ios在segue期间将值传递给另一个视图

Question

试着做一些我见过很多地方记录的事情,但似乎无法管理.我想在segue期间将数据从一个视图传递到另一个视图.

这是源视图中的prepareForSegue方法:

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

    //pass values
DetailViewController *dest = (DetailViewController *)[segue destinationViewController];

dest.locTitle = [value valueForKeyPath:@"title"];
dest.locInfo = [value valueForKeyPath:@"info"];



// NSLog(@"The title is: %@, and the info is: %@.",dest.locTitle,dest.locInfo);

}

如果我最后启用NSLog,我会看到正确的值...

这是目标视图上的接口:

#import <UIKit/UIKit.h>

@interface DetailViewController : UIViewController{

}

@property (strong, nonatomic) NSString *locTitle;
@property (strong, nonatomic) NSString *locInfo;
@property (weak, nonatomic) IBOutlet UILabel *detailMainText;
@property (weak, nonatomic) IBOutlet UILabel *detailTitle;

@end

...这里是目标视图上的viewDidLoad和相关的@synthesize:

@synthesize detailMainText,detailTitle,locTitle,locInfo;

- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(@"In viewDidLoad - the title is: %@ and the info is: %@",self.locTitle,self.locInfo);
detailTitle.text = locTitle;
detailMainText.text = locInfo;
}

这NSLog报告null为每个变量的值.

我很感激你能给我的任何帮助.我确定我做的事情很愚蠢,很明显.

在此先感谢您的帮助.

---

很久以后...

---

好的......我想我正在缩小范围.

我发现了(违反直觉)

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

被叫之后

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

这让人感到困惑,并且还在我的小方案中找出了NSDictionary我的详细信息视图中应该显示的数据源块.目前我这样做:

// send info to detail view according to which row selected
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    //Get the selected object in order to fill out the detail view
    myValue = [myLocations objectForKey:[locationsIndex objectAtIndex:indexPath.row]];

}

但是因为这发生在 segue之后,它有点无用.如何访问prepareForSegue方法中的行号？

再次感谢.

---

......最后......

---

这是问题的答案:

如何在prepareForSegue方法中访问选定的行号？

希望有人会发现它很有用.

首先,IBOutlet在listView控制器的界面中为tableview 设置一个:

@property (weak, nonatomic) IBOutlet UITableView *tableView;

然后你的prepareForSegue可以做到这一点:

- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString: @"showDetail"]) {
    //pass values
    NSLog(@"The sender is %@",sender);

    NSIndexPath *indexPath = [self.tableView indexPathForCell:sender];
    //Get the selected object in order to fill out the detail view
    id myValue = [myLocations objectForKey:[locationsIndex objectAtIndex:indexPath.row]];

    DetailViewController *dest = [segue destinationViewController];
    dest.locTitle = [myValue valueForKeyPath:@"title"];
    dest.locInfo = [myValue valueForKeyPath:@"info"];

    //NSLog(@"The title is: %@, and the info is: %@.",dest.locTitle,dest.locInfo);
}
}

Answer 1

您可以通过以下方式实现:首先将要发送的值传递到目标控制器:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
     [self performSegueWithIdentifier:@"segueToLocation" sender:the object you want to pass];
}

然后在这里得到对象

- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString: @"segueToLocation"]) {    
         DetailViewController *dest = (DetailViewController *)[segue destinationViewController];
         //the sender is what you pass into the previous method
         dest.target=sender
    }
}

Answer 2

您不需要创建目标视图控制器的本地实例变量。这将执行相同的操作：

[segue.destinationViewController setLocTitle: [myValue valueForKeyPath:@"title"];
[segue.destinationViewController setLocInfo: [myValue valueForKeyPath:@"info"];