Question

我有一个新的viewController按钮。当我按下按钮时，在新的视图控制器出现之前有一个可见的3-4秒延迟。我已经阅读了有关stackoverflow的其他问题，通常问题在于destinationViewController或sourceViewController上的代码（尚未完成）。在我的情况下，如果我在destinationViewController上的viewDidLoad上设置断点，则甚至在代码执行之前就会发生延迟。

另外，我的代码不会做任何超过一毫秒的事情。

这是我的destinationViewController的代码。我在prepareForSegue中没有任何内容......方法fyi。

如何摆脱这种延迟？谢谢！

如果你需要别的东西来诊断，请随意询问，谢谢。

#import "ViewSettingsViewController.h"

@interface ViewSettingsViewController ()

@end

@implementation ViewSettingsViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    if ([HelperMethods getUserPreference:@"notificationTime"]==nil) {
        NSDate * now = [[NSDate alloc] init];
        NSCalendar *cal = [NSCalendar currentCalendar];
        NSDateComponents * comps = [cal components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:now];
        [comps setHour:19];
        [comps setMinute:0];
        [comps setSecond:0];
        NSDate * date = [cal dateFromComponents:comps];
        [self.timePicker setDate:date animated:TRUE];
    } else {
        [self.timePicker setDate:[HelperMethods getUserPreference:@"notificationTime"]];
    }
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

-(void) viewWillDisappear:(BOOL)animated {
    if ([self.navigationController.viewControllers indexOfObject:self]==NSNotFound) {
        // back button was pressed.  We know this is true because self is no longer
        // in the navigation stack.
        [HelperMethods setUserPreference:self.timePicker.date forKey:@"notificationTime"];

    }
    [super viewWillDisappear:animated];
}

@end

Answer 1

你有以下代码：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

我确实有[self.tableView deselectRowAtIndexPath:indexPath animated:YES];

我尝试在dispatch_get_main_query中添加它，现在它再次顺利。

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    dispatch_async(dispatch_get_main_queue(), ^{
        [self.tableView deselectRowAtIndexPath:indexPath animated:YES];
    });
}

Answer 2

想出来。结果是这一行的滞后时间：

[super viewDidLoad]

是从destinationViewController viewDidLoad方法调用的。那是重新加载每次启动segue的视图，这是一个沉重的方法。我评论说排除了问题并解决了这个问题。不知道为什么我每次都想重新加载超级视图...

iOS segue很慢 - 即使没有对destinationViewController进行任何处理

2 个答案: