title: White color not visible in toolbar
body: <p>I have a green toolbar in my layout and I inserted a textview into it to center the text horizontally. I want the text of the toolbar to be white and I choose the color white for that. However, the white text is barely visible. Can anyone help? I'd appreciate it. </p>
  
  <p><a href="https://i.stack.imgur.com/gVPQm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gVPQm.png" alt="enter image description here"></a></p>
  
  <p>Here is the XML code of the TextView:</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"
  
  
      tools:context=".MainActivity"
      tools:ignore="ExtraText"&gt;
  
  
  
  
      '&lt;!--Learning: The following lines define a toolbar --&gt;'
  
      &lt;android.support.v7.widget.Toolbar
          android:id="@+id/toolbar_mainActivity"
          android:layout_width="match_parent"
          android:layout_height="53dp"
          android:background="#435cb53f"
          android:elevation="4dp"
          android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintHorizontal_bias="0.0"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintVertical_bias="0.0"
          app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
          app:titleTextColor="@android:color/holo_green_light" /&gt;
  
  
      &lt;Button
          android:id="@+id/Bestellen_Button"
          android:layout_width="255dp"
          android:layout_height="96dp"
          android:layout_marginBottom="8dp"
          android:layout_marginEnd="8dp"
          android:layout_marginLeft="8dp"
          android:layout_marginRight="8dp"
          android:layout_marginStart="8dp"
          android:layout_marginTop="8dp"
          android:text="@string/Bestellen_Button"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintHorizontal_bias="0.584"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintVertical_bias="0.461" /&gt;
  
      &lt;Button
          android:id="@+id/Statistik_Button"
          android:layout_width="256dp"
          android:layout_height="95dp"
          android:layout_marginBottom="8dp"
          android:layout_marginEnd="8dp"
          android:layout_marginLeft="8dp"
          android:layout_marginRight="8dp"
          android:layout_marginStart="8dp"
          android:layout_marginTop="8dp"
          android:text="@string/Statistik_Button"
          android:background="@android:color/transparent"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintVertical_bias="0.875" /&gt;
  
      &lt;ImageButton
          android:id="@+id/imageButton"
          android:layout_width="147dp"
          android:layout_height="wrap_content"
          android:layout_marginBottom="8dp"
          android:layout_marginEnd="80dp"
          android:layout_marginLeft="8dp"
          android:layout_marginRight="80dp"
          android:layout_marginStart="8dp"
          android:layout_marginTop="8dp"
          android:background="@android:color/transparent"
          android:contentDescription="Test"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintHorizontal_bias="0.744"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintVertical_bias="0.203"
          app:srcCompat="@mipmap/ic_launcher_round" /&gt;
  
      &lt;android.support.constraint.Guideline
          android:id="@+id/guideline"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:orientation="horizontal"
          app:layout_constraintGuide_begin="153dp" /&gt;
  
      &lt;TextView
          android:id="@+id/textView_ToolBar_MainActivity"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginBottom="8dp"
          android:layout_marginEnd="8dp"
          android:layout_marginLeft="8dp"
          android:layout_marginRight="8dp"
          android:layout_marginStart="8dp"
          android:layout_marginTop="8dp"
          android:text="TestText"
          android:textColor="@android:color/white"
          android:textSize="24sp"
          android:visibility="visible"
          app:fontFamily="@font/roboto_bold"
          app:layout_constraintBottom_toBottomOf="@+id/toolbar_mainActivity"
          app:layout_constraintEnd_toEndOf="parent"
          app:layout_constraintHorizontal_bias="0.535"
          app:layout_constraintStart_toStartOf="@+id/toolbar_mainActivity"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintVertical_bias="0.421"
          tools:text="TestText" /&gt;
  
  
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>