How to align linearlayout to vertical center?

Change orientation and gravity in

<LinearLayout
    android:id="@+id/groupNumbers"
    android:orientation="horizontal"
    android:gravity="center_vertical"
    android:layout_weight="0.7"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

to

android:orientation="vertical"
android:layout_gravity="center_vertical"

You are adding orientation: horizontal, so the layout will contain all elements in single horizontal line. Which won't allow you to get the element in center.

Hope this helps.

use android:layout_gravity instead of android:gravity

android:gravity sets the gravity of the content of the View its used on. android:layout_gravity sets the gravity of the View or Layout in its parent.

Use layout_gravity instead of gravity. layout_gravity tells the parent where it should be positioned, and gravity tells its child where they should be positioned.

<LinearLayout
    android:id="@+id/groupNumbers"
    android:orientation="horizontal"
    android:layout_gravity="center_vertical"
    android:layout_weight="0.7"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

For me, I have fixed the problem using android:layout_centerVertical="true" in a parent RelativeLayout:

<RelativeLayout ... >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_centerVertical="true">

</RelativeLayout>