iOS5中的UIAlertView

iOS5中提供了几种便利的UIAlertView，如下所示：

- (IBAction)showDefaultAlertView:(id)sender {    
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"DefaultStyle" 
                                                        message:@"the default alert view style"
                                                       delegate:self 
                                              cancelButtonTitle:@"Cancel" 
                                              otherButtonTitles:@"OK", nil];    
    [alertView show];
    [alertView release];
}

- (IBAction)showSecureTextAlertView:(id)sender {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"SecureTextStyle" 
                                                        message:@"Enter secure text"
                                                       delegate:self 
                                              cancelButtonTitle:@"Cancel" 
                                              otherButtonTitles:@"OK", nil];    
    alertView.alertViewStyle = UIAlertViewStyleSecureTextInput;
    [alertView show];
    [alertView release];
}

- (IBAction)showPlainTextAlertView:(id)sender {    
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"PlainTextStyle" 
                                                        message:@"Enter plain text"
                                                       delegate:self 
                                              cancelButtonTitle:@"Cancel" 
                                              otherButtonTitles:@"OK", nil];    
    alertView.alertViewStyle = UIAlertViewStylePlainTextInput;
    [alertView show];
    [alertView release];
}

- (IBAction)showLoginPassAlertView:(id)sender {    
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"LoginAndPaswordStyle" 
                                                        message:@"Enter login and password"
                                                       delegate:self 
                                              cancelButtonTitle:@"Cancel" 
                                              otherButtonTitles:@"OK", nil];    
    alertView.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput;
    [alertView show];
    [alertView release];
}

下面是对应的代理方法：

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
    switch (alertView.alertViewStyle) {
        case UIAlertViewStylePlainTextInput:
        {
            UITextField *textField = [alertView textFieldAtIndex:0];
            NSLog(@"Plain text input: %@", textField.text);
        }
            break;
            
        case UIAlertViewStyleSecureTextInput:
        {
            UITextField *textField = [alertView textFieldAtIndex:0];
            NSLog(@"Secure text input: %@", textField.text);
        }
            break;
            
        case UIAlertViewStyleLoginAndPasswordInput:
        {
            UITextField *loginField = [alertView textFieldAtIndex:0];
            NSLog(@"Login input: %@", loginField.text);
            
            UITextField *passwordField = [alertView textFieldAtIndex:1];
            NSLog(@"Password input: %@", passwordField.text);
        }
            break;
            
        default:
            break;
    }
}

- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView {
    UIAlertViewStyle style = alertView.alertViewStyle;
    
    if ((style == UIAlertViewStyleSecureTextInput) ||
        (style == UIAlertViewStylePlainTextInput) ||
        (style == UIAlertViewStyleLoginAndPasswordInput)) {
        UITextField *textField = [alertView textFieldAtIndex:0];
        if ([textField.text length] == 0) {
            return NO;
        }
    }
    
    return YES;
}