Chromecast Button only appears after backgrounding the app

Question

Pretty simple situation. Adding a Chromecast button to the toolbar. When the app is first launched, the button does not appear. When I background the app and then bring it to the foreground again, the button appears. And yes, there is a castable device on the same wifi network.

MyFragment.kt

override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {

    inflater.inflate(R.menu.toolbar_menu, menu)

    CastButtonFactory
        .setUpMediaRouteButton(context?.applicationContext, menu, R.id.media_route_menu_item)

    return super.onCreateOptionsMenu(menu, inflater)
}

toolbar_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/media_route_menu_item"
        android:title="@string/media_route_menu_title"
        app:actionProviderClass="androidx.mediarouter.app.MediaRouteActionProvider"
        app:showAsAction="always" />
</menu>

Seems like that should do it. I have the CastOptionsProvider class setup with the correct receiver id. This is a debug build, so there is no proguard.

Note that the button does eventually appear, but only after I background/foreground the app. I can wait for 10 minutes and nothing happens. But if I background/foreground, the button is visible immediately.

EDIT:
Big thanks to @fllo for the answer. There is a little more in his suggestion than was ultimately required, so I wanted to clarify for others.

The code that I posted was fine. All I was missing was simply to initialize the CastContext in onCreate() of the Activity. Makes perfect sense if I had just thought about it.

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    CastContext.getSharedInstance(this)
}

So that's it. Easy solution. Hope it helps someone.

score 2 · Accepted Answer · answered Nov 19 '19 at 12:38

2

You need to make sure the Cast SDK is initialized before your Fragment instance is created.

Moving the Cast SDK initialisation code (CastButtonFactory with setUpMediaRouteButton(), CastStateListener and IntroductoryOverlay) into the parent Activity will work as expected. Then, maybe just hide by default the MenuItem and show it from your Fragment should do the trick.

According to the documentation, the MediaRouteButton should be in a FragmentActivity. My guess is the callbacks are not called from a Fragment, then, its visibility doesn't change dynamically. So you will need to cast it from the Activity and passing down to the Fragment when receiving an update. Not very elegant but it should work.

answered Nov 19 '19 at 12:38

Blo

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2

Thanks. This is mostly right and resolved my issue. The problem was really simple. I wasn't calling `CastContext.getSharedInstance(this)` early enough, as you alluded to. The callbacks and listeners didn't have anything to do with it and I don't need to pass it to a fragment. – AndroidDev Nov 19 '19 at 17:09
Thanks very much for help. I'm going to update my OP with the final solution to clarify for others. Much appreciated! – AndroidDev Nov 19 '19 at 17:09
1

We also experienced this issue when using the Cast SDK for a React Native application and found that in order for local Cast receiver devices to be recognized we had to call `CastContext.getSharedInstance(this)` in the `onCreate` of the native host application, rather than waiting until `createViewInstance` on the React Native module to call it. – Jadent Aug 10 '20 at 13:45

Chromecast Button only appears after backgrounding the app

1 Answers1