UIButton，UIAlertView設置動作

Question

我有一個簡單的問題，請幫助我，因為我真的卡住了。 我需要的是，如果登錄和密碼不為空，則在按下登錄按鈕后切換到另一個ViewController

我有一個簡單的登錄界面，包括用戶名，密碼和登錄按鈕。 當密碼或登錄為空時顯示UIAlertView，這里是代碼：

.m文件

- (IBAction)login:(id)sender {
    if (userName.text.length == 0 || password.text.length == 0){
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Complete All Fields" message:@"You must complete all fields to login!" delegate:self cancelButtonTitle:@"Good" otherButtonTitles:nil, nil];
        [alert show]; 
    }
}

如何為按鈕添加動作以切換到其他UIController？ 這一個一直在粉碎[self presentModalViewController: anotherUIViewController animated YES]; 這里也是通知 - “應用程序試圖在目標上呈現一個零模態視圖控制器。”

Answer 1

根據您使用的是xib還是故事板，只保留下面解釋的其中一行。

- (IBAction)login:(id)sender {
    if (userName.text.length == 0 || password.text.length == 0){
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Complete All Fields" message:@"You must complete all fields to login!" delegate:self cancelButtonTitle:@"Good" otherButtonTitles:nil, nil];
        [alert show];
    }else{
        //if you are using xibs use this line
        UIViewController *anotherUIViewController = [[UIViewController alloc] initWithNibName:@"anotherUIViewController" bundle:[NSBundle mainBundle]];
        //
        //if you are using storyboards use this line
        UIViewController *anotherUIViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"someIdentifierForThisController"];
        //
        //then simply present the view controller
        [self presentViewController:anotherUIViewController animated:YES completion:nil];
    }
}