Everyday Kotlin

A collection of little things that stand

Transcript

1. Everyday Kotlin All kinds of little things that stand out René de Groot
2. Nullability • Natural next step after @NonNull and @Nullable • Your new BFF’s: late init, smart cast, guard
3. late init • Great for annotation processors filled fields
4. smart cast • You checked already, so get on with it • Query returns @Nullable Cursor 
 Which in Kotlin terms is Cursor? 
 Smart cast casts this to Cursor
 (Which in Java would be @Nonnull Cursor)

5. guard • Smart cast is impossible, because a mutable property could have been changed by this time
6. Joy, Pain, Joy, Pain ;
7. Expression bodies - @Provides • Old Java-style works fine • After a while it will itch
8. Mockito - Final • Mocking final classes needs some magic • Recent Mockito allow final mocking
9. Mockito/Hamcrest - Syntax • Function name when clashes with keyword • Function name is clashes with keyword • Using back ticks
10. any()-matcher • java.lang.IllegalStateException: ArgumentMatchers.any() must not be null • Roll a NonNull variant • Some Kotlin specific high-level Mockito methods
 https://github.com/nhaarman/mockito-kotlin
11. Thanks! • So much more … • Everyday Kotlin, what stands out for you?