ios - 以编程方式创建按钮以转到下一个 View 时如何在 View 中传递数据？

Question

我在 ViewController 中以编程方式创建了一个按钮。当用户点击这个按钮时，它会转到一个名为 SecondViewController 的新 View Controller 。在 Storyboard 中使用 segues，我知道如何在 View Controller 之间传递数据，并且在过去已经做到了。

我的问题:如果我不使用 Storyboard 并以编程方式执行此操作，我该怎么做？

SecondViewController 有一个名为 data 的 NSString 属性。

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


    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [button addTarget:self action:@selector(aMethod:) forControlEvents:UIControlEventTouchDown];
    [button setTitle:@"Show View" forState:UIControlStateNormal];
    button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
    [self.view addSubview:button];

}

- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{

    //load the street view container
    if ([[segue identifier] isEqualToString:@"firstToSecond"]) {

        //send coordinates to container
        SecondViewController *embed = segue.destinationViewController;
        embed.data = @"test";

    }

}

- (void)aMethod:(UIButton*)button
{
    NSLog(@"Button  clicked.");

    UIViewController *myController = [self.storyboard instantiateViewControllerWithIdentifier:@"SecondViewController"];
    [self.navigationController pushViewController: myController animated:YES];

    //I get an error on these 2 lines of code within Xcode.
    MyCustomSegue *segue = [[MyCustomSegue alloc] initWithIdentifier:@"firstToSecond" source:self destination:SecondViewController];
    [self prepareForSegue:segue sender:sender];
    [segue perform];

}

在 xcode 中，我在这 2 行中收到错误:

    MyCustomSegue *segue = [[MyCustomSegue alloc] initWithIdentifier:@"firstToSecond" source:self destination:SecondViewController];
    [self prepareForSegue:segue sender:sender];

有什么建议吗？

Answer 1

如果您想使用 [self.navigationController pushViewController:myController animated:YES] 将 viewController 添加到层次结构中您不需要以编程方式创建 segue。
prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender在destinationViewController 被推送之前调用，让您有机会在它出现在屏幕上之前修改或传递数据给它。所以不要手动调用这个函数。您需要做的就是将您的代码从那里移动到两者之间

UIViewController *myController = [self.storyboard instantiateViewControllerWithIdentifier:@"SecondViewController"];
myController.data = @"test";
[self.navigationController pushViewController: myController animated:YES];