title: setting transparency to buttons in android
body: <p>I want to make Buttons with different transparency levels in android.I have used <code>"@android:color/transparent"</code>. But it makes the button 100% transparent. I need a 70% transparent button. Here is the XML code that I am working on:</p>
  
  <pre><code>&lt;LinearLayout 
      android:layout_width="fill_parent" 
      android:layout_height="wrap_content"
      android:gravity="center" 
      android:layout_weight="1"&gt;
  
      &lt;Button android:id="@+id/one" 
          android:text="@string/dtmf_1"
          android:layout_width="fill_parent" 
          android:layout_height="fill_parent"
          android:layout_weight="1" 
          android:textColor="@color/white" &gt;&lt;/Button&gt;
      &lt;Button android:id="@+id/two"  
          android:text="@string/dtmf_2"
          android:layout_width="fill_parent" 
          android:layout_height="fill_parent"
          android:layout_weight="1"  
          android:textColor="@color/white" &gt;&lt;/Button&gt;
      &lt;Button android:id="@+id/three" 
          android:text="@string/dtmf_3"
          android:layout_width="fill_parent" 
          android:layout_height="fill_parent"
          android:layout_weight="1"  
          android:textColor="@color/white" &gt;&lt;/Button&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>