Google IO Extended: Android JetPack: Navigation Component

A brief overview of the Navigation Component presented at Google IO Extended at the Google office in Berlin.

Transcript

1. Android JetPack
   Navigation Component
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2. @askashdavies
   

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3. @askashdavies
   

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4. !
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5. "Once we have gotten in to this entry-point to
   your UI, we really don't care how you organise the
   flow inside."
   — Dianne Hackborn, Android Framework team
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6. !
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8. JetPack: Navigation
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9. JetPack: Navigation
   • Libraries
   !
   • Plugin
   "
   • Tooling
   #
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10. • Fragment transactions
    • Up and back actions
    • Standardised transition resources
    • Deep link implementation
    • Easy navigation patterns
    • Type safe arguments
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11. Principles of Navigation
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12. JetPack: Navigation
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13. Navigation Graph
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15. NavHostFragment
    android:id="@+id/nav_host_fragment"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:defaultNavHost="true"
    app:navGraph="@navigation/nav_graph" />
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16. NavController
    • Fragment.findNavController()
    • View.findNavController()
    • Activity.findNavController(viewId: Int)
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17. !
    SafeArgs
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18. SafeArgs: Directions
    MainFragmentDirections.mainToViewBalance()
    android:id="@+id/fragmentMain"
    android:name="com.google.sample.MainFragment"
    android:label="@string/main_title"
    tools:layout="@layout/main_fragment">
    android:id="@+id/mainToViewBalance"
    app:destination="@+id/fragmentViewBalance"/>
    
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19. SafeArgs: Directions
    android:id="@+id/fragmentViewBalance"
    android:name="com.google.sample.ViewBalanceFragment"
    android:label="@string/view_balance_title"
    tools:layout="@layout/view_balance_fragment">
    android:name="balanceAmount"
    app:argType="integer"/>
    
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20. SafeArgs: Args
    class MainFragment: Fragment() {
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    viewTransactionsButton.setOnClickListener { view ->
    MainFragmentDirections.mainToViewBalance(100)
    }
    }
    }
    class ViewBalanceFragment : Fragment() {
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    val args = ViewBalanceFragmentArgs.fromBundle(arguments!!)
    balance.setText(String.format("%.2d", args.balanceAmount))
    }
    }
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21. SafeArgs: Getting Started
    buildscript {
    repositories {
    google()
    }
    dependencies {
    classpath "androidx.navigation:navigation-safe-args-gradle-plugin:2.0.0"
    }
    }
    apply plugin: 'androidx.navigation.safeargs.kotlin'
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22. !
    Migrating
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23. !
    Migrating
    • Move screen behaviour away from activities
    • Create new activity for NavHostFragment
    • Move existing activity logic to fragment
    • Initialise fragment in host activity
    • Pass arguments as necessary
    • Create navigation graph
    • Profit
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24. !
    Scoping
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25. @askashdavies
    

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26. @askashdavies
    

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27. Ian Lake: Single Activity: Why, When, and How
    bit.ly/2Jo94x9
    

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28. Thanks!
    bit.ly/2V6HZk4
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