setSupportActionBar (androidx.appcompat.widget.Toolbar) in AppCompatActivity cannot be applied

Question

An error showing incompatible types Android widget toolbar cannot be converted in Java compiler while working on Android Studio.

    Toolbar toolbar = (Toolb         


        

Answer 1

You can invoke ActivityCompat#requireViewById which allows to omit the type cast and returns a @NonNull Toolbar reference:

Toolbar toolbar = ActivityCompat.requireViewById(this, R.id.toolbar);
setSupportActionBar(toolbar);

The title can be set on the @Nullable ActionBar reference returned by AppCompatActivity#getSupportActionBar:

ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
    actionBar.setTitle("GPS PRESENCE SYSTEM");
}

Answer 2

You are using androidx and Android both at the same time. That is throwing an error. Either use androidx or use android appcompat.