Question

我在ViewControllerLogin.m文件中或在UIAlert显示的任何地方收到此行的错误...

[UIAlertView error:@"Enter username and password over 4 chars each."];

上面的代码在问题编辑器中给出了一个错误：＆＃34;没有方法选择器的已知类＆＃34;。我确定了方法＆＃39;错误＆＃39;在Xcode的另一个类中。有谁知道我为什么会收到这个错误？

更新ViewControllerLogin.m（UIViewAlets位于底部）

#import "ViewControllerLogin.h"
#import "UIAlertView+error.h"
#import "API.h"
#include <CommonCrypto/CommonDigest.h>
#define kSalt @"adlfu3489tyh2jnkLIUGI&%EV(&0982cbgrykxjnk8855"
@implementation ViewControllerLogin
- (void)viewWillAppear:(BOOL)animated {
[self.navigationController setNavigationBarHidden:NO animated:animated];
[super viewWillAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated {
[self.navigationController setNavigationBarHidden:NO animated:animated];
[super viewWillDisappear:animated];
}
-(void)viewDidLoad {
[super viewDidLoad];
//focus on the username field / show keyboard
[fldUsername becomeFirstResponder];
[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"qwertygreen.png"] forBarMetrics:UIBarMetricsDefault];
self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName: [UIColor whiteColor]};
self.title = @"play";
//changes the buttn color
self.navigationController.navigationBar.tintColor = [UIColor whiteColor];
// Do any additional setup after loading the view.
// Do any additional setup after loading the view, typically from a nib.

}
#pragma mark - View lifecycle
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
-(IBAction)btnLoginRegisterTapped:(UIButton*)sender {
//form fields validation
if (fldUsername.text.length < 4 || fldPassword.text.length < 4)
{
    [UIAlertView error:@"Enter username and password over 4 chars each."];
    return;
}
//salt the password
NSString* saltedPassword = [NSString stringWithFormat:@"%@%@", fldPassword.text, kSalt];
//prepare the hashed storage
NSString* hashedPassword = nil;
unsigned char hashedPasswordData[CC_SHA1_DIGEST_LENGTH];
//hash the pass
NSData *data = [saltedPassword dataUsingEncoding: NSUTF8StringEncoding];
if (CC_SHA1([data bytes], [data length], hashedPasswordData)) {
    hashedPassword = [[NSString alloc] initWithBytes:hashedPasswordData length:sizeof(hashedPasswordData) encoding:NSASCIIStringEncoding];
} else {
    [UIAlertView error:@"Password can't be sent"];
    return;
}
//check whether it's a login or register
NSString* command = (sender.tag==1)?@"register":@"login";
NSMutableDictionary* params =[NSMutableDictionary dictionaryWithObjectsAndKeys:command, @"command", fldUsername.text, @"username", hashedPassword, @"password", nil];
//make the call to the web API
[[API sharedInstance] commandWithParams:params onCompletion:^(NSDictionary *json) {
    //result returned
    NSDictionary* res = [[json objectForKey:@"result"] objectAtIndex:0];
    if ([json objectForKey:@"error"]==nil && [[res objectForKey:@"IdUser"] intValue]>0) {
        [[API sharedInstance] setUser: res];
        [self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
        //show message to the user
        [[[UIAlertView alloc] initWithTitle:@"Logged in" message:[NSString stringWithFormat:@"Welcome %@",[res objectForKey:@"username"]] delegate:nil cancelButtonTitle:@"Close" otherButtonTitles: nil] show];
    } else {
        //error
        [UIAlertView error:[json objectForKey:@"error"]];
    }
}];

}

@end

Answer 1

您需要导入UIKit。

#import <UIKit/UIKit.h>

让这个UIAlert工作

1 个答案: