小编fib*_*chi的帖子

我想要一个只接受从0到9和减号的浮点数的正则表达式.

请帮忙.

我使用外观代理自定义导航栏中的后退按钮,还设置图像和文本属性.一切正常,但后退按钮中的文字不是中心对齐的.

这是我的代码.

UIBarButtonItem *backButton = [[[UIBarButtonItem alloc] initWithTitle:title style:UIBarButtonItemStyleBordered target:nil action:nil] autorelease];
 UIImage *buttonBack32 = [[UIImage imageNamed:@"NavigationBackButton"] 
                         resizableImageWithCapInsets:UIEdgeInsetsMake(0, 10, 0, 5)];

[[UIBarButtonItem appearance] setBackButtonBackgroundImage:buttonBack32 forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
 [[UIBarButtonItem appearance] setTitleTextAttributes:
 [NSDictionary dictionaryWithObjectsAndKeys:
        [UIColor whiteColor], 
        UITextAttributeTextColor, 
        [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.8], 
        UITextAttributeTextShadowColor, 
        [NSValue valueWithUIOffset:UIOffsetMake(0, -1)], 
        UITextAttributeTextShadowOffset,
  [UIFont fontWithName:@"xxx" size:16.0], 
  UITextAttributeFont,
  nil] 
                                            forState:UIControlStateNormal]; 
self.navigationItem.backBarButtonItem = backButton;

如果我将字体大小设置为"0.0",则文本的大小会变得太小而且仍然没有居中对齐.

在此先感谢您的帮助.

我有这段代码创建自定义UISlider.当我快速滑动到最后时,left_image.png没有显示,但如果我不滑动,它工作正常.

[sliderFPS setMinimumTrackImage:[UIImage imageNamed:@"left_slider.png"]
                       forState:UIControlStateNormal];
[sliderFPS setMaximumTrackImage:[UIImage imageNamed:@"right_slider.png"]
                       forState:UIControlStateNormal];

[sliderFPS setThumbImage:[UIImage imageNamed:@"thumb_slider.png"]      
                forState:UIControlStateNormal];

我花了2个多小时但找不到任何解决方案.任何帮助都会受到太多赞赏.