Wear OS - settting up project with fragments-CodePudding

I'm trying to set up a Wear OS project. I have some experience with normal android development but Wear os is new for me.

I'm used to just having one MainActivity and some fragments. But I'm trying to make that work for Wear OS but with no success. It keeps crashing when I want to use viewBinding in the OverviewFragment.kt.

I got the following project now:

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.wear.widget.BoxInsetLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="@dimen/box_inset_layout_padding"
    tools:context=".MainActivity"
    tools:deviceIds="wear">

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="@dimen/inner_frame_layout_padding"
        app:layout_boxedEdges="left|right">

        <include
            layout="@layout/content_main"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </FrameLayout>
</androidx.wear.widget.BoxInsetLayout>

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.wear.widget.BoxInsetLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <fragment
        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:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/nav_graph" />
</androidx.wear.widget.BoxInsetLayout>

fragment_overview.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.OverviewFragment">

    <TextView
        android:id="@ id/tvOverview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clickable="true"
        android:text="overview"
        android:textAlignment="center" />

</FrameLayout>

MainActivity.kt

class MainActivity : FragmentActivity() {

    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)
    }
}

OverviewFragment.kt

class OverviewFragment : Fragment() {

    private var _binding: FragmentOverviewBinding? = null
    private val binding get() = _binding!!

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_overview, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        binding.tvOverview.setOnClickListener {
            println("great")
        }
    }
}

Just a simple design, but it does not like the binding.tvOverview.setOnClickListener part in OverviewFragment.kt. It just keeps crashing.

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.krakert.tracker, PID: 7261
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.krakert.tracker/com.krakert.tracker.MainActivity}: android.view.InflateException: Binary XML file line #17: Binary XML file line #8: Error inflating class fragment
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
        at android.app.ActivityThread.-wrap11(Unknown Source:0)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
        at android.os.Handler.dispatchMessage(Handler.java:105)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6541)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
     Caused by: android.view.InflateException: Binary XML file line #17: Binary XML file line #8: Error inflating class fragment
     Caused by: android.view.InflateException: Binary XML file line #8: Error inflating class fragment
     Caused by: java.lang.NullPointerException
        at com.krakert.tracker.ui.OverviewFragment.getBinding(OverviewFragment.kt:15)
        at com.krakert.tracker.ui.OverviewFragment.onViewCreated(OverviewFragment.kt:28)

I would like some help here, setting the project up. Really new to Wear OS

Thanks!

CodePudding user response：

Not sure how this can work and suspect this is where the NullPointerException comes from

    private var _binding: FragmentOverviewBinding? = null
    private val binding get() = _binding!!

compare to the example at https://developer.android.com/topic/libraries/view-binding#fragments

which sets _binding in onCreateView