I used Google cast to cast my phone's screen. That worked. But all4, the Channel 4 catch-up app, wouldn't display on the second screen. A message popped up saying "all 4 doesn't work on secondary screens". Trying to cast from the all4 app threw "this is not available for cast".
Is there another app which can just cast the whole screen? The s5 screen mirroring didn't seem to detect the Chromecast at all. To be clear, I need an app which can cast the screen like Google cast does. An app which only casts local files or streams from specific providers is no good.
We're talking s5 android, touchwiz, rooted, xposed. If you have any idea how to stop Google cast from snitching to other apps, please let me know here: https://android.stackexchange.com/questions/157427/how-do-i-prevent-apps-from-blocking-a-second-screen
Edit: I've tried several apps from Play, including secondscreen, but they all just try to use the s5's native screen mirroring ability. This doesn't even detect my Chromecast. Don't know why, because the screen mirroring works fine on other tvs I've tried that have native screen mirroring. If other people can get it s5 native screen mirroring to talk to Chromecast, I'd love to know how they managed it! :-)