swissknife-navigation

Navigation Module

It contains the core extensions needed when you are dealing with the Android Navigation Component.

Dependencies:

• Navigation Fragment Dependency (androidx.navigation:navigation-fragment-ktx).
• Core Module

Module's content:

NavigationExtensions

A series of extensions to navigate safely. Suppose that you have a button that navigates from the screen A to the screen B. If the user clicks this button twice quickly, the first time will navigate from A to B. However, the second one the navigation component will try to navigate from A to B making crash the app because the current node is B. These extensions help to avoid these cases.

Keep Nav State

This package, contains the KeepStateNavigator class, which saves the Fragment state, when the fragment is removed from the Fragment Manager. The navigator defines the keep_state_fragment tag, that should be used in the navigation graph to indicates to use this Navigator. For example, your graph will look something like:

To use the KeepStateNavigator, you can add the controller manually in your NavHostFragment or use the KeepStateNavHostFragment, a NavHostFragment witch provides KeepStateNavigator support. A common use of this tool is when you have a fragment that contains multiple fragments that can change and you don't want to lose the child Fragment's state. The parent fragment can define the child navigation fragment as:

<fragment
    android:id="@id/keepStateNavHostContentFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:name="com.xmartlabs.swissknife.navigation.keepNavState.KeepStateNavHostFragment"
    app:navGraph="@navigation/nav_graph"
    />

The Navigation graph will look like:

<navigation
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/nav_graph"
    app:startDestination="@id/fragmentA"
    >

    <keep_state_fragment
        android:id="@+id/fragmentA"
        android:name="...FragmentA"
        android:label="FragmentA"
        />

    <keep_state_fragment
        android:id="@+id/fragmentB"
        android:name="...FragmentB"
        android:label="FragmentB"
        />


    <action
        android:id="@+id/action_display_fragment_a"
        app:destination="@id/fragmentA"
        />

    <action
        android:id="@+id/action_display_fragment_b"
        app:destination="@id/fragmentB"
        />

</navigation>