title: How to properly remove padding (or margin?) around buttons in Android?
body: <p>Currently, I have the following bottom log in button.</p>
  
  <h2>When button is not being pressed</h2>
  
  <p><a href="https://i.stack.imgur.com/WUs96.png" rel="noreferrer"><img src="https://i.stack.imgur.com/WUs96.png" alt="enter image description here"></a></p>
  
  <h2>When button is being pressed</h2>
  
  <p><a href="https://i.stack.imgur.com/j5VYK.png" rel="noreferrer"><img src="https://i.stack.imgur.com/j5VYK.png" alt="enter image description here"></a></p>
  
  <p>The XML looks like this</p>
  
  <pre><code>&lt;LinearLayout
      android:background="?attr/welcomeBottomNavBarBackground"
      android:orientation="horizontal"
      android:id="@+id/sign_in_bottom_nav_bar"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:layout_alignParentBottom="true"&gt;
      &lt;Button
          style="?android:attr/buttonBarButtonStyle"
          android:id="@+id/sign_in_button"
          android:layout_width="0dp"
          android:width="0dp"
          android:layout_weight="1.0"
          android:layout_height="48dp"
          android:gravity="center"
          android:layout_gravity="center"
          android:enabled="true"
          android:textAllCaps="true"
          android:text="@string/log_in" /&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>I would like to remove the padding (Or should I call it margin? Please refer to my bottom most p/s section) around button when it is being pressed.</p>
  
  <p>I look at <a href="https://stackoverflow.com/questions/17960599/how-to-remove-padding-around-buttons-in-android">How to remove padding around buttons in Android?</a></p>
  
  <p>I had tried</p>
  
  <pre><code>&lt;Button
      ...
      ...
      android:minHeight="0dp"
      android:minWidth="0dp" /&gt;
  </code></pre>
  
  <p>It doesn't work and has no effect.</p>
  
  <hr>
  
  <p>I further try</p>
  
  <pre><code>&lt;Button
      ...
      ...
      android:background="@null"
      android:minHeight="0dp"
      android:minWidth="0dp" /&gt;
  </code></pre>
  
  <p>No more padding when pressed. However, the material designed pressed visual effect will gone too.</p>
  
  <p>May I know what is the best way to remove button padding during pressed, yet retain the material designed pressed visual effect?</p>
  
  <h2>P/S</h2>
  
  <p>I don't really know whether I should call it padding or margin. What I wish to achieve is that, when we press on the bottom region, press visual effect change should be covered entire 100% bottom bar region (<code>@+id/sign_in_bottom_nav_bar</code>), instead of current 95% bottom bar region.</p>