SupportMapFragment returning null [Android Studio] [kotlin]-CodePudding

im trying to fallow the google maps api guide on displaying a map in a fragment. But every time i call the support fragment manager it just keeps returning null to me. I don't know what im doing wrong and i thought my code was the same as the example.

. fragment:

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:id="@ id/map"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

MainActivity

class MainActivity : AppCompatActivity(), OnMapReadyCallback {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)

        val mapFragment = supportFragmentManager      // right here keeps returning null
                 .findFragmentById(R.id.map) as SupportMapFragment
        mapFragment.getMapAsync(this)

im sorry if this question is strange. im literally just figuring it out for the first time

CodePudding user response：

Try once

val mapFragment = supportFragmentManager
                .findFragmentById(R.id.map) as SupportMapFragment?
            mapFragment!!.getMapAsync(this)

CodePudding user response：

You can define the OnMapReadyCallback on the top of the file as follows:

private val callback = OnMapReadyCallback { googleMap ->
        //do your stuff
}

and in onViewCreated() :

  override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        val mapFragment = childFragmentManager.findFragmentById(R.id.map) as SupportMapFragment?
        mapFragment?.getMapAsync(callback)