我可以在不使用objectAtIndex的情况下读取视图控制器吗？

Question

目标：当我触摸“fourthViewController”按钮时，它会检查“secondViewController”是否放在viewController堆栈中，而不使用“objectAtIndex：x”。如果存在，它会弹出视图控制器，直到第二个ViewController位于顶部。

目前的结果：

2014-03-11 10:44:54.187 Test_Push[320:11303] (
"<HomeViewController: 0x7153bd0>",
"<secondViewController: 0x71636c0>",
"<thirdViewController: 0x71648e0>",
"<fourthViewController: 0x7128b60>"
)

Answer 1

我不完全确定我理解你的要求，但是如果你想检查secondViewController是否在viewControllerStack中，请执行以下操作：

NSArray * viewControllerStack = // I'm assuming you have array here

if ([viewControllerStack containsObject:secondViewController]) {
    // 'secondViewController' in viewControllerStack
    // Pop secondViewController here
}
else {
    // 'secondViewController' NOT in viewControllerStack
    // do other stuff
}

Answer 2

试试这个，

for (UIViewController *viewcontroller in [self.navigationController viewControllers]) {
    if ([viewcontroller isKindOfClass: [secondViewController class]]){

        [self.navigationController popToViewController:viewcontroller animated:YES];
    }
}   

Answer 3

尝试这些解决方案：

for(int i=0;i<[[self.navigationController viewControllers]count];i++)
{
    NSLog(@"%@",[[self.navigationController viewControllers]objectAtIndex:i]);

    if([[[self.navigationController viewControllers]objectAtIndex:i] isKindOfClass:[secondViewController class]]){

        [[self navigationController]popToViewController:[[self.navigationController viewControllers]objectAtIndex:i] animated:YES];

    }