The following method I wrote, which works fine, is in my Utils package and I call it from some of my activities.
private static Date date = null;
public static Date getCurrentTime(final Context context){
FirebaseFunctions firebaseFunctions;
firebaseFunctions = FirebaseFunctions.getInstance();
firebaseFunctions.getHttpsCallable("currentTime").call()
.addOnCompleteListener(new OnCompleteListener<HttpsCallableResult>() {
@Override
public void onComplete(@NonNull Task<HttpsCallableResult> task) {
try{
String dateString = task.getResult().getData().toString();
System.out.println("555555555555 TIME : " + dateString);
date = new Date(Long.getLong(dateString));
}
catch(Exception e){
convertFirebaseExceptionToAlertDialog(context, "A network error");
}
}
});
while (date == null){
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return date;
}
I want to know if there are better ways than checking the value by a loop to return a value from methods like this. (Methods that get the value will be returned from inner methods like onComplete, onSuccess)
You can make something that is asynchronous work synchronously. For your code that means that your getCurrentTime can't return a Date. The code that calls getCurrentTime, will always need to be aware that it's calling a function that returns an asynchronous result.
The simplest way I usually deal with this is by defining a custom callback interface for the type:
public interface DateCallback {
void onCallback(Date value);
}
Then you can pass a callback into getCurrentTime, which its implementation then calls when it got the current time from Cloud Functions. Something like:
public static Date getCurrentTime(final Context context, DateCallback callback){
FirebaseFunctions firebaseFunctions;
firebaseFunctions = FirebaseFunctions.getInstance();
firebaseFunctions.getHttpsCallable("currentTime").call()
.addOnCompleteListener(new OnCompleteListener<HttpsCallableResult>() {
@Override
public void onComplete(@NonNull Task<HttpsCallableResult> task) {
try{
String dateString = task.getResult().getData().toString();
System.out.println("555555555555 TIME : " + dateString);
callback.onCallback(new Date(Long.getLong(dateString)));
}
catch(Exception e){
convertFirebaseExceptionToAlertDialog(context, "A network error");
}
}
});
}
And then you'd call it with:
getCurrentTime(this, new DateCallback() {
public void onCallback(Date value) {
System.out.println("Current time "+value)
}
});
Also see: