Set Spinner-Item Backgroundcolor with SpannableString

Question

I am using SpannableStrings to set different background colors for the items in my Spinner.

var spinnerList = new List<SpannableString>();
foreach(var mySpinnerItem in spinnerItems)
{
    var tmpSpannable = new SpannableString(mySpinnerItem.Text);
    tmpSpannable.SetSpan(new BackgroundColorSpan(mySpinnerItem.Color), 0, mySpinnerItem.Text.Length, 0);
    spinnerList.Add(tmpSpannable);
}

var spinnerAdapter = new ArrayAdapter<SpannableString>(Context, Android.Resource.Layout.SimpleSpinnerItem, spinnerList);
spinner.Adapter = spinnerAdapter;

The result looks like this:

I would like to have all items in the same width.

Two possible results for which I find no solution:

• setting the width of all items to the width of the widest item
• setting the width of all items to the width of the whole Spinner

How can i fix this problem or what is an alternative approach to set programmatically different background colors to the spinner item?

---

This is how Result 1 should look like:

Please ignore that the font color of the first element is not set in contrast to the background

Answer 1

According to your code above, it just adds a background color to your textview, not the entire item,you could custom your adapter,then set the color to the itemview,here is a sample which pass the spinnerItems to the adapter:

[Activity(Label = "SpinnerActivity", MainLauncher = true)]
public class SpinnerActivity : Activity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        SetContentView(Resource.Layout.spinner);

        Spinner sp = FindViewById<Spinner>(Resource.Id.spinner);
        List<MySpinnerItem> spinnerItems = new List<MySpinnerItem>();
        spinnerItems.Add(new MySpinnerItem("Red-",Color.Red));
        spinnerItems.Add(new MySpinnerItem("Yellow--", Color.Yellow));
        spinnerItems.Add(new MySpinnerItem("Green-----", Color.Green));
        spinnerItems.Add(new MySpinnerItem("Blue---", Color.Blue));
        spinnerItems.Add(new MySpinnerItem("Black--------", Color.Black));
        var spinnerAdapter = new MyAdapter(this, Android.Resource.Layout.SimpleSpinnerItem, spinnerItems);
        sp.Adapter = spinnerAdapter;
    }
}

class MyAdapter : ArrayAdapter<MySpinnerItem>
{
    public Context context;
    public List<MySpinnerItem> list;
    public int textViewResourceId;
    public MyAdapter(Context context, int textViewResourceId, List<MySpinnerItem> objects) : base(context, textViewResourceId, objects)
    {
        this.context = context;
        list = objects;
        this.textViewResourceId = textViewResourceId;
    }

    public override View GetDropDownView(int position, View convertView, ViewGroup parent)
    {

        if (convertView == null)
        {
            LayoutInflater inflater = LayoutInflater.From(context);
            convertView = inflater.Inflate(textViewResourceId, parent, false);
        }
        TextView tv = (TextView)convertView.FindViewById(Android.Resource.Id.Text1);
        tv.Text = list[position].Text;
        convertView.SetBackgroundColor(list[position].Color);
        return convertView;
    }
    public override View GetView(int position, View convertView, ViewGroup parent)
    {

        if (convertView == null)
        {
            LayoutInflater inflater = LayoutInflater.From(context);
            convertView = inflater.Inflate(textViewResourceId, parent, false);
        }

        TextView tv = (TextView)convertView.FindViewById(Android.Resource.Id.Text1);
        tv.Text = list[position].Text;
        convertView.SetBackgroundColor(list[position].Color);
        return convertView;
    }
}

class MySpinnerItem
{
    public string Text;
    public Color Color;

    public MySpinnerItem(string text, Color color)
    {
        Text = text;
        Color = color;
    }
}