Vas-Stickan simple Xamarin App

Jun 08

Xmarin Crossplattform slider

I have started to write a crossplattform app with Xamarin for ios, windows and Android devices. I started using Xamarin a year ago. But did not get anywhere. I restarted now and decided to make a Hello world applikation in the form of a slider.

This slider can be used to give a level of much pain you have. IRL they are used by nurses and doctors when asking patients: Show us on this stick how much pain you have on a scale between 0 and 10.
Screenshot of iPad emulator on Mac
Screenshot_iPad_sim_VAS_ 2014-06-08 _ 18.24.27




Code is here:

https://github.com/patriklindstrom/VAS-Stickan

Ill add more blogpost as I evovole. My goal is to make and publish a simple app on all three plattform with unit test and shared code. Also share problems with publishing them on all three app stores.
The important code is in the ViewController I decided to declare all GUI in code instead of xml or XAML. I wanted control over it and I did not get the XCode GUI drag and drop to work.

 public class MyViewController : UIViewController
    {
         UISlider _sliderVas;
        private const float SLIDER_WIDTH = 630;
        private const float SLIDER_HEIGHT = 50;
        UILabel _lblValue;
        private const float LBL_VALUE_OFFSET = 300;
        private const float LBL_VALUE_WIDTH = 50;
        private const float LBL_VALUE_HEIGHT = 50;
        UILabel _lblHeader;
        private const float LBL_HEADER_OFFSET = -300;
        private const float LBL_HEADER_WIDTH = 200;
        private const float LBL_HEADER_HEIGHT = 50;
 
        public MyViewController()
        {
        }
 
        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
 
            View.Frame = UIScreen.MainScreen.Bounds;
            View.BackgroundColor = UIColor.White;
            View.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight;
            //label
 
            _lblHeader = new UILabel(componentRect(View.Frame, LBL_HEADER_WIDTH, LBL_HEADER_HEIGHT, LBL_HEADER_OFFSET)){
                Text = "VAS - Stickan",
                AutoresizingMask = UIViewAutoresizing.FlexibleWidth 
               | UIViewAutoresizing.FlexibleTopMargin 
               | UIViewAutoresizing.FlexibleBottomMargin,
                Font = UIFont.FromName("Helvetica-Bold", 40f),
                AdjustsFontSizeToFitWidth = true, // gets smaller if it doesn't fit
                LineBreakMode = UILineBreakMode.TailTruncation,
                Lines = 1, // 0 means unlimited
            };
            View.Add(_lblHeader);
            // slider
            _sliderVas = new UISlider(componentRect(View.Frame, SLIDER_WIDTH, SLIDER_HEIGHT, 0))
            {
                AutoresizingMask = UIViewAutoresizing.FlexibleWidth ,
                MinimumTrackTintColor = UIColor.Green,
                MaximumTrackTintColor = UIColor.Red,
                MinValue = 0f,
                MaxValue = 10f,
                Value = 2.5f
            };
            View.Add(_sliderVas);
            _sliderVas.ValueChanged += OnSliderValueChanged;
            //label
            _lblValue = new UILabel(componentRect(View.Frame, LBL_VALUE_WIDTH, LBL_VALUE_HEIGHT, LBL_VALUE_OFFSET)){
                Text = "Your Pain",
                AutoresizingMask = UIViewAutoresizing.FlexibleWidth ,
                Font = UIFont.FromName("Helvetica-Bold", 40f),
                AdjustsFontSizeToFitWidth = true, // gets smaller if it doesn't fit
                LineBreakMode = UILineBreakMode.TailTruncation,
                Lines = 1, // 0 means unlimited
            };
            View.Add(_lblValue);
 
        }
 
        private RectangleF componentRect(RectangleF viewFrame,float width,float height,float vOffset)
        {
            return new RectangleF(viewFrame.Width / 2 - width / 2
                , viewFrame.Height / 2 - height / 2 + vOffset
                , width, height);
        }
 
        private void OnSliderValueChanged(object sender, EventArgs e)
        {
            // display the value in a label
            Debug.Assert(sender.GetType() == typeof(UISlider), "A UISlider should be the caller of this delegate");
            UISlider mySlider = (UISlider)sender;
 
            _lblValue.Text = mySlider.Value.ToString("0.0");
        }    
    }

I will write new blogpost as I progress

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