Toolbar - Switching from drawer to back button with only one Activity

Question

I\'ve been searching for a while on how to change between the drawer open/close icon (going from a hamburger to the arrow) to a simple back arrow. My application at the mome

Answer 1

//This if block makes the menu back button to respond to clicks
    //The onOptionsItemSelected fun for whatever reason was not capturing back menu clicks
    if (toolbar != null) {
       /* toggle = ActionBarDrawerToggle(
                this, drawer_layout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close)
        toggle.syncState()
        drawer_layout.setDrawerListener(toggle)*/
        supportFragmentManager.addOnBackStackChangedListener(object : FragmentManager.OnBackStackChangedListener {
            override fun onBackStackChanged() {
                if (supportFragmentManager.backStackEntryCount > 0) {
                    supportActionBar?.setDisplayHomeAsUpEnabled(true) // show back button
                    toolbar.setNavigationOnClickListener(object : View.OnClickListener {
                        override fun onClick(v: View) {
                            onBackPressed()
                        }
                    })
                } else {
                    //show hamburger
                    supportActionBar?.setDisplayHomeAsUpEnabled(false)
                    toggle.syncState()
                    toolbar.setNavigationOnClickListener(object : View.OnClickListener {
                        override fun onClick(v: View) {
                            drawer_layout.openDrawer(GravityCompat.START)
                        }
                    })
                }
            }
        })

    }

You need to comment out "toggle = ActionBarDrawerToggle( this, drawer_layout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close) toggle.syncState() drawer_layout.setDrawerListener(toggle)" (4-7 lines) if you are using the auto generated Navigation layout in Android Studio, else the behavior of the back menu button will be erratic. That is what i did and it worked perfectly for me. Hope this helps someone