I'm creating a Xamarin app for iOS and I've added a UITableViewCell to a storyboard to give it my own style. I did add a class to this custom UITableViewCell, namely MainMenuCell. I added two labels to the cell and connected them with the MainMenuCell.h file, resulting in the following code:
MainMenuCell.cs
using System;
using Foundation;
using UIKit;
namespace MyProjectNamespace
{
public partial class MainMenuCell : UITableViewCell
{
public MainMenuCell (IntPtr handle) : base (handle)
{
}
public MainMenuCell () : base ()
{
}
public void SetCellData()
{
projectNameLabel.Text = "Project name";
projectDateLabel.Text = "Project date";
}
}
}
MainMenuCell.h (auto-generated):
using Foundation;
using System.CodeDom.Compiler;
namespace MyProjectNamespace
{
[Register ("MainMenuCell")]
partial class MainMenuCell
{
[Outlet]
UIKit.UILabel projectDateLabel { get; set; }
[Outlet]
UIKit.UILabel projectNameLabel { get; set; }
void ReleaseDesignerOutlets ()
{
if (projectNameLabel != null) {
projectNameLabel.Dispose ();
projectNameLabel = null;
}
if (projectDateLabel != null) {
projectDateLabel.Dispose ();
projectDateLabel = null;
}
}
}
}
Now I have my UITableViewSource here, and I'm trying to initialize the MainMenuCell from the GetCell method:
using System;
using UIKit;
using Foundation;
namespace MyProjectNamespace
{
public class MainMenuSource : UITableViewSource
{
public MainMenuSource ()
{
}
public override nint NumberOfSections (UITableView tableView)
{
return 1;
}
public override string TitleForHeader (UITableView tableView, nint section)
{
return "Projects";
}
public override nint RowsInSection (UITableView tableview, nint section)
{
return 1;
}
public override UITableViewCell GetCell (UITableView tableView, NSIndexPath indexPath)
{
MainMenuCell cell = new MainMenuCell();
cell.SetCellData ();
return cell;
}
}
}
However, it keeps throwing me a System.NullReferenceException at the line:
projectNameLabel.Text = "Project name";
It says: object reference not set to an instance of an object.
What am I missing here? Any help would be highly appreciated.
You're almost there – instead of creating a new cell by yourself, let iOS do the work and dequeue the result.
public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
{
var cell = (MainMenuCell)tableView.DequeueReusableCell("MainMenuCell");
cell.SetCellData();
return cell;
}
Note, that "MainMenuCell" is a identifier for the dynamic prototype cell from the Storyboard, you can name it whatever you want, but it has to be the same withing Storyboard and your Datasource.
Related
I need the UIMenuItem to call a method inside the UITableViewCell. Something similar is possible in swift as explained here: https://stackoverflow.com/a/31358474/202179 .
At the moment I am only able to call the method inside the UIViewController from the UIMenuItem if I add an Export attribute to the method.
There is some trick in the export of this method in the cell, but I have failed to find it till now. I would expect this code to work, but it doesn't:
[Register("CustomCell")]
public class CustomCell : UITableViewCell
{
public CustomCell(IntPtr intPtr) : base(intPtr)
{
var menuItem = new UIMenuItem("Menu Item", new ObjCRuntime.Selector("CustomCell.SeekSelectedText"));
UIMenuController.SharedMenuController.MenuItems = new UIMenuItem[] { menuItem };
UIMenuController.SharedMenuController.Update();
}
[Export("SeekSelectedText")]
void SeekSelectedText()
{
//do something
}
}
As said just quoting a different selector inside the UIViewController works, so the problem is that this selector doesn't appear to be recognized whatever I try.
Here is my test and the custom UIMenuItem works fine.
First, define a custom cell class which inherits UITableViewCell
class MyCell: UITableViewCell
{
public MyCell(UITableViewCellStyle style, string reuseIdentifier):base(style, reuseIdentifier)
{
}
[Export("custom")]
void Custom()
{
//do something
Console.WriteLine("custom pop up");
}
public override bool CanPerform(Selector action, NSObject withSender)
{
if (action == new Selector("custom"))
return true;
else
return false;
}
}
Second, set the source of your UITableView
class MyTableViewSource : UITableViewSource
{
int i = 0;
// create custom cell
public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
{
string cellStr = "cell";
MyCell cell = (MyCell)tableView.DequeueReusableCell(cellStr);
if (cell == null)
{
cell = new MyCell(UITableViewCellStyle.Subtitle, cellStr);
cell.TextLabel.Text = $"User Name {i}";
cell.DetailTextLabel.Text = $"details here... {i++}";
}
return cell;
}
public override nint RowsInSection(UITableView tableview, nint section)
{
return 10;
}
}
Then override the realted methods(e.g., ShouldShowMenu, CanPerformAction).
class MyTableViewDelegate : UITableViewDelegate
{
public override bool ShouldShowMenu(UITableView tableView, NSIndexPath rowAtindexPath)
{
return true;
}
public override bool CanPerformAction(UITableView tableView, Selector action, NSIndexPath indexPath, NSObject sender)
{
return true;
}
public override void PerformAction(UITableView tableView, Selector action, NSIndexPath indexPath, NSObject sender)
{
}
public override bool ShouldHighlightRow(UITableView tableView, NSIndexPath rowIndexPath)
{
return true;
}
}
Last, don't foget to add custom MenuItem to your UITableViewCell.
UIMenuController.SharedMenuController.MenuItems = new UIMenuItem[] {
new UIMenuItem ("Custom", new Selector ("custom"))
};
Since UICollectionView has similar functions to UITableVIew, you can directly refer to the sample SimpleCollectionView.
We've created a TableViewController so that a user can enable/disable different notification types. After the initial load, everything is fine until the user scrolls to the bottom then back to the top and the first 1-2 table view cells aren't displaying correctly.
Example:
https://imgur.com/7n2VpTo
Typically deleting and recreating the view controller and xib/cs files fixes this, but was wondering if any one knows the cause of this.
Controller Code:
public override nfloat GetHeightForRow(UITableView tableView, NSIndexPath indexPath)
{
return 305;
}
public override nint NumberOfSections(UITableView tableView)
{
return 1;
}
public override nint RowsInSection(UITableView tableView, nint section)
{
return _numRows;
}
public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
{
var cell = tableView.DequeueReusableCell(Setting.Key) as Setting;
if (cell == null)
{
var values = _settings.Where(s => s.Index == indexPath.Row).FirstOrDefault();
cell = new Setting(values);
var views = NSBundle.MainBundle.LoadNib(Setting.Key, cell, null);
cell = Runtime.GetNSObject(views.ValueAt(0)) as Setting;
}
cell.SelectionStyle = UITableViewCellSelectionStyle.None;
cell?.PopulateData(_settings.Where(s => s.Index == indexPath.Row).FirstOrDefault(), this);
return cell;
}
public override void ViewWillLayoutSubviews()
{
base.ViewWillLayoutSubviews();
}
Cell Code:
public partial class Setting : UITableViewCell
{
public static readonly NSString Key = new NSString("Setting");
public static readonly UINib Nib;
public SettingModel Values { get; set; }
static Setting()
{
Nib = UINib.FromName("Setting", NSBundle.MainBundle);
}
protected Setting(IntPtr handle) : base(handle) { }
public Setting() : base() {
}
public override void LayoutSubviews()
{
base.LayoutSubviews();
}
public void PopulateData(SettingModel values)
{
//logic...
}
}
Upgrading to Visual Studio for Mac 8.6.5 resolved the issue.
I'm faced with a problem with my iOS Xamarin App.
Whenever I try to add a tableView in one of my views with the Storyboard, and I launch my app I have always the same error.
Foundation.MonoTouchException: Objective-C exception thrown. Name:
NSInvalidArgumentException Reason: -[TableSource initWithCoder:]:
unrecognized selector sent to instance 0x17d6a620
Here is my TableSource code:
using Foundation;
using System;
using UIKit;
namespace SmartTransportNatif.iOS2
{
public partial class TableSource : UITableViewSource
{
protected string[] tableItems;
protected string cellIdentifier = "TableCell";
HomeTableController home;
public TableSource (IntPtr handle) : base (handle)
{
}
public TableSource (string[] items, HomeTableController home)
{
this.home = home;
}
public override nint RowsInSection(UITableView tableview, nint section)
{
return tableItems.Length;
}
/// <summary>
/// Called when a row is touched
/// </summary>
public override void RowSelected(UITableView tableView, NSIndexPath indexPath)
{
UIAlertController okAlertController = UIAlertController.Create("Row Selected", tableItems[indexPath.Row], UIAlertControllerStyle.Alert);
okAlertController.AddAction(UIAlertAction.Create("OK", UIAlertActionStyle.Default, null));
home.PresentViewController(okAlertController, true, null);
tableView.DeselectRow(indexPath, true);
}
/// <summary>
/// Called by the TableView to get the actual UITableViewCell to render for the particular row
/// </summary>
public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
{
// request a recycled cell to save memory
UITableViewCell cell = tableView.DequeueReusableCell(cellIdentifier);
// if there are no cells to reuse, create a new one
if (cell == null)
cell = new UITableViewCell(UITableViewCellStyle.Default, cellIdentifier);
cell.TextLabel.Text = tableItems[indexPath.Row];
return cell;
}
}
}
Here is my storyboard:
Here are the properties of my Tableview in the HomeTableController:
Does someone know what is missing or wrong?
I have two UITableView in the same UIViewController.
tblView1 & tblView2.
Both TableViews are bringing data dynamically.
Now my problem is: I want to load data in tblView2 on the basis of SelectedRow from tblView1.
For Example, when I select a company name from tblView1, then tblView2 needs to populate the Cars made by that company.
I have rowIndex of my first table (tblView1), but i can't bind my tblView2 from the RowSelected Method of tblView1.
I need help in binding my tblView2. How can i do this?
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Xml.Serialization;
using CoreGraphics;
using Foundation;
using UIKit;
namespace Tables
{
public partial class ViewController : UIViewController
{
protected ViewController(IntPtr handle) : base(handle)
{
// Note: this .ctor should not contain any initialization logic.
}
public ViewController()
{
//tblView2.Source = new CompanyModelsSource();
// Note: this .ctor should not contain any initialization logic.
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
if (tblView1 != null)
{
tblView1.Source = new CarModelsSource();
}
// Perform any additional setup after loading the view, typically from a nib.
}
public override void DidReceiveMemoryWarning()
{
base.DidReceiveMemoryWarning();
// Release any cached data, images, etc that aren't in use.
}
}
class CompanyModelsSource : UITableViewSource
{
private List<Companies> _Companies;
NSString _cellID = new NSString("TableCell");
public CompanyModelsSource()
{
_Companies = CompanyTableSource.AllCompany();
}
public override nint RowsInSection(UITableView tableview, nint section)
{
// tell the TableView how many rows to create
return _Companies.Count;
}
public override void RowSelected(UITableView tableView, NSIndexPath indexPath)
{
//I can't access my tblView2 in this method. So where i can bind my other UITableView?
UILabel lblTotalFacilities = new UILabel();
lblTotalFacilities.Layer.BackgroundColor = UIColor.Blue.CGColor;
lblTotalFacilities.Frame = new CGRect(305, 200, 1024, 400);
ViewController vc = new ViewController();
vc.View.AddSubview(lblTotalFacilities);
}
public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
{
Company currentCompany = _Companies[indexPath.Row];
var cell = tableView.DequeueReusableCell(_cellID) as CompanyTableCell;
if (cell == null) { cell = new CompanyTableCell(_cellID); }
cell.UpdateCellControlsWithAuditData(currentCompany.Name);
return cell;
}
}
public class CompanyTableSource
{
public CompanyTableSource()
{
}
public static List<Companies> AllCompany()
{
CompanyCollection CC = null;
string path1 = path + "Companies.xml";
XmlSerializer serializer = new XmlSerializer(typeof(CompanyCollection));
StreamReader reader = new StreamReader(path1);
CC = (CompanyCollection)serializer.Deserialize(reader);
reader.Close();
List<Companies> comp = CC.CompanyCollection.Cast<Companies>().ToList();
return comp;
}
}
public class CompanyTableCell : UITableViewCell
{
UILabel nameLabel;
public CompanyTableCell(NSString cellId) : base(UITableViewCellStyle.Default, cellId)
{
SelectionStyle = UITableViewCellSelectionStyle.Gray;
ContentView.BackgroundColor = UIColor.FromRGB(54, 194, 36);
var newFont = UIFont.SystemFontOfSize(12);
nameLabel = new UILabel();
nameLabel.Font = newFont;
ContentView.AddSubviews(new UIView[] { nameLabel });
}
public void UpdateCellControlsWithAuditData(string Name)
{
nameLabel.Text = Name;
}
public override void LayoutSubviews()
{
base.LayoutSubviews();
nameLabel.Frame = new CGRect(10, 0, 350, 33);
}
}
}
Hope this helps. Created everything in a single file for simplicity.
public partial class ViewController : UIViewController
{
public ViewController() : base("ViewController", null)
{
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
// Perform any additional setup after loading the view, typically from a nib.
var companySource = new CompanyTableSource();
tblView1.Source = companySource;
companySource.ItemSelected += OnCompanyItemSelected;
}
//this will handle the ItemSelected event
//here you will retrieve the data for the second UITableView
void OnCompanyItemSelected(object sender, Company e)
{
//you can do it this way
tblView2.Source = new CarTableSource(e.Id);
List<Car> cars = GetCarsByCompanyId(e.Id);
//or this whay
tblView2.Source = new CarTableSource(cars);
}
List<Car> GetCarsByCompanyId(int id)
{
//Your logic to get the data goes here
throw new NotImplementedException();
}
}
public class CompanyTableSource : UITableViewSource
{
// You can use the whole object or just an integer (companyId)
public event EventHandler<Company> ItemSelected;
public IList<Company> Items { get; private set; } = new List<Company>();
public override void RowSelected(UITableView tableView, NSIndexPath indexPath)
{
var item = Items[indexPath.Row];
ItemSelected?.Invoke(this, item);
}
public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
{
//Do your implementation
throw new NotImplementedException();
}
public override nint RowsInSection(UITableView tableview, nint section)
{
return Items.Count;
}
}
public class CarTableSource : UITableViewSource
{
public IList<Car> Items { get; private set; } = new List<Car>();
public CarTableSource(int companyId)
{
//Get your data based on the companyId
}
//Or pass in the data already retreived. (I preffer this method)
public CarTableSource(IList<Car> cars)
{
Items = cars;
}
public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
{
//Do your implementation
throw new NotImplementedException();
}
public override nint RowsInSection(UITableView tableview, nint section)
{
return Items.Count;
}
}
I'm trying to change the View Controller when someone Taps on a Table View Cell. However Im not doing it the conventional way. I am submethoding the method that actually detects the tap so I could use it from any other class. Here is how I am doing it:
TableSource.cs
public override void RowSelected (UITableView tableView, NSIndexPath indexPath)
{
if (OnRowSelected != null) {
OnRowSelected (this, new RowSelectedEventArgs (tableView, indexPath));
}
}
public class RowSelectedEventArgs : EventArgs
{
public UITableView tableView { get; set; }
public NSIndexPath indexPath { get; set; }
public RowSelectedEventArgs(UITableView tableView, NSIndexPath indexPath) : base()
{
this.tableView = tableView;
this.indexPath = indexPath;
}
}
public event EventHandler<RowSelectedEventArgs> OnRowSelected;
Request.cs
tableSourceTable.OnRowSelected += (object sender, TableSource<Datum>.RowSelectedEventArgs e) => {
vc = new InstagramModalController (){instaData = tableSourceTable.instaData[e.indexPath.Row]};
this.navControl.PushViewController(this.vc,true);
this.getMediaID(tableSourceTable.instaData[e.indexPath.Row].link);
new UIAlertView(tableSourceTable.instaData[e.indexPath.Row].user.full_name.ToString(),
tableSourceTable.instaData[e.indexPath.Row].caption.text.ToString(), null, "OK", null).Show();
e.tableView.DeselectRow (e.indexPath, true);
};
That is all the code from the TableSource class and I would be okay with any change.