Adding property selectedTextStyle

[alexkok]

Adding a property to define the text style to use when the button is in its selected state.

---

Hello,

Thanks for continuing the older repo.
With the many configuration options this component is great to customise!

While using this library, I was missing an option that I need: defining the text style for the selected button. So added this option to the library.

---

This Pull Request provides the option selectedTextStyle to the SegmentedButton:

• The available typeface options are the same as the ones for the app:textStyle
• By default, the selected text style is the text style as defined by the app:textStyle attribute.
• Also added a getter and setter for this, since all properties provide it like this
• Added the property to the README

[addisonElliott]

Hello, thanks for the contribution! It all looks good to me.

Do you mind adding an example demonstrating this capability? If you're comfortable with it, you can even include the exact setup you're using in code just to see some real-world usages.

If not, I can merge without an example.

[alexkok]

Thanks! As for the example, I've added it to the showcase of the Draggable Segmented Group in the sample app. The selected button of that row state gets the bold text on that set of buttons.

[addisonElliott]

Okay, works for me. I missed that the first time reading through the code.

Thanks for the contribution and sorry for the delay in merging it.

[alexkok]

No problem, thanks for merging and releasing it! 👍