以编程方式调用push segue和prepareforsegue方法

问题描述

我正在以编程方式调用 push segue ，如下所示

I'm invoking push segue programatically as below

    UIStoryboard *mainStoryBoard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    UIViewController *vc = [mainStoryBoard instantiateViewControllerWithIdentifier:@"addToCartViewContollerForItem"];
    [self.navigationController pushViewController: vc animated:YES];

但我的问题是我想将这个segue的一些信息发送到目标viewcontroller。但方法 - （void）prepareForSegue：（UIStoryboardSegue *）segue发送者：（id）发件人根本没有被解雇。

but my problem is I want to send some info with this segue to the destination viewcontroller. But the method - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender is not getting fired at all.

这就是prepareforsegue方法

this is how the prepareforsegue method

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
    NSLog(@"segue from deals screen");
    //addToCartViewContollerForItem
    if([[segue identifier] isEqualToString:@"addToCartSegue"]){
        NSIndexPath *selectedRow = [[self tableView] indexPathForSelectedRow];

        Item *currentItem = [[Item alloc]init];
        currentItem = [itemList objectAtIndex:[selectedRow row]];

        RESTAddToCartViewController *vc = [segue destinationViewController];
        [vc setCurrentItem:currentItem];
    }

}

我在这里缺少什么？

推荐答案

从 didSelectRowAtIndexPath调用 performSegueWithIdentifier ： 方法

Call performSegueWithIdentifier: from your didSelectRowAtIndexPath method

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [self performSegueWithIdentifier:@"addToCartSegue" sender:self];
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
    NSLog(@"segue from deals screen");
    //addToCartViewContollerForItem
    if([[segue identifier] isEqualToString:@"addToCartSegue"]){
        NSIndexPath *selectedRow = [[self tableView] indexPathForSelectedRow];

        Item *currentItem = [[Item alloc]init];
        currentItem = [itemList objectAtIndex:[selectedRow row]];

        RESTAddToCartViewController *vc = [segue destinationViewController];
        [vc setCurrentItem:currentItem];
    }

}

在Swift 2.3中

//MARK: didSelectRowAtIndexPath

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    performSegueWithIdentifier("addToCartSegue", sender: self)
}


// MARK: - Navigation

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    if segue.identifier == "addToCartSegue" {
        let selectedIndexPath = self.tableView.indexPathForSelectedRow
        let currentItem: Item = itemList[selectedIndexPath.row]
        if let viewcontroller = segue.destinationViewController as? RESTAddToCartViewController {
            viewcontroller.currentItem = currentItem
        }
    }
}

Swift 3

//MARK: didSelectRowAtIndexPath

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    performSegue(withIdentifier: "addToCartSegue", sender: self)
}

// MARK: - Navigation

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "addToCartSegue" {
        if let selectedIndexPath = self.tableView.indexPathForSelectedRow {
            let currentItem: Item = itemList[selectedIndexPath.row]
            if let viewcontroller = segue.destination as? RESTAddToCartViewController {
                viewcontroller.currentItem = currentItem
            }
        }
    }
}

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