Back Button in ActionBar of App

Question

Generally switching from one activity to another activity hamburger icon is replaced with back arrow. I want to control the functionality of that arrow. I have seen many contents here but most of them were related to hardware's back button. How can I control that?

I am trying the functionality in case of fragments. Also I have Navigation drawer attached with the hamburger icon.

I tried this-

if(id == android.R.id.home){
        getSupportFragmentManager().beginTransaction().replace(R.id.main_container, new AmbulanceMap()).commit();
        getSupportActionBar().setTitle("Book A Ride");
        getSupportActionBar().setDisplayHomeAsUpEnabled(false);
    }

but doesnt work as I hoped.

I want my back button to change the fragmentto previous fragment.

when you create onCreateOption menu and its itemselected ....u can use android.R.id.home id for controlling that back button. — Sahil, Sep 03 '17 at 14:52
I tried that but it is not working it just open the drawer attached. — Shubham Agarwal Bhewanewala, Sep 03 '17 at 14:55
did you add getSupportToolbar().setDisplayHomeUpAsEnabled(true); — Sahil, Sep 03 '17 at 14:59
yes i did that.. everything is working well and good except the back button — Shubham Agarwal Bhewanewala, Sep 03 '17 at 15:02
I want my back button to change the fragmentto previous fragment. — Shubham Agarwal Bhewanewala, Sep 03 '17 at 15:06
you can do that with saving your fragment in stack ...thats what i think can work. addToBackstack....try it ...nd pass the fragment name in its paramater...it should work — Sahil, Sep 03 '17 at 15:08
try this ....maybe it can help ..my previous answer meant this ....https://stackoverflow.com/questions/18305945/how-to-resume-fragment-from-backstack-if-exists — Sahil, Sep 03 '17 at 15:11
Sahil tried that too.. but result didnt change.. but will try it once again — Shubham Agarwal Bhewanewala, Sep 03 '17 at 15:13

Valentun · Accepted Answer · 2017-09-03T16:11:28.427

1

I had the same problem once. Just like you, things like checking if Android.R.id.home is clicked didn't work. But I solved it using that:

Set navigation listener to toolbar:

toolbar.setToolbarNavigationClickListener(v -> onBackPressed());

If it should be within fragment:

Create an public method in activity.
In fragment's onAttach (or later) cast getActivity() to your activity and call method you was defined previously.

Example:

// YourActivity
public void setHomeListener(OnLickListener listener){
    toolbar.setToolbarNavigationClickListener(listener);
}

//Fragment's onCreate
((YourActivity)getActivity()).setHomeListener(v -> onBackPressed());

//Fragment's onDestroy
 ((YourActivity)getActivity()).setHomeListener(null);

And, of course, set home us up enabled to show back arrow.

EDIT

if you don't use labmdas u should use:

(YourActivity)getActivity()).setHomeListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        YourFragment.this.onBackPressed();
    }
});

edited Sep 03 '17 at 16:11

answered Sep 03 '17 at 15:14

Valentun

1,661
12
23

@ShubhamAgarwalBhewanewala which code do you exaclty need? – Valentun Sep 03 '17 at 15:31
setting up navigationClick listener – Shubham Agarwal Bhewanewala Sep 03 '17 at 15:32
@ShubhamAgarwalBhewanewala, what is unclear? May be where you can find drawer Toggle? – Valentun Sep 03 '17 at 15:35
when i am setting up listener it is giving me to add On click listener only – Shubham Agarwal Bhewanewala Sep 03 '17 at 15:36
@ShubhamAgarwalBhewanewala do you sure you set listener to instance of ActionBarDrawerToggle? Because it has this method. – Valentun Sep 03 '17 at 15:39
yes. i said i found that listener which you mention but int the bracket u wrote v -> onBackPressed() , this i dint get – Shubham Agarwal Bhewanewala Sep 03 '17 at 15:42
@ShubhamAgarwalBhewanewala oh, sorry its lambdas, just wait a bit. – Valentun Sep 03 '17 at 15:43
@ShubhamAgarwalBhewanewala no effect means onClick do not called? – Valentun Sep 03 '17 at 15:53
I mean to say that what we intend to do doesnot happen. instead drawer opens. – Shubham Agarwal Bhewanewala Sep 03 '17 at 15:55
@ShubhamAgarwalBhewanewala I've mistaken a bit, you should set listener to toolbar, not toggle. And, its better to call fragmentManager.popBackStack()(instead of onBackPressed()) – Valentun Sep 03 '17 at 16:05
Thanx for helping.. pls change the toggle to toolbar in solution – Shubham Agarwal Bhewanewala Sep 03 '17 at 16:09

hacksy · Answer 2 · 2017-09-03T15:12:20.880

0

The back button of the ActionBar is a menuItem so you need to override onOptionsItemSelected like this:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()){
        case android.R.id.home:
            //Your back button logic here
            break;
    }
    return true;
}

Also don´t forget to add getSupportActionBar().setDisplayHomeAsUpEnabled(true); after setting the Toolbar

edited Sep 03 '17 at 15:12

answered Sep 03 '17 at 14:54

hacksy

830
5
14

I tried that but it is not working it just open the drawer attached. – Shubham Agarwal Bhewanewala Sep 03 '17 at 14:55
can you copy the code of your Activity that contains that Toolbar? – hacksy Sep 03 '17 at 15:01
I dint get you. what actually you want to see? I can post. – Shubham Agarwal Bhewanewala Sep 03 '17 at 15:07
I want to take a look at the code of your Activity . – hacksy Sep 03 '17 at 15:10

Back Button in ActionBar of App

2 Answers2