Change AppBar's icons depending on the Context (Fragments)

Question

I have my AppBar on my MainActivity. My MainActivity has a layout which works like a container of fragments.

What I want to accomplish is that I want my AppBar icons to change depending on which Fragment's on top at the moment.

something like this:

switch (item.getItemId()){
    case R.id.semanario:
        fragmentTransaction.replace(R.id.viewPagerMainContenedor, new FragmentSemanario());
        fragmentTransaction.addToBackStack(null).commit();
        myToolbar.SETICON(R.drawable.iconExample) (And how to change the xml atributte "app:showAsAction = always)
        break;

I thought about making an AppBar for each fragment but it should be easier than that, isn't it?

Answer 1

Add a method inside your main activity something like below :

updateToolbar(int title, int drawable){
 toolbar.setTitle(title);
 toolbar.setIcon(drawable);
}

and then call this method from your fragment :

getActivity().updateToolbar(title,R.drawable.icon);

To change action overflow icon :

<style name="AppTheme.Base" parent="Theme.AppCompat.Light">
<item name="actionOverflowButtonStyle">@style/OverFlow</item>
</style>

<style name="OverFlow" 
parent="Widget.AppCompat.ActionButton.Overflow">
<item name="android:src">@drawable/my_overflow_menu</item>
</style>

For other custom icons you can simply update through thier views. Hope it helps.