how to change text color in the middle of the sentence in android

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.