Question

I want to create rounded buttons in an Android program. I have looked at How to create EditText with rounded corners?

What I want to achieve is:

1. Rounded Edge Buttons
2. Change Button background/appearance on different states (Like Onclick, Focus)
3. Use my own PNG for the background and not create a shape.

Answer 1

You can do a rounded corner button without resorting to an ImageView.

A background selector resource, button_background.xml:

<?xml version="1.0" encoding="utf-8" ?> 
     <selector xmlns:android="http://schemas.android.com/apk/res/android">
     <!--  Non focused states 
      --> 
      <item android:state_focused="false" android:state_selected="false" android:state_pressed="false" android:drawable="@drawable/button_unfocused" /> 
      <item android:state_focused="false" android:state_selected="true" android:state_pressed="false" android:drawable="@drawable/button_unfocused" /> 
     <!--  Focused states 
      --> 
      <item android:state_focused="true" android:state_selected="false" android:state_pressed="false" android:drawable="@drawable/button_focus" /> 
      <item android:state_focused="true" android:state_selected="true" android:state_pressed="false" android:drawable="@drawable/button_focus" /> 
     <!--  Pressed 
      --> 
      <item android:state_pressed="true" android:drawable="@drawable/button_press" /> 
    </selector>

For each state, a drawable resource, e.g. button_press.xml:

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
  <stroke android:width="1dp" android:color="#FF404040" /> 
  <corners android:radius="6dp" /> 
  <gradient android:startColor="#FF6800" android:centerColor="#FF8000" android:endColor="#FF9700" android:angle="90" /> 
</shape>

Note the corners element, this gets you rounded corners!

Then set the background drawable on the button:

android:background="@drawable/button_background"

EDIT (9/2018): The same technique can be used to create a circular button. A circle is really just a square button with radius size set to 1/2 the side of the square

Additionally, in the example above the stroke and gradient aren’t necessary elements, they are just examples and ways that you’ll be able to see the rounded corner shape