I am currently working on the transition effects for my dialog. Please refer to the image below: 
The entrance animation for my dialog should be top to middle. While the exit animation should be middle to top. I am using the following XML animations, but unfortunately, they’re not working.
slide_down.xml
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<translate android:fromYDelta="100%p" android:toYDelta="0"
android:duration="1000"/>
</set>
slide_up.xml
<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
android:fromYDelta="0%p" android:toYDelta="50%p"
android:duration="1000"/>
EDIT: This is not a usual Dialog. It is an activity applied with a Theme.Dialog in the AndroidManifest.xml
if you are creating the dialog as an activity then you can follow this approach
You can create the animation classes :
and :
and use them with your Dialog