在很多情况下，我们也时常有这样的需求，就是在UITabBar切换的时候，添加一些动画效果

 

1.在UITabBar触发点击方法的时候捕获当前点击的item

2.使用coreAnimation设置动画效果

 

- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item {    NSInteger index = [self.tabBar.items indexOfObject:item];    if (self.indexFlag != index) {        [self animationWithIndex:index];    }}// 动画- (void)animationWithIndex:(NSInteger) index {    NSMutableArray * tabbarbuttonArray = [NSMutableArray array];    for (UIView *tabBarButton in self.tabBar.subviews) {        if ([tabBarButton isKindOfClass:NSClassFromString(@"UITabBarButton")]) {            [tabbarbuttonArray addObject:tabBarButton];        }    }    CABasicAnimation*pulse = [CABasicAnimation animationWithKeyPath:@"transform.scale"];    pulse.timingFunction= [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];    pulse.duration = 0.08;    pulse.repeatCount= 1;    pulse.autoreverses= YES;    pulse.fromValue= [NSNumber numberWithFloat:0.7];    pulse.toValue= [NSNumber numberWithFloat:1.3];    [[tabbarbuttonArray[index] layer]     addAnimation:pulse forKey:nil];    self.indexFlag = index;}