On the master branch @ d2b8c5e1234cdaff84bd1f60aea598d219cdac5e, building the apk target fails:
$ make -C src/qt apk
...
> Task :compileDebugJavaWithJavac FAILED
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/QtActivityDelegate.java:690: error: cannot find symbol
Display display = (Build.VERSION.SDK_INT < Build.VERSION_CODES.R)
^
symbol: variable R
location: class VERSION_CODES
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/QtActivityDelegate.java:692: error: cannot find symbol
: m_activity.getDisplay();
^
symbol: method getDisplay()
location: variable m_activity of type Activity
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/QtActivityDelegate.java:833: error: cannot find symbol
float refreshRate = (Build.VERSION.SDK_INT < Build.VERSION_CODES.R)
^
symbol: variable R
location: class VERSION_CODES
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/QtActivityDelegate.java:835: error: cannot find symbol
: m_activity.getDisplay().getRefreshRate();
^
symbol: method getDisplay()
location: variable m_activity of type Activity
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/QtLayout.java:95: error: cannot find symbol
Display display = (Build.VERSION.SDK_INT < Build.VERSION_CODES.R)
^
symbol: variable R
location: class VERSION_CODES
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/QtLayout.java:97: error: cannot find symbol
: ((Activity)getContext()).getDisplay();
^
symbol: method getDisplay()
location: class Activity
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/ExtractStyle.java:418: error: cannot find symbol
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.Q)
^
symbol: variable Q
location: class VERSION_CODES
/home/hebasto/git/gui/src/qt/android/src/org/qtproject/qt5/android/ExtractStyle.java:421: error: cannot find symbol
numStates = stateList.getStateCount();
^
symbol: method getStateCount()
location: variable stateList of type StateListDrawable
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
8 errors
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.6.1/userguide/command_line_interface.html#sec:command_line_warnings
BUILD FAILED in 827ms
...
Fixing it by updating the Gradle tool's properties.
