java/processing return ArrayList throws: This method must return a result of Type ArrayList

Question

I have this function makeAirportManagers() which should return an ArrayList <MarkerManager> all required variables map, countryMarkers and airportMarkers are global (dirty processing style).

ArrayList  makeAirportManagers(){
  ArrayList  managers = new ArrayList();
  for (Marker country : countryMarkers){
    MarkerManager currentMarkerManager = new MarkerManager();
    for (Marker airport : airportMarkers){
      Location airportLocation = airport.getLocation();
      ScreenPosition airportScreenPos = map.getScreenPosition(airportLocation);
      if(country.isInside(map, airportScreenPos.x, airportScreenPos.y)){
        currentMarkerManager.addMarker(airport);
      }
    }
    currentMarkerManager.disableDrawing();
    managers.add(currentMarkerManager);
    map.addMarkerManager(currentMarkerManager);
    airportManagersBuild = true;
    return managers;
  }
}

The console prints: This method must return a result of Type ArrayList

And really I don't no why!

In another version of the code, I count the items of managersto make sure it`s not empty and it gets 178 items like expected.

I am using Processing 1.5.1 because of the Unfolding library I'm playing with.

Dan D. · Accepted Answer · 2012-11-06 13:44:39Z

3

Your return method is inside the for loop. You must move it one line below.

answered Nov 6, 2012 at 13:44

Dan D.

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1 Comment

PDXIII Over a year ago

I am so blind! Thank you very much!

Jerome · Accepted Answer · 2012-11-06 13:50:45Z

1

If countryMarkers has no element in it, you will never reach the line return managers and your method won't return anything.

Even if you know that your container will never be empty, the Java compiler does not. Thus your error.

edited Nov 6, 2012 at 13:50

answered Nov 6, 2012 at 13:45

Jerome

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2 Comments

PDXIII Over a year ago

Thank you, but countryMarkers is not empty.

Jerome Over a year ago

You know that. Not your compiler. Your compiler is righter than you or me

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