Question

我正在尝试在故事板中以编程方式更改标签但是收到错误

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];

TabViewController *tabBarCon = [storyboard 
                            instantiateViewControllerWithIdentifier:@"tabBar"];

tabBarCon.selectedViewController = [tabBarCon.viewControllers objectAtIndex:1];

错误

由于未捕获的异常终止应用程序＆＃39; NSInvalidArgumentException＆＃39;，原因：＆＃39; *** - [__ NSArrayM insertObject：atIndex：]：对象不能为零

此处tabBarCon.viewControllers不为空。

NSLog(@"%@",tabBarCon.viewControllers);给予

(
"<FirstViewController: 0x16642020>",
"<SecondViewController: 0x173c4c00>",
"<ThirdViewController: 0x166db570>",
"<ForthViewController: 0x166d17c0>",
"<FifthViewController: 0x166066a0>"
)

Answer 1

你需要有tabbarcontroller的实例。

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];

TabViewController *tabBarCon = [storyboard instantiateViewControllerWithIdentifier:@"tabBar"];

此语句从故事板创建tabbar的新实例。

[self.tabBarController setSelectedIndex:1];

如果您位于标签栏控制器内，那么您可以使用self.tabBarController

轻松获取实例

Answer 2

试试这个：

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
TabViewController *tabBarCon = [storyboard                            instantiateViewControllerWithIdentifier:@"tabBar"];
[self.tabBarController setSelectedIndex:1];

Answer 3

试试这个

UITabBarController *controller =(UITabBarController *)     
self.window.rootViewController;
[controller setSelectedIndex:1];

我试过Appdelegate它正在运作

iOS：以编程方式更改标签 - 故事板

3 个答案: