title: What is difference between tools:text and android:text in android
body: <p>i just came to know that we can set the text by using tools:text="toolsText".
  before this i was using android:text="androidText".</p>
  
  <p>Please tell me 
  1.what are differences between these two feature
  2.which one is best to use 
  3.What are there effect during ui rendering </p>