Android app - Back button

Question

I want to display a back button in the left corner of the action bar and I do not completely know where to make the change in the activity.java to make it visible and functional.

@Override
    protected void onCreate(Bundle savedInstancesState){
        super.onCreate(savedInstancesState);
        setContentView(R.layout.activity_news);
        ActionBar actionBar = getSupportActionBar();
        actionBar.setIcon(R.mipmap.ic_launcher);

This is what I want to display. View Image

`actionbar.setHomeButtonEnabled`, though you should be using the toolbar instead of the old actionbar — tyczj, May 17 '16 at 19:13
I'm getting an error in the code. It's written in red text. I think your code is wrong and I maybe wrong about that but do you have a different solution to this? Thanks in advance! — Joe Stephan, May 17 '16 at 19:15
It's showing an error and suggested to rename the reference. — Joe Stephan, May 17 '16 at 19:21
well you reference is `actionBar` hopefully you didnt just copy and past exactly what I wrote — tyczj, May 17 '16 at 19:24
Well, I did not just copy and paste your code. Although I implemented it in the activity and it displayed an error. I really appreciate you taking the time to solve my post. — Joe Stephan, May 17 '16 at 19:25
tyczj you somewhat solved my question but @ShadabAnsari fully solved it — Joe Stephan, May 17 '16 at 19:30
The problem is that it's not functional. It doesn't go back to the previous activity. — Joe Stephan, May 17 '16 at 19:31
Possible duplicate of [Display Back Arrow on Toolbar Android](http://stackoverflow.com/questions/26651602/display-back-arrow-on-toolbar-android) — Vucko, May 17 '16 at 20:57

score 1 · Accepted Answer · answered May 17 '16 at 19:33

1

you have to enable it by doing

actionBar.setDisplayHomeAsUpEnabled(true);

then if you want it to do something you need to look for the click in the onOptionsItemSelected

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()){
        case android.R.id.home:
            //do something here
            break;
        default:
            break;
    }

answered May 17 '16 at 19:33

tyczj

71,600
54
194
296

Thank you very much for your answer. It worked perfectly. – Joe Stephan May 19 '16 at 07:56

score 1 · Answer 2 · answered May 17 '16 at 20:52

Showing it is as simple as putting this under your onCreate method in your Activity:

getSupportActionBar().setDisplayHomeAsUpEnabled(true);

Then to control that input put this in your Activity:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        // Respond to the action bar's Up/Home button
        case android.R.id.home:
            //or do what you want
            finish();
            break;
        default:
            break;
    }
    return super.onOptionsItemSelected(item);
}

score 0 · Answer 3 · answered May 17 '16 at 20:21

// activity

    mToolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(mToolbar);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

// fragments

    mToolbar = (Toolbar) view.findViewById(R.id.toolbar);

    ((AppCompatActivity)getActivity()).setSupportActionBar(mToolbar);
    ((AppCompatActivity)getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);

It may helps some one

Android app - Back button

3 Answers3