objective-c 实现用户验证，登陆 Xcode iOS

- (void)viewDidLoad{    [super viewDidLoad]; //加载窗口的时候把从文件里读出用户名。 NSString *filePath = [self documentsPath:@"user.txt"];     //读出文件存到数组username中    NSArray *username = [NSArray arrayWithContentsOfFile:filePath];    self.TXF1.text   = [username objectAtIndex:0];    self.Txtpwd.text = [username objectAtIndex:1];    //文本显示设为安全。星号    self.Txtpwd.secureTextEntry = YES;}
//登陆验证- (IBAction)loginpage:(id)sender {    NSLog(@"login...\n");    NSString *filePath = [self documentsPath:@"user.txt"];     //从user这个文件里读出用户名和密码是否与输入的相同    NSArray *username = [NSArray arrayWithContentsOfFile:filePath];    if([TXF1.text isEqualToString:[username objectAtIndex:0]] && [Txtpwd.text isEqualToString:[username objectAtIndex:1]])    {//如果验证正确，则重新打开一个窗口        if(self.loginhome ==nil)        {            NSLog(@"loginhome");            loginhome *homepage = [[loginhome alloc]initWithNibName:@"loginhome" bundle:nil];            self.loginhome = [homepage autorelease];            [self.view addSubview:self.loginhome.view];        }        else         {            [self.view addSubview:self.loginhome.view];        }        NSLog(@"登陆成功！\n");            }    else     {        NSLog(@"用户名或密码错误！\n");        judgelogin = [[UIAlertView alloc]initWithTitle:@"提示"                                              message:@"用户名或密码错误！"                                             delegate:self                                    cancelButtonTitle:@"取消"                                    otherButtonTitles:@"确定",nil];        [judgelogin show];        [judgelogin release];         }    }//读程序目录而准备-(NSString *)bundlePath:(NSString *)fileName {    return [[[NSBundle mainBundle] bundlePath] stringByAppendingPathComponent:fileName];}-(NSString *)documentsPath:(NSString *)fileName {    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *documentsDirectory = [paths objectAtIndex:0];    return [documentsDirectory stringByAppendingPathComponent:fileName];}-(NSString *)documentsPath {    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *documentsDirectory = [paths objectAtIndex:0];    return documentsDirectory;}