Android relative layout center vertical with margin

Try this:

Try to use RelativeLayout which can easily done your requirement using weight :

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_vertical">
      <TextView
          android:id="@id/dummy"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_centerVertical="true"
          android:layout_centerHorizontal="true" />
      <TextView
          android:layout_below="@id/dummy"
          android:layout_marginTop="10dp"
          android:text="This is TextView"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"/>
</RelativeLayout>

Try to use LinearLayout which can easily done your requirement using weight :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:gravity="center_vertical">
        <TextView
            android:text="This is TextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
    </LinearLayout>
</LinearLayout>

Why should add nested view inside parent view ?

Use paddingTop attribute.

Example:

<RelativeLayout
    android:id="@+id/rlParentView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">


    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:paddingTop="10dp"/>

</RelativeLayout>

Hope this will help you.