When I press the back button of my phone the app closes

Question

I have made an app with many activities and I have included a bottom navigation bar to all of them. I used finish(); after any intent not to get any memory leak problem but when I press the back button of my phone the app closes. What should I do?

//an  intent of my app 


        Button btnsuita = (Button) findViewById(R.id.souita_btn);
        btnsuita.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent intent = new Intent(HotelRooms.this, HotelRoomsSouita.class);
                startActivity(intent);
                finish();

            }
        });



  //An Example of Bottom Navigation Bar
        BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.BottomNavView_bar);
        BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
        Menu menu = bottomNavigationView.getMenu();
        android.view.MenuItem menuItem = menu.getItem(0);
        menuItem.setChecked(true);

        bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                switch (item.getItemId()) {

                    case R.id.ic_home:
                        Intent intent1 = new Intent(HotelRoomsSouita.this, MainMenu.class);
                        startActivity(intent1);
                        finish();
                        break;

                    case R.id.ic_back:
                        Intent intent2 = new Intent(HotelRoomsSouita.this, HotelRooms.class);
                        startActivity(intent2);
                        finish();
                        break;

                    case R.id.ic_contact_us:
                        Intent intent3 = new Intent(HotelRoomsSouita.this, Mail.class);
                        startActivity(intent3);
                        finish();
                        break;
                }


                return false;
            }

        });

It's because you're finishing every activity even though you probably don't want to — EpicPandaForce, Apr 23 '19 at 20:53
I want to close them ,but I want also to go on the previous Activity when the back is pressed — Jordan Kotiadis, Apr 23 '19 at 20:58
By closing you mean crashing? If yes please update your post with the related logs. — Kwnstantinos Nikoloutsos, Apr 23 '19 at 20:59
You cannot. Once the (prev) activity is destroyed, you cannot go to previous activity(from new activity) when back is pressed. If you really want this way, launch a new intent when back button is pressed. — dcanh121, Apr 23 '19 at 21:05
(or just use Fragments, that's kinda what they're for... among other things) — EpicPandaForce, Apr 23 '19 at 22:51

dcanh121 · Accepted Answer · 2019-04-23T20:54:31.903

0

Remove finish() in the switch every case.

If you want to ignore back button clicks, then you can add this code in the activity.

@Override
public void onBackPressed() {
   //Do anything if you wish
}

edited Apr 23 '19 at 20:54

answered Apr 23 '19 at 20:37

dcanh121

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score 0 · Answer 2 · answered Apr 23 '19 at 20:50

Since you are finishing every activity ,there is o activity remain in the backstack or background . so the application closes.

You can use view pager to inflate fragment for bottom navigation view . This is the correct approach by google material design guid lines.

Never use activity for bottom navigation view .

And still if you continue with your activity , then override the onBackpress method of the activtiy .

Kwnstantinos Nikoloutsos · Answer 3 · 2019-04-23T21:36:40.013

If I understand your problem correctly you want the user to be able to go back in previous activities while your application does not cause any memory leaks(by starting same activity again and again)

Solution:

Remove finish() from each case in onNavigationItemSelected
Go to your manifest file and add android:launchMode="singleInstance" to each Activity
Ovveride onBackPressed so that it does nothing in your first-started activity as dcanh121 said.

If you do that then if user tries to open the same Activity which was already opened before, it will cause the app to open the previous activity instead of creating a new one.. (read more about this)

Therefore you won't have any memory leak problems :)

When I press the back button of my phone the app closes

3 Answers3