OC项目注意点

1、调整iOS11导航按钮间距：

- (void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    if (@available(iOS 11.0, *)) {
        [self adjustRightItemForiOS11];
    }
}

//调整iOS11导航按钮间距
- (void)adjustRightItemForiOS11{
    UINavigationItem * item=self.navigationItem;
    NSArray * array=item.leftBarButtonItems;
    if (array&&array.count!=0){
        UIBarButtonItem * buttonItem=array[0];
        UIView * view =[[[buttonItem.customView superview] superview] superview];
        NSArray * arrayConstraint=view.constraints;
        for (NSLayoutConstraint * constant in arrayConstraint) {
            if (fabs(constant.constant)==16) {
                constant.constant=0;
            }
        }
    }
}

2、转Json字符串：

+(NSString *)convertToJsonData:(NSDictionary *)dict {
    NSError *error;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:&error];
    NSString *jsonString;
    if (!jsonData) {
        NSLog(@"%@",error);
    }else{
        jsonString = [[NSString alloc]initWithData:jsonData encoding:NSUTF8StringEncoding];
        
    }
    NSMutableString *mutStr = [NSMutableString stringWithString:jsonString];
    NSRange range = {0,jsonString.length};
    
    //去掉字符串中的空格
    [mutStr replaceOccurrencesOfString:@" " withString:@"" options:NSLiteralSearch range:range];
    NSRange range2 = {0,mutStr.length};
    //去掉字符串中的换行符
    [mutStr replaceOccurrencesOfString:@"\n" withString:@"" options:NSLiteralSearch range:range2];
    return mutStr;
}

3、某个页面是否显示导航栏：

-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
    [self.navigationController setNavigationBarHidden:[viewController isKindOfClass:self.class]||[viewController isKindOfClass:yunYingViewController.class] animated:YES];
}

4、弹框再pop页面：

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
    [self.navigationController popViewControllerAnimated:YES];
});

5、根据时间戳显示时分秒：

+ (NSString *)getMMSSFromSS:(NSInteger )seconds{
    NSString *str_day = [NSString stringWithFormat:@"%ld",seconds/3600/24];
    //format of hour
    NSString *str_hour = [NSString stringWithFormat:@"%02ld",seconds/3600%24];
    //format of minute
    NSString *str_minute = [NSString stringWithFormat:@"%02ld",(seconds%3600)/60];
    //format of second
    NSString *str_second = [NSString stringWithFormat:@"%02ld",seconds%60];
    if (str_day.intValue>0) {
        return [NSString stringWithFormat:@"%@%@:%@:%@:%@",str_day,Localized(@"天"),str_hour,str_minute,str_second];
    }
    //format of time
    return [NSString stringWithFormat:@"%@:%@:%@",str_hour,str_minute,str_second];
}