I've had this problem too, both with relative layouts and linear layouts. It doesn't seem to be layout-related.
Here is an example to see the error, just with a simple layout, no code at all:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".FechaHoraActivity" >
<TimePicker
android:id="@+id/timePicker1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp" />
<CalendarView
android:id="@+id/calendarView1"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
And now just change the linear layout height to:
android:layout_height="match_parent"
With this change the problem is gone, at least in my Samsung Galaxy Tab 2
So it seems it is more "space" related, but I'm still not sure why this problem appears. And I haven't found any other interesting results on google searching "calendarview slow"...
EDIT Let's see if we can find an answer with a small bounty
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