iOS内存警告案例崩溃并出现错误"message sent to deallocated instance"

Question

将我的视图控制器两次推送到导航控制器并模拟内存警告，导致应用程序崩溃并出现错误:"message sent to deallocated instance"

我通过按下按钮来推动视图控制器:

-(void)buttonPressed
{
    MyViewCOntroller *vc = [[MyViewController alloc] init];
    [self.navigationController pushViewController:vc animated:YES];
}

场景:

1. [self buttonPressed];
2. 在vc中按后退键
3. [self buttonPressed];
4. 在vc中按后退键
5. 模拟内存警告

如果只按一次，不会发生崩溃。

我也试图移动"vc"的父控制器的ivar，但效果是相同的…

也许这将帮助，但我使用自定义后退按钮和它的选择器:

-(void)backButtonPressed
{
    [self.navigationController popViewControllerAnimated:YES];
}

Answer 1

创建vc对象作为类成员并检查是否存在crash

 @interface ParentViewController()
 {
    MyViewCOntroller *vc;
 }
 @end
 @implementation PaintingViewController

  -(void)buttonPressed
  {
     vc = [[MyViewController alloc] init];
     [self.navigationController pushViewController:vc animated:YES];
  }

Answer 2

找到解决方案了。请看我对另一个问题的回答:

[UINavigationController retain]:消息发送到已分配的实例