A simple implementation of onMeasure

Implementing a SquareFrameLayout.

Covariant return types for View’s onSaveInstanceState

When implementing custom Views that use the onSaveInstanceState hook, consider exposing the final Parcelable implementation.

Optimized Android Parcelable Reading and Writing

Use Parcelable.Creator.createFromParcel(...) and Parcelable.writeToParcel(...) instead of Parcel.readParcelable(...) and Parcel.writeParcelable(...).