This document outlines an Android study jam session on navigation, fragments, and activity and fragment lifecycles. It introduces fragments and the navigation component in Android and explains the lifecycles of activities and fragments. It also discusses logging with Log and Timber and using Safe Args to pass arguments between fragments. The session aims to help participants learn Kotlin and build Android apps through coding labs and sharing demos.

1. This work is licensed under the Apache 2.0 License
Android Study Jams
Prior Programming Experience Track: Session 2
Navigation
Activity and Fragment Lifecycles

2. This work is licensed under the Apache 2.0 License
About Me
Roman Jaquez
● Mobile Developer (Flutter, Android, IOS)
● Google Cloud Certified Architect
● GDG Lawrence Lead
● GDG Northeast Mentor
@drcoderz

3. This work is licensed under the Apache 2.0 License
Learning Objectives
० Learn the essentials of the Kotlin programming language
० Build a variety of Android apps
० Best practices for Android development
० Discover resources to continue learning

4. This work is licensed under the Apache 2.0 License
० Join the Slack #studyjam2021 channel to share your progress
https://shorturl.at/dpsRV
० The labs are online, take your time
० Create an app to demo and share in the last session
० Win a raffle prize, compete in the demos
० Earn this certificate of completion
Learn with the Boston Android Group

5. This work is licensed under the Apache 2.0 License

6. This work is licensed under the Apache 2.0 License
Codelab 1: Navigation
https://developer.android.com/courses/pathways/kotlin-fundamentals-four
Codelab 2: Activity and Fragment
https://developer.android.com/courses/pathways/kotlin-fundamentals-five
Android Study Jams
Prior Programming Experience
Track
Session 2

7. This work is licensed under the Apache 2.0 License
Commit to 4 Mondays
SEP 20, Koans - Studio, XML layout
SEP 27, Activity/Fragment basics
OCT 4, LiveData and ViewModel!!
OCT 11, Databases, Design

8. This work is licensed under the Apache 2.0 License
Logistics

9. This work is licensed under the Apache 2.0 License
Be excellent to each other. Treat everyone
with respect, everyone deserves to be here.
Consider what you are saying and how it
would feel if it were said to you.
Speak up if you see or hear something. If
someone is making you feel uncomfortable
they may not intend to do that. Politely
letting them know is encouraged.
https://developers.google.com/community-guidelines

10. This work is licensed under the Apache 2.0 License
The plan
● 90 mins
● Work at your own pace
● Full path? g.co/android/studyjams
● Each session will end with a Door Prize
● Demo at the final session - the best can
win Google Pixel Buds
Tonight’s prize
Google Nest Mini

11. This work is licensed under the Apache 2.0 License
Use the Slack Team
#studyjam2021
Find us on Twitter
@bostonandroid
Tag @GDG
Share what you’ve learned
with #AndroidStudyJams

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QUICK ANDROID TRIVIA
How well do you know Android?

13. Android 8 (O) is called
ⓘ Start presenting to display the poll results on this slide.

14. Android 9 (P) is called
ⓘ Start presenting to display the poll results on this slide.

15. Android 10 (Q) is called
ⓘ Start presenting to display the poll results on this slide.

16. Android 11 (R) is called
ⓘ Start presenting to display the poll results on this slide.

17. Android 12 (S) is called
ⓘ Start presenting to display the poll results on this slide.

18. Android 13 (T) is called
ⓘ Start presenting to display the poll results on this slide.

19. When did the Android come
out in the US?
ⓘ Start presenting to display the poll results on this slide.

20. The first iPhone from Apple came
out in June 2007. Who made the
first Android phone?
ⓘ Start presenting to display the poll results on this slide.

21. This work is licensed under the Apache 2.0 License
Let’s Start!

22. This work is licensed under the Apache 2.0 License
Android Fragments
A Fragment represents a behavior or a portion of user interface (UI) in an
Activity.
● You can combine multiple fragments in a single activity to build a multi-pane UI
● You can reuse a Fragment in multiple activities.
● A Fragment has its own lifecycle and receives its own input events
● You can add / remove a Fragment while an activity is running
● A Fragment is defined in a Kotlin class
● A Fragment’s UI is defined in an XML layout file

23. This work is licensed under the Apache 2.0 License
The Navigation component is a library that can manage complex navigation,
transition animation, deep linking, and compile-time checked argument passing
between the screens in your app.
Navigation Components in Android

24. This work is licensed under the Apache 2.0 License
A navigation host fragment acts as a host for the fragments in a navigation
graph. The navigation host Fragment is usually named NavHostFragment.
● As the user moves between destinations defined in the navigation graph,
the navigation host Fragment swaps fragments in and out as necessary.
● The Fragment also creates and manages the appropriate Fragment back
stack.
NavHostFragment

25. This work is licensed under the Apache 2.0 License
Lifecycles in Android / Activity Lifecycle

26. This work is licensed under the Apache 2.0 License
Lifecycles in Android / Fragment Lifecycle

27. This work is licensed under the Apache 2.0 License
Log is the default Android Logging API.
● Enables you to write short messages that are displayed in the Logcat with
Android Studio
● Use Log.i() to write an informational message. Takes two parameters:
○ tag: the name of the class
○ message: a short string
● Use the Logcat page in Android Studio to view system logs
Logging using Log

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Timber is a popular logging library.
● Has several advantages over the built-in Android Log class.
● Generates the log tag for you based on the class name
● Helps you avoid showing logs in a release version of your Android app
● Allows for integration with crash-reporting libraries
● Use Timber.i() to write log messages. Takes only one parameter:
○ message: the message to write
○ tag: (name of the class) is added automatically
Logging using Timber

29. This work is licensed under the Apache 2.0 License
To help catch errors caused by missing keys or mismatched types when you
pass data from one Fragment to another, use a Gradle plugin called Safe Args.
● For each Fragment in your app, the Safe Args plugin generates a
corresponding NavDirection class. You add the NavDirection class to the
Fragment code, then use the class to pass arguments between the
Fragment and other fragments.
● The NavDirection classes represent navigation from all the app's actions.
Safe Args

30. This work is licensed under the Apache 2.0 License
● An implicit intent declares an action that your app wants some other app
(such as a camera app or email app) to perform on its behalf.
● If several Android apps could handle an implicit intent, Android shows the
user a chooser.
Implicit Intents

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● Explicit Intents specify which application will satisfy the intent, by supplying either the
target app's package name or a fully-qualified component class name
● PendingIntent is a token that you give to a foreign application (e.g. NotificationManager ,
AlarmManager , Home Screen AppWidgetManager , or other 3rd party applications),
which allows the foreign application to use your application's permissions to execute a
predefined piece of code.
● Extras are a form of key — value pairs that give your intent additional information to
complete its action.
a. putExtras() / getExtras()
Other Types of Intents

32. This work is licensed under the Apache 2.0 License
Prior Programming Experience Track: Session 2
Android Study Jams

33. This work is licensed under the Apache 2.0 License
Want to learn more?
● Official Android Developers Site: https://developer.android.com/
● Android Samples on GitHub
● Official Android Developers Blog (for announcements)
● Android Developers Medium Blog (for more technical articles)
● Android Developers YouTube channel
● Follow @AndroidDev on Twitter
● Subscribe to the Android Developer Newsletter
● Kotlin Vocabulary series
● Official Kotlin language site
Version 1.0

34. This work is licensed under the Apache 2.0 License
Thank you!!!