title: Dp unit does not scale layouts in different screens
body: <p>After reading this (<a href="http://developer.android.com/guide/practices/screens_support.html" rel="nofollow">http://developer.android.com/guide/practices/screens_support.html</a>), I have developed an entire app using the dp unit inside the xml files. However, when I test the app in different screens, the layouts are either too big or too small.</p>
  
  <p>I thought the dp unit would fix that for me. Why didn't it? I do not want to use the weight attribute since everything is already done.</p>
  
  <p>One xml layout:
          </p>
  
  <pre><code>&lt;ImageView
      android:layout_width="match_parent"
      android:layout_height="140dp"
      android:src="@drawable/logo3"
      android:scaleType="centerCrop"
  
      /&gt;
  
  &lt;TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/select_level"
      android:textColor="#4cb122"
      android:layout_gravity="center_horizontal"
      android:gravity="center_horizontal"
      android:textSize="20dp"
      android:layout_marginTop="20dp"
      /&gt;
  
  &lt;Button
      android:background="@drawable/red_button"
      android:layout_width="200dp"
      android:layout_height="55dp"
      android:layout_gravity="center_horizontal"
      android:layout_marginTop="25dp"
      android:text="@string/easy"
      android:textSize="15dp"
      android:onClick="playEasy"
      style="custom_button"
      /&gt;
  
  &lt;Button
      android:background="@drawable/green_button"
      android:layout_width="200dp"
      android:layout_height="55dp"
      android:layout_gravity="center_horizontal"
      android:layout_marginTop="10dp"
      android:text="@string/medium"
      android:textSize="15dp"
      android:onClick="playMedium"
      style="custom_button"
      /&gt;
  
  &lt;Button
      android:background="@drawable/blue_button"
      android:layout_width="200dp"
      android:layout_height="55dp"
      android:layout_gravity="center_horizontal"
      android:layout_marginTop="10dp"
      android:textSize="15dp"
      android:text="@string/unbeatable"
      android:onClick="playUnbeatable"
      style="custom_button"
      /&gt;
  
  &lt;TextView
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:gravity="center_horizontal"
      android:layout_marginTop="113dp"
      android:textSize="15dp"
      android:textColor="@color/secondTextColor"
      android:text="@string/developed_by"
      /&gt;
  </code></pre>
  
  <p></p>
  
  <p>What could I do? Thanks!</p>