I need to change the color of the String which appears randomly in a sentence.

Ex: These following sentences are what I need to display.

1. hai **#xyz** how are you.
2. i am learning **#abc** android.

In this I have to change the color of the words "**#xyz**", "**#abc**" i.e, which starts with the character "**#**". 

I used some string functions split(), subString(). but I am not getting what i need.

so, please guide me how to solve this.