双击UITabBarItem以像Twitter应用程序一样向上滚动和重新加载

Question

如何在UITabBarItem上实现双击,以便它可以向上滚动UITableView,就像Twitter应用程序一样？或者任何参考,都可以

谢谢

Answer 1

您可以跟踪上次触摸日期并与当前触摸日期进行比较。如果差异足够小（0.7 秒），您可以将其视为双击。

UITabVarController在使用委托方法的子类中实现此功能shouldSelectViewController。

这是我正在使用的工作代码。

#import "TabBarController.h"
#import "TargetVC.h"

@interface TabBarController ()

@property(nonatomic,retain)NSDate *lastTouchDate;

@end

@implementation TabBarController

//Remeber to setup UINavigationController of each of the tabs so that its restorationIdentifier is not nil
//You can setup the restoration identifier in the IB in the identity inspector for you UIViewController or your UINavigationController
- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController{
    NSString *tab = viewController.restorationIdentifier;

    if([tab isEqualToString:@"TargetVC"]){

        if(self.lastTouchDate){

            UINavigationController *navigationVC = (UINavigationController*)viewController;
            TargetVC *targetVC = (TargetVC*)navigationVC.viewControllers[0];

            NSTimeInterval ti = [[NSDate date] timeIntervalSinceDate:self.lastTouchDate];
            if(ti < 0.7f)
               [targetVC scrollToTop];

        }

        self.lastTouchDate = [NSDate date];
    }

    return YES;
}