[英]Presenting new view controller from alert view handler displays black screen
我有一個PasswordViewController,如果我輸入了錯誤的用戶名或密碼,會提示我,但是當按下Enter按鈕時,我無法讓它加載AdminViewController
。 它會顯示黑屏。
PasswordViewController.h
#import <UIKit/UIKit.h>
#import "AdminViewController.h"
@interface PasswordViewController : UIViewController
@property (strong, nonatomic) IBOutlet UITextField *username;
@property (strong, nonatomic) IBOutlet UITextField *password;
- (IBAction)enterButton:(id)sender;
@end
NSDictionary *passwordDictionary;
PasswordViewController.m
#import "PasswordViewController.h"
@interface PasswordViewController ()
@end
@implementation PasswordViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
passwordDictionary = [[NSDictionary alloc] initWithObjects:[NSArray arrayWithObjects:@"password", nil] forKeys:[NSArray arrayWithObjects:@"username", nil]];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)enterButton:(id)sender {
if ([[passwordDictionary objectForKey:_username.text]isEqualToString:_password.text]) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Correct Password" message:@"This password is correct." delegate:self cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
[alert show];
AdminViewController *secondView = [[AdminViewController alloc] init];
[self presentViewController:secondView animated:YES completion:nil];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Incorrect Password" message:@"This password is incorrect" delegate:self cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
[alert show];
}
}
@end
AdminViewController.h
@interface AdminViewController : UIViewController
@property (strong, nonatomic) IBOutlet UIWebView *webView;
@end
AdminViewController.m
#import "AdminViewController.h"
@interface AdminViewController ()
@end
@implementation AdminViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
NSURL *myURL = [NSURL URLWithString:@"http://www.google.co.uk"];
NSURLRequest *myRequest = [NSURLRequest requestWithURL:myURL];
[_webView loadRequest:myRequest];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
您的PasswordViewController需要符合UIAlertViewDelegate
在這種方法中:
是您應該啟動AdminViewController的地方。
好的問題解決了! 我是從PasswordViewController上的Enter按鈕按Ctrl +拖動到AdminViewController,然后選擇Push Segue而不是從實際ViewController本身按Ctrl +拖動。 然后,我不得不設置一個Segue標識符。 當我這樣做時,我能夠使用以下代碼來獲得所需的結果:
- (IBAction)enterButton:(id)sender {
if ([[passwordDictionary objectForKey:_username.text]isEqualToString:_password.text]) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Correct Password" message:@"This password is correct." delegate:self cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
[alert show];
[self performSegueWithIdentifier:@"passwordAccepted" sender:self];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Incorrect Password" message:@"This password is incorrect" delegate:self cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
[alert show];
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.