Question

我在Viewcontroller A上有一本字典。我在viewcontroller上传递它B.On ViewController它在viewcontroller字典上显示数据B.But，在Viewcontroller中它不显示任何数据吗？

ViewController A：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    TableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];

    if (cell== nil) {

        cell = [[TableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"Cell"];
    }
    if(_List.count>0) {

        [cell setupCell:[_List objectAtIndex:indexPath.row]];
        ViewControllerB *vc=[[ViewController alloc]init];
        vc.userIdInfo=[_List objectAtIndex:indexPath.row];
    }
    return cell;
}

ViewController B：

- (void)viewDidLoad {
    [super viewDidLoad];

    NSLog(@"_userIdInfo %@",userIdInfo);
    if([userIdInfo valueForKey:@"UserID"]) {
        [self fetchDataFromServer:getdetail];
    }
}

此NSLog(@"_userIdInfo %@",userIdInfo)打印null。而vc.userIdInfo打印字典

{
    Count = 3;
    UserID = "6gdab241-j176-1121-lde2-as8d21f62231";
    UserName = "abc@gmail.com";
}

Answer 1

您需要在DID选择方法中执行ViewController B初始化，如下所示。

不要在cellForRowAtIndexPath初始化它。

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

    // 1st Type
    ViewControllerB *vc=[[ViewController alloc]init];
    vc.userIdInfo=[_List objectAtIndex:indexPath.row];
    [self.navigartionController pushViewController:aVC animated:YES];

    //2nd Type
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    ViewControllerB *aVC = [storyboard instantiateViewControllerWithIdentifier:@"ViewController"];
    aVC.userInfo = <set your data>;
    [self.navigartionController pushViewController:aVC animated:YES];

}

希望这会有所帮助。

Answer 2

代码

 ViewControllerB *vc=[[ViewController alloc]init];
 vc.userIdInfo=[_List objectAtIndex:indexPath.row];

只创建ViewController;它没有在任何地方呈现它。此外，实例 vc 将在您离开

范围后立即解除分配

if(_List.count>0){}

你的方法

- (void)viewDidLoad {
    [super viewDidLoad];

    NSLog(@"_userIdInfo %@",userIdInfo);
    if([userIdInfo valueForKey:@"UserID"])
    {
        [self fetchDataFromServer:getdetail];
    }
}

永远不会调用

，因为您的视图永远不会加载。

我认为，您真正想要的是使用navigationController实例或当前viewController来呈现您的vc实例

[self.navigationController presentViewController: vc animated: YES completion: nil];

Answer 3

在目标C中， cellForRowAtIndexPath 方法用于显示数据。根据代码，您在 cellForRowAtIndexPath 中对ViewController B进行了调整。它将多次分配ViewController B，从而导致内存消耗。

我建议你在ViewController A的ViewDidLoad中初始化。

要将数据从A传递到B，您需要使用UITableViewDelegate的 didSelectRowAtIndexPath 方法。

示例：

ViewController A：

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

   // 1st Type
   ViewControllerB *vc=[[ViewController alloc]init];
   vc.userIdInfo=[_List objectAtIndex:indexPath.row];
   [self.navigartionController pushViewController:aVC animated:YES];

}

}

ViweController B

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;

    using Android.App;
    using Android.Content;
    using Android.OS;
    using Android.Runtime;
    using Android.Views;
    using Android.Widget;

    namespace SocrateMobile.Droid.Adapter
    {
    class PulledItemList_Adapter : BaseAdapter<oneimg_twolbl>
    {
        private Activity context;
        private List<oneimg_twolbl> AllItemList;


        public PulledItemList_Adapter(Activity context, List<oneimg_twolbl>      AllItemList)
        {
            this.AllItemList = AllItemList;
            this.context = context;
        }
        public oneimg_twolbl GetItem_bypos(int position)
        {
            return AllItemList[position];
        }
        public override oneimg_twolbl this[int position]
        {
            get { return AllItemList[position]; }
        }

        public override int Count
        {
            get { return AllItemList.Count; }
        }

        public override long GetItemId(int position)
        {
            return position;
        }

        public override View GetView(int position, View convertView, ViewGroup parent)
        {
            Holder_oneimg_twolbl holder = null;
            var view = convertView;

            if (view != null)
                holder = view.Tag as Holder_oneimg_twolbl;


            if (holder == null)
            {
                holder = new Holder_oneimg_twolbl();
                view = context.LayoutInflater.Inflate(Resource.Layout.oneimg_twolbl, null);
                holder.Text = view.FindViewById<TextView>(Resource.Id.text_list4_view);
                holder.Text2 = view.FindViewById<TextView>(Resource.Id.text_list4_view2);
                holder.Image = view.FindViewById<ImageButton>(Resource.Id.image_list4_view);
                view.Tag = holder;
            }

            var current_item = AllItemList[position];


            holder.Text.Text = current_item.FirstTxt;
            holder.Text2.Text = current_item.SecondTxt;
            holder.Image.SetImageResource(current_item.FirstImg);
            holder.Image.Click += (sender, e) =>
            {
               int x = position;
            };
            return view;
        }



        public class Holder_oneimg_twolbl : Java.Lang.Object
        {
            public TextView Text { get; set; }
            public TextView Text2 { get; set; }
            public ImageButton Image { get; set; }
        }
    }
}

通过属性

3 个答案: