作:Pop和Push. firstVC --push-> secondVC --push-> thirdVC.现在，第一，第二和第三将保留在内存中，以便更快地弹出.如果您认为这会占用大量内存，而您无法为viewController使用其他演示文稿，例如以模态方式呈现它，或将其添加为已编译的viewController，然后手动将其删除，但使用UINavigationController，则仅执行pop操作将确保viewController将被释放(如果没有其他强大的引用).

UINavigationController uses stack data structure to mange viewControllers, so you have 2 operations: Pop and Push. firstVC --push-> secondVC --push-> thirdVC. now first, second and third will stay in memory for faster popping. If you think that this consume a lot of memory than you can use other presentations for your viewController, for example modally presenting it, or adding it as a chiled viewController and then remove it manually, but with UINavigationController, only pop operation will ensure that the viewController will be released (if no other strong references on it).

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