AndroidアプリのKotlin移行時に遭遇した問題と対処例

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Ad

Android Kotlin
2017.06.29
Kenichi Kambara (@korodroid)
6 Kotlin

About me
•
•
• Droidcon Stockholm 2014
• Droidcon Spain 2014
• Droidcon Amsterdam 2013
• Droidcon Paris 2013
• Smartphone ...

Introduction
• Kotlin
•

Kotlin

Qiita ( )

Kotlin
- : All Java
- OSS: DataBinding / Retroﬁt
Kotlin
- : All Kotlin
- OSS:
Kotlin

Kotlin
[Menu]Code->Convert Java File to Kotlin File

(^^)v

(><)

Error:Circular dependency
between the following tasks:
:app:compileDebugKotlin

Error:Circular dependency
between the following tasks:
:app:compileDebugKotlin

Gradle Plugin

Gradle Plugin
(3.0.0-alpha3 )

Caused by: java.lang.IllegalArgumentException:
Parameter speciﬁed as non-null is null: method
kotlin.jvm.internal.Intrinsi...

Caused by: java.lang.IllegalArgumentException:
Parameter speciﬁed as non-null is null: method
kotlin.jvm.internal.Intrinsi...

Kotlin Nullable
NotNull

Nullable ( ? )
※ ( )

Unresolved reference: databinding
Unresolved reference: ActivityMainBinding
…

Unresolved reference: databinding
Unresolved reference: ActivityMainBinding
…

Kotlin Java

GenerateStubs
App build.gradle
android { 
…
kapt {
generateStubs = true
}
…
}

Cannot access 'binding': it is
private in 'ViewBindingHolder'

Cannot access 'binding': it is
private in 'ViewBindingHolder'

binding
private

private

Platform declaration clash: The following
declarations have the same JVM signature
(getRetrofit()Lretrofit2/Retrofit;):

Platform declaration clash: The following
declarations have the same JVM signature
(getRetrofit()Lretrofit2/Retrofit;):

Kotlin getter/setter
getter/setter

e.g.) getRetroﬁt→getRetroﬁtInstance

Smart cast to 'Retroﬁt' is impossible,
because 'retroﬁt' is a mutable property
that could have been changed by this time

Smart cast to 'Retroﬁt' is impossible,
because 'retroﬁt' is a mutable property
that could have been changed by this time

SmartCast

)Smart Cast

Smart Cast
fun demo(x: Any) {
if (x is String) {
print(x.length)
}

Smart Cast
fun demo(x: Any) {
if (x is String) {
print(x.length) //
}

Smart Cast
fun demo(x: Any) {
if (x is String) {
print(x.length) // Kolin
}

Conclusion (Kotlin )
•
• Kotlin
• ( )  
or Kotlin

Appendix

- Please let me know if you have any requests  
such as technical speeches, technical writings and so on.
Facebook:http://...

Share Slideshare

LinkedIn
Facebook
Twitter

Embed

Size (px)

Show related Slideshows at end

WordPress Shortcode

Link

Share
Email

2024 Trend Updates: What Really Wor... by Search Engine Jou... 1035460 views
Storytelling For The Web: Integrate... by Chiara Aliotta 947335 views
Artificial Intelligence, Data and C... by OECD Directorate ... 869118 views
How to Leverage AI to Boost Employe... by SocialHRCamp 364901 views
2024 State of Marketing Report – by... by Marius Sescu 207323 views
Everything You Need To Know About C... by Expeed Software 227648 views

View on Slideshare

1 of 42 Ad

View on Slideshare

1 of 42 Ad