小编Gra*_*ell的帖子

如何限制UITextField除点和下划线之外的特殊字符？

我已经尝试了下面的代码片段,但没有运气:

#define ACCEPTABLE_CHARECTERS @" ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_."

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
         NSCharacterSet *acceptedInput = [NSCharacterSet characterSetWithCharactersInString:ACCEPTABLE_CHARECTERS];
        if (![[string componentsSeparatedByCharactersInSet:acceptedInput] count] > 1){
            NSLog(@"not allowed");
            return NO;
        }
        else{
            return YES;
        }
}

什么是iPhone 5的图像命名约定,如@ 2x用于视网膜屏幕.

嗨,我正在使用MFMessageComposeViewController在我的iOS项目中发送短信,我的代码如下所示,

 MFMessageComposeViewController *message = [[MFMessageComposeViewController alloc] init];
    message.delegate = self;
    message.recipients = [NSArray arrayWithObject:@"xxxxxx"];
    message.body = @"blha blah,,,,";
    [self presentModalViewController:message animated:YES];

并且在我的代码中我定义了MFMessageComposeViewControllerDelegate方法didFinishWithResult但是当任务完成时,控件没有调用这个didFinishWithResult委托方法.可能是什么问题？

任何帮助都提前感谢.

ObjectiveC中b/w imageNamed和imageWithContentsOfFile有什么区别

我正在为我的应用程序编写一个单独的NSObject类,用于WebService调用,所以我有一个混乱,我需要明确编写init方法,如下所示,

-(id)init{
    self = [super init];
    return self;
}

或者即使我忽略了这一点并尝试从另一个类调用它会工作吗？

任何人都可以告诉块动画相当于下面的代码片段吗？

[UIView beginAnimations:@"View Flip" context:nil];
[UIView setAnimationDuration:0.75];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight 
           forView:self.navigationController.view cache:NO];

NextViewController *next = [[NextViewController alloc] 
           initWithNibName:@"NextViewController" bundle:nil];

[self.navigationController pushViewController:next animated:YES];
[next release];
[UIView commitAnimations];

我从服务器数据中获取UTF8编码数据就好Less%20than%20100但我需要这些数据Less than 100(解码格式),我的NSXMLParsing委托方法就像

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName 
  namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName 
    attributes:(NSDictionary *)attributeDict {
if([elementName isEqualToString:@"option"]) {

            dict = [[NSMutableDictionary alloc]init];
            [dict setValue:[attributeDict objectForKey:@"text"] forKey:@"text"];/* Here itself i need to decode & save in to my dict */
}

如何解码这些数据.

在启用ARC的项目中,我可以在self中使用的等效关键字是什么？例如:[self mymethod]; 什么是ARC等效的这种方法调用？

我在我的代码中使用NSDictionary的writeToFile属性我正在尝试将字典更新到文档目录,如下所示,

NSDictionary *revisionDict = [NSDictionary dictionaryWithObject:currentItem.rev forKey:destPath];
NSArray *documentDirPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentDirPath objectAtIndex:0];
NSString *dictPath = [documentsDir stringByAppendingPathComponent:@"Revision.dictionary"];
[revisionDict writeToFile:dictPath atomically:YES];

这里的问题是我的字典,而不是每次迭代都被新条目更新,它会被新条目所覆盖.如何更新我的字典是否有任何替代writeToFile,任何帮助提前赞赏.

嗨我使用下面的代码将截图附加到mailcomposer,我没有设备检查所以这将在实际设备上工作？

-(void)launchMailAppOnDevice
{
    /*Take a SnapShot of current screen*/
    UIGraphicsBeginImageContext(self.view.frame.size);
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    NSData * imageData = UIImageJPEGRepresentation(image, 1.0);

    NSString *recipients = @"mailto:xyz@abc.com?cc=@\"\"&subject=blah!!blah!!";

    NSString *body = @"&body=blah!!blah!!";

    NSString *email = [NSString stringWithFormat:@"%@%@%@", recipients, body,  imageData];
    email = [email stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:email]];
}