i have a simple method that takes a generic List parameter but for some reason my IDE(Eclipse) states how it cannot be resolved?
Am i doing something wrong here
private OnClickListener removeFieldListener(final LinearLayout layout,
List<T> viewList) {
return new OnClickListener() {
@Override
public void onClick(View v) {
int indexToDelete = layout.indexOfChild(v);
}
};
}
In that case, the T parameter has to be defined somewhere. As I guess your class does not declares this parameter, you have to put it in your method declaration, like
private <T> OnClickListener removeFieldListener(final LinearLayout layout,
List<T> viewList) {
But this will only move the problem to the caller of this method ...
T is based on the type of the list being passed in. So there shouldn't be any additional burden on callers, compared to using a wildcard or the raw type.
<T> that's the second part of the signature. This means that the method is parameterised without you needing to add a generic parameter to the class. See the Generic Methods section of the generics FAQ.
Riduidel is right in that the problem is that you haven't declared the T anywhere.
Depending on what you want to do with the contents of the list, chances are you can just use a wildcard. List<?> viewList would work if you're only pulling Objects out of it; or List<? extends IListener> will allow you to get IListeners out of it, etc.
In general, you don't need a generic parameter if it only appears once within your method, and you should use a wildcard instead. If it does appear multiple times, for example you remove things from the list and assign them to variables of type T, then you do indeed need the wildcard and you should parameterise your method as Riduidel suggests.
