Drawing UIImage into UITableViewCell in Monotouch

Question

So I'm giving MonoTouch a try, I want to fill a UITableView with custom objects, for the moment a simple rectangle. Here's the code where the table is drawn:

using System;
using System.Drawing;
using System.Collections.Generic;
using System.Linq;

using MonoTouch.Foundation;
using MonoTouch.UIKit;

namespace testProject

{
    [Register ("AppDelegate")]
    public partial class AppDelegate : UIApplicationDelegate
    {
        // class-level declarations
        UIWindow window;
        UITableView table;

    public override bool FinishedLaunching (UIApplication app, NSDictionary options)
    {
        // create a new window instance based on the screen size
        window = new UIWindow (UIScreen.MainScreen.Bounds);

        //make the window white
        var whiteColour = UIColor.FromRGB(255,255,255); 
        window.BackgroundColor = whiteColour;


        //create a UITableView
        table = new UITableView(window.Bounds);
        table.AutoresizingMask = UIViewAutoresizing.All;
        window.Add(table);

                    CellObject newCella = new CellObject();
            UIImage testImage = new UIImage();
            testImage = newCella.DrawCell(window);

            table.CellAt(0).ImageView.Image = testImage;

        // make the window visible
        window.MakeKeyAndVisible ();

        return true;
    }

}
}

And the class I'm testing with.

using System;
using System.Collections.Generic;
using System.IO;
using System.Drawing;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using MonoTouch.CoreGraphics;

namespace testProject
{
    public class CellObject : UIImage
    {
        //class level vars


            /* notes to self - this class will create an object which will be fed into a uitableview cell.
             * 
             * it will house everything needed for the object view, including gestures etc, it will have the following layers:
             * 1: background layer with social optins, vote, twitter, e-mail to friend etc
             * 2: object image layer with gestures
             * 3: object title layer with animation into view to show more when touched and held
             *
            */

        public UIImage DrawCell (UIWindow window) {
            //create a new graphics context
            int width = (int)Math.Ceiling(window.Bounds.Width);
            int height = (int)Math.Ceiling(window.Bounds.Height);
            CGBitmapContext ctx = new CGBitmapContext(IntPtr.Zero, width, height, 8, 4*width, CGColorSpace.CreateDeviceRGB(), CGImageAlphaInfo.PremultipliedFirst);

            //set up colours etc
            CGColor backgroundColour = new CGColor(1f, 0f, 0f, 1f);

            //draw a rectangle
            ctx.SetFillColor(backgroundColour);
            ctx.FillRect(new RectangleF(width / 2, height / 2, width / 2, height / 2));

            UIImage returnedImage = new UIImage();
            returnedImage = FromImage(ctx.ToImage());
            Console.WriteLine(returnedImage.Size.Width);

            return returnedImage;
        }
    }
}

I get no errors, everything runs, the table view shows but the CellObject class returned image is not put into the cell. I've tried putting it into a new view, same thing. Checking in the console shows the returned image is the expected width. Any ideas?

Thanks.

Answer 1

You need to be implementing UITableViewSource before any rows will display, example here. Settings the cells manually like you are doing won't work.

I recommend getting some simple text to be displayed before doing custom drawing. Just set cell.TextLabel.Text to something for starters.