[android] Use ALooper_addFd() and callbacks to wake up

This is needed for plugging into an existing Looper because
we won't call ::run() on the main thread (this is called
on the Java side of the application automatically by Android).

But we still need to wake up and process the events. For that
we create a pipe and write to the pipe to wake up the main
loop and we process events on the callback of the fd handler.

Fixes #4682

1 files changed, 7 insertions, 0 deletions

diff --git a/platform/android/src/run_loop_impl.hpp b/platform/android/src/run_loop_impl.hpp
index 2dd912994f..5cf7231175 100644
--- a/platform/android/src/run_loop_impl.hpp
+++ b/platform/android/src/run_loop_impl.hpp
@@ -27,6 +27,11 @@ public:
         std::list<Runnable*>::iterator iter;
     };
 
+    Impl(RunLoop*, RunLoop::Type);
+    ~Impl();
+
+    void wake();
+
     void addRunnable(Runnable*);
     void removeRunnable(Runnable*);
     void initRunnable(Runnable*);
@@ -36,6 +41,8 @@ public:
 private:
     friend RunLoop;
 
+    int fds[2];
+
     JNIEnv *env = nullptr;
     bool detach = false;