title: Can not handle font size in all screen size
body: <p>I am building an Android application that will work on all screen sizes, I am using sp for the text size but there is a problem with the font size on different android screens. </p>
  
  <p>The attached photo for a tablet 10 inch, can anyone help me?</p>
  
  <p>screenshot:</p>
  
  <p><img src="https://i.stack.imgur.com/gokwv.png" alt="screenshot"></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
      &lt;android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:app="http://schemas.android.com/apk/res-auto"
          xmlns:tools="http://schemas.android.com/tools"
          android:layout_width="match_parent"
          android:layout_height="match_parent"&gt;
  </code></pre>
  
  <p>// In this TesxtView i used sp instead of dp.</p>
  
  <pre><code>    &lt;TextView
          android:id="@+id/username"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginBottom="@dimen/_6sdp"
          android:layout_marginEnd="@dimen/_6sdp"
          android:layout_marginLeft="@dimen/_6sdp"
          android:layout_marginRight="@dimen/_6sdp"
          android:layout_marginStart="@dimen/_6sdp"
          android:layout_marginTop="@dimen/_110sdp"
          android:text="Username"
          android:textAlignment="center"
          android:textColor="#FFFFFF"
          android:textSize="18sp"
          app:layout_constraintEnd_toEndOf="@+id/rectangle_login"
          app:layout_constraintLeft_toLeftOf="@+id/rectangle_login"
          app:layout_constraintRight_toRightOf="@+id/rectangle_login"
          app:layout_constraintStart_toStartOf="@+id/rectangle_login"
          app:layout_constraintTop_toTopOf="@+id/rectangle_login" /&gt;
  
  
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>