• Almost everybody agrees that a great design helps a lot to make people get interested in you app. If you don't agree, try to publish an app with a awful UI and see what happens…

• The huge majority of apps in Play Store uses Progress Dialog to show progress, but some high quality apps innovate with nice animations to show the user that he should wait. Let's see how to make a different loading animation: Morph a button into a loading spinner.

• Add the button in your layout file and customize it the way you like it.

<com.kotlinlibrary.buttonview.ProgressButton
        android:id="@+id/btn_normal"
        android:layout_width="0dp"
        android:layout_height="@dimen/_50sdp"
        android:gravity="center"
        android:text="@string/btn_normal"
        android:textColor="@color/colorLine"
        app:pb_normal_color="@color/colorAccent"
        app:pb_progress_style="dots"
        app:pb_progress_dots_count="2"
        app:pb_corner_radius="@dimen/_25sdp"
        app:pb_anim_corner_radius="@dimen/_25sdp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

Here there are define all property which are available and you have used it.

• Then, instantiate the button

   //Create variable and bind your xml component on that object.
   val buttonLogin = findViewById<RoundButton>(R.id.fab_login)

   //For start animation and display progress bar 
   buttonLogin.startAnimation()

   //For revert animation and stop to display progress bar
   buttonLogin.revertAnimation()

   //For stop animation
   buttonLogin.stopAnimation()

• Progress Button Shadow.
• Runtime Bonus.