How to get Executor for main thread on API level < 28
You can use (in activity for example):
ContextCompat.getMainExecutor(this);
You can use code snippet from retrofit https://github.com/square/retrofit/blob/master/retrofit/src/main/java/retrofit2/Platform.java
public class MainThreadExecutor implements Executor { private final Handler handler = new Handler(Looper.getMainLooper()); @Override public void execute(Runnable r) { handler.post(r); }}
You can use new HandlerExecutor(Looper.getMainLooper()); from com.google.android.gms.common.util.concurrent.HandlerExecutor...in the end it's the same answer as atarasenko.
I added an extension in Kotlin for that:
fun Context.mainExecutor(): Executor { return if (VERSION.SDK_INT >= VERSION_CODES.P) { mainExecutor } else { HandlerExecutor(mainLooper) }}