cell.textLabel.textAlignment = UITextAlignmentCenter;

现在我想写cell.textLabel.textAlignment =NSTextAlignmentCenter;

UITableViewCell *cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:nil] autorelease];

须要写成

static NSString *TableSampleIdentifier =@"TableSampleIdentifier";

UITableViewCell *cell = [[UITableViewCellalloc]initWithStyle:UITableViewCellStyleValue1reuseIdentifier:TableSampleIdentifier];

[selfpresentModalViewController:calendarViewanimated:YES];

改成  [selfpresentViewController:calendarViewanimated:YEScompletion:^{}];

新接口的区别是提供了一个參数，同意你传入一个block。这个block的回调方法在VC的viewWillDisappear方法后调用。也就是被隐藏的VC对象被释放后执行回调。

这样做的优点：能够方便做多个UI效果之间的衔接和转换。

在IOS7的PageControl控件

调用[self.subviewsobjectAtIndex:i]

取出的不是UIImageView而是UIView

所以updateDots方法应该这样写:

-(void) updateDots{

    for (int i = 0; i < [self.subviews count]; i++) {

        UIView* dotView = [self.subviews objectAtIndex:i];

        if ([dotView isKindOfClass:[UIImageView class]]) {

            UIImageView* dot = (UIImageView*)dotView;

            if (i == self.currentPage)

                dot.image = _activeImage;

            else

                dot.image = _inactiveImage;

        }else{

            if (i == self.currentPage)

                [dotView setBackgroundColor:[UIColor colorWithPatternImage:_activeImage]];

            else

                [dotView setBackgroundColor:[UIColor colorWithPatternImage:_inactiveImage]];

        }

    }

}

[text drawAtPoint:textPt
withFont:[UIFontsystemFontOfSize:14.0f]]

在IOS7中应该写

 #define NLSystemVersionGreaterOrEqualThan(version)  ([[[UIDevice currentDevice] systemVersion] floatValue] >= version)

    #define IOS7_OR_LATER   NLSystemVersionGreaterOrEqualThan(7.0)

    if (IOS7_OR_LATER) {

        UIFont* font = [UIFont preferredFontForTextStyle:UIFontTextStyleBody];

        font = [font fontWithSize:14.0f];

        [text drawAtPoint:textPt withAttributes:@{NSFontAttributeName:font}];

    }else {

        [text drawAtPoint:textPt withFont:[UIFont systemFontOfSize:14.0f]];

    }