J_Sizzle J_Sizzle - 4 months ago 90
Android Question

findFragmentById for SupportMapFragment returns null in Android Studio

Recently I migrated a project from Eclipse to Android Studio. Everything is setup and working fine except for my one fragment which uses a SupportMapFragment. The below findFragmentById (which worked when building in Eclipse) is now returning null :(

public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
SupportMapFragment m = ((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.safety_map));


snippet of xml...

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<fragment
android:id="@+id/safety_map"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginBottom="40dp"
map:cameraTargetLat="@string/livesafe_latitude"
map:cameraTargetLng="@string/livesafe_longitude"
map:uiZoomControls="false"
class="com.google.android.gms.maps.SupportMapFragment"/>


Here are my dependencies in my build.gradle:

dependencies {
//google analytics
compile 'com.google.apis:google-api-services-analytics:v3-rev103-1.19.0'
//support library for api 10
compile 'com.android.support:support-v4:21.0.0'
//google play services
compile 'com.google.android.gms:play-services:6.1.11'
compile project(':facebook')
compile files('libs/android-support-multidex.jar')
compile files('libs/aws-android-sdk-1.6.0-debug.jar')
compile files('libs/FlurryAnalytics_3.3.2.jar')
}


I haven't changed any code in the xml file or the Fragment class that previously worked in Eclipse.

Answer

Judging by the fact that you're overriding Fragment.onActivityCreated(), I take it that your layout containing the map fragment is the layout for your Fragment. In that case, the SupportMapFragment is a child fragment of your hosting Fragment. When you attempt to retrieve it, you're using the Activity FragmentManager. You should instead use your Fragment's FragmentManager:

For example, this:

SupportMapFragment m = ((SupportMapFragment) getActivity()
        .getSupportFragmentManager().findFragmentById(R.id.safety_map));

becomes:

SupportMapFragment m = ((SupportMapFragment) getChildFragmentManager()
        .findFragmentById(R.id.safety_map));