This is based on an open source autosizing textview for Android I found a few weeks ago. The initial approach didn't resize multiple lines and wasn't maintained to keep up with changes in Android. I decided to go ahead and create this as a place to preserve the auto sizing text view as well as giving it a platform for some change and to possibly add some features and functionality.
To use the SizeAdjustingTextView make sure you have the custom view somewhere in your project. From there when using XML Layouts you can simply use the com.some.package.name.SizeAdjustingTextView widget and thats it. From there you need to make sure that you set a text size as the baseline for the view.
<com.example.sizeadjustingtextview.view.SizeAdjustingTextView
android:layout_width="fill_parent"
android:layout_height="100dp"
android:id="@+id/topBox"
android:layout_below="@id/text_input"
android:gravity="center"
android:padding="0dp"
android:textSize="60sp" />
Lastly when using custom views in XML, make sure you have the XLMNS tag in the root of the layout tag.
xmlns:app="http://schemas.android.com/apk/res/com.example.SizeAdjustingTextView"
I didn't want to make this a library because there is no need for adding a library for one view. Just port over the SizeAdjustingTextView and you should be good.