internalFindViewById raises "unchecked cast" warning

[ened]

Starting from recent appcompat library versions (I'm not sure which one exactly), the need to cast the result of findViewById seem to have gone away. In fact, if the casting in current form stays, then compiling with "-Xlint:unchecked" will raise warnings like this:

  required: T
  found:    View
  where T is a type-variable:
    T extends View declared in method <T>internalFindViewById(int)
/git/project/app/src/main/java/SomeActivity_.java:40: warning: [unchecked] unchecked cast
        return ((T) this.findViewById(id));

AndroidAnnotations version: 4.4.0
Android compile SDK version: 26

Annotated code:

@EActivity
public class SomeActivity extends AppCompatActivity {
}

Expected generated code:

@Override
public<T extends View> T internalFindViewById(int id) {
    return this.findViewById(id);
}

Actual generated code:

@Override
public<T extends View> T internalFindViewById(int id) {
    return ((T) this.findViewById(id));
}

This would probably require different style of code generation depending on the activities parent class (AppCompatActivity, Activity) and if the findViewById call supports the casting already.

[dodgex]

@WonderCsabo think we should simply put a @SuppressWarning on the generated method. What do you think?

[WonderCsabo]

That was the most easiest, however we could add unnecessary annotations that way. I already thought about this, I will try to hack around something.

…

On Dec 1, 2017 08:14, "Kay-Uwe Janssen" ***@***.***> wrote: @WonderCsabo <https://github.com/wondercsabo> think we should simply put a @SuppressWarning on the generated method. What do you think? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#2090 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAdU5SnWHEEXv4zhbxYN1R-0Iv4EjciJks5s76dNgaJpZM4QwDPC> .

[dodgex]

okay, have fun. :)

[dodgex]

Not sure, but maybe we could just remove the cast for appcompat. iirc the cast is only there as appcompat required it when we implemented the internalFindViewById stuff.

[WonderCsabo]

This is a little bit more complex. Actually, this was introduced by Android Oreo. Since that version, the actual android.app.Activity has generic return type for findViewById(). AppCompatActivity also declares this method, to make this available on Android < Oreo . However if the user does not use appcompat and the compileSdkVersion is < Oreo, he only sees the old findViewById(). We declare findViewById() in HasViews, and simply it was implemented by Activity, Fragment, ViewGroup etc. But now this is not the case, because they changed the return type. This is why we introduced a new method and always implement it. See #2001 #2008.

One fix would be check if the parent class has generic findViewById(), and if so, do not add the cast. I would like to implement this first.

I am still thinking about if this possible to get rid of the generated internalFindViewById() method completely, because it is totally unnecessary with appcompat or compileSdkVersion >= Oreo.