ios 卡顿，push多次同一个页面

场景：快速多次点击cell跳转到另一个页面，另一个页面被push多次。

原因：push后的页面有耗时操作或者刚好push到另一个页面时，另一个页面正好在reloadData卡住主线程。造成点击cell时卡住了。

解决方法：

重写导航控制器的push方法。

#import "DemoNavViewController.h"


@interface DemoNavViewController () 
// 记录push标志
@property (nonatomic, getter=isPushing) BOOL pushing;

@end


@implementation DemoNavViewController


- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.delegate = self;
}


- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if (self.pushing == YES) {
        NSLog(@"被拦截");
        return;
    } else {
        NSLog(@"push");
        self.pushing = YES;
    }
    
    [super pushViewController:viewController animated:animated];
}


#pragma mark - UINavigationControllerDelegate
-(void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    self.pushing = NO;
}


@end