I created a completely new and empty FMX app, tried it using Delphi 10.3.3 and 10.4.0 (patch 3), and when installed on Android 7.1.2 devices (tried two different ones and the official simulator VM), after the splash screen this error message appears:
'java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.contains(java.lang.CharSequence)' on a null object reference'
The error message box flickers quickly (endless loop) and gets slower and slower and after a minute the complete device doesn't react anymore and I can only hard reset it.
I found this thread, so I'm not alone. They say it worked until Delphi 10.1.2. There are also many other similar search results.
Is there any solution? On other Android versions it works well.
Or what can I try to get more information about what causes it?
Do you know a good candidate for an app made with Firemonkey that I could download directly and try out on the device?
Now there is a fix available at quality.embarcadero.com!
Just one line has to be added to 'Androidapi.JNIBridge.pas'. I'm not sure if I should copy it here... Will update this answer when it is released.