Android SpannableString set background behind part of text

Question

I would like to create something similar as seen on this image:

I managed to create evertyhing with SpannableStringBuilder, except the orange rounded rectangle. I can set the background to that color with BackgroundColorSpan, but I can't find a way to make it rounded. Any ideas how can I achieve this?

Thanks in advance!

EDIT: I'm using Xamarin.Android, but here is my code:

stringBuilder.SetSpan(new BackgroundColorSpan(Application.Context.Resources.GetColor(Resource.Color.orangeColor)), stringBuilder.Length() - length, stringBuilder.Length(), SpanTypes.ExclusiveExclusive); 

Answer 1

If anyone's having difficulty with Roosevelt's code sample (I sure was, maybe because it's Xamarin.Android?), here's a translation into a more basic Android java version:

     public class RoundedBackgroundSpan extends ReplacementSpan {          private static int CORNER_RADIUS = 8;         private int backgroundColor = 0;         private int textColor = 0;          public RoundedBackgroundSpan(Context context) {             super();             backgroundColor = context.getResources().getColor(R.color.gray);             textColor = context.getResources().getColor(R.color.white);         }          @Override         public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {             RectF rect = new RectF(x, top, x + measureText(paint, text, start, end), bottom);             paint.setColor(backgroundColor);             canvas.drawRoundRect(rect, CORNER_RADIUS, CORNER_RADIUS, paint);             paint.setColor(textColor);             canvas.drawText(text, start, end, x, y, paint);         }          @Override         public int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm) {             return Math.round(paint.measureText(text, start, end));         }          private float measureText(Paint paint, CharSequence text, int start, int end) {             return paint.measureText(text, start, end);         }     } 

And for usage, the following code segment is taken from an Activity and basically puts a nice rounded-corner background around each tag string, with a spacial buffer in between each tag. Note that the commented out line just puts in a background color, which doesn't produce as nice a look...

     SpannableStringBuilder stringBuilder = new SpannableStringBuilder();      String between = "";     for (String tag : eventListing.getTags()) {        stringBuilder.append(between);        if (between.length() == 0) between = "  ";        String thisTag = "  "+tag+"  ";        stringBuilder.append(thisTag);        stringBuilder.setSpan(new RoundedBackgroundSpan(this), stringBuilder.length() - thisTag.length(), stringBuilder.length() - thisTag.length() + thisTag.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);        //stringBuilder.setSpan(new BackgroundColorSpan(getResources().getColor(R.color.gray)), stringBuilder.length() - thisTag.length(), stringBuilder.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);     }      TextView tv = new TextView(this);     tv.setText(stringBuilder); 

Answer 2

I managed to solve my problem, based on pskink's suggestion. Here is my class:

public class RoundedBackgroundSpan : ReplacementSpan {     public override void Draw(Canvas canvas, ICharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint)     {         var rect = new RectF(x, top, x + MeasureText(paint, text, start, end), bottom);         paint.Color = Application.Context.Resources.GetColor(Resource.Color.nextTimeBackgroundColor);         canvas.DrawRoundRect(rect, Application.Context.Resources.GetDimensionPixelSize(Resource.Dimension.localRouteDetailsRoundRectValue), Application.Context.Resources.GetDimensionPixelSize(Resource.Dimension.localRouteDetailsRoundRectValue), paint);         paint.Color = Application.Context.Resources.GetColor(Resource.Color.nextTimeTextColor);         canvas.DrawText(text, start, end, x, y, paint);     }      public override int GetSize(Paint paint, ICharSequence text, int start, int end, Paint.FontMetricsInt fm)     {         return Math.Round(MeasureText(paint, text, start, end));     }      private float MeasureText(Paint paint, ICharSequence text, int start, int end)     {         return paint.MeasureText(text, start, end);     } } 

Example usage:

var stringBuilder = new SpannableStringBuilder(); var stringToAppend = "hello world"; stringBuilder.Append(stringToAppend); stringBuilder.SetSpan(new RoundedBackgroundSpan(), stringBuilder.Length() - stringToAppend.Length, stringBuilder.Length(), SpanTypes.ExclusiveExclusive);