how to back to previous fragment on pressing manually back button

Question

I have one activity and multiple fragments in my app. i want to back one by one fragments when pressing back button which in all fragments.

i used this code segment but when pressing back button it comes to main activity without back one by one. Also i want to change the icon when it's comes to the main activity.(msg_alert)

 btnBack.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            FragmentManager fm = MainActivity.this
                    .getSupportFragmentManager();
            FragmentTransaction ft = fm.beginTransaction();
            Fragment fragment = new MainMenuLayout();
            ft.replace(R.id.activity_main_content_fragment, fragment);
            ft.commit();
            btnBack.setVisibility(View.VISIBLE);
            btnBack.setImageResource(R.drawable.msg_alert);
            tvTitle.setText("Layout 0");

        }
    });

Check out BaseContainerFragment.java class in this reference .. It does all you need.http://stackoverflow.com/questions/18120510/dynamically-changing-the-fragments-inside-a-fragment-tab-host/19859871#19859871 — AndroidHacker, Aug 01 '14 at 06:15
you should look at [this](http://developer.android.com/training/implementing-navigation/temporal.html#back-fragments) — vijay_t, Aug 01 '14 at 06:24
i go through these articles but still i don't no how to do this. i have many fragments in this app. — user3800832, Aug 01 '14 at 06:54

score 2 · Answer 1 · answered Aug 01 '14 at 06:46

Lets say you are having two fragments A and B. Fragment A is is attached at the startup of activity and on any user event you navigate to fragment B by replacing the Fragment A.

1) while adding Fragment B to the activity

// Works with either the framework FragmentManager or the
// support package FragmentManager (getSupportFragmentManager).
getSupportFragmentManager().beginTransaction()
                           .replace(R.id.container, fragmentB, "detail")
                           // Add this transaction to the back stack
                           .addToBackStack()
                           .commit();

2) override the onBackPressed of the activity to handle the back button press event.

@override
public void onBackPressed() {
     // is there any fragment in backstack, if yes popout.
    if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
        getSupportFragmentManager().popBackStack();
        return;
    }
    super.onBackPressed();
}

@user3800832 as many times you call addToBackStack() in a fragmentTransaction, it will push to replaced fragement to backstack. And calling getSupportFragmentManager().popBackStack() will pop the top fragment from the backstack You can find sample code in API demos at path: \samples\ApiDemos\src\com\example\android\apis\app\FragmentStack.java — vijay_t, Aug 01 '14 at 07:12

Pravin · Answer 2 · 2014-08-01T06:29:10.413

I seen in your code that you are only replace the content frame. and so the result is backpress it comes to activity.
Also be sure that you have your mannual back button in the activity
this is test xml for activity

<?xml version="1.0" encoding="utf-8"?>

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Back" />

<FrameLayout
    android:id="@+id/activity_main_content_fragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
</FrameLayout>

Use

Fragment fragment = new MainMenuLayout();
                    ft.replace(R.id.activity_main_content_fragment, fragment);
                    ft.addToBackStack(null);// TODO parameter here it tag of fragment or null or "" String
                    ft.commit();

For more information about fragments backstack go through this android developer refrence :-Fragment BackStack

score 0 · Answer 3 · answered Aug 01 '14 at 06:21

this is one more option ,

in the Activity.

Fragment secondfragment= new SecondFragmnet();

 @Override
public void onBackPressed() {

     if(secondfragment.isVisible()){
    // replace 1st fragment
      }else{
         // Alert dialog for Exit App
     }
// you can check multiple fragments.

Hope it helps you

score 0 · Answer 4 · answered Aug 01 '14 at 06:26

0

You have to Use addToBackStack() method while doing Transaction Between Fragments...

Read This : Implement Back Navigation for Fragments

Use Following code when you use Fragment Transaction...

String backStateName = fragment.getClass().getName(); // getting Fragment Name..
FragmentManager fragmentManager = getFragmentManager();
    fragmentManager.beginTransaction().replace(R.id.content_frame, fragment)
    .addToBackStack(backStateName) //adding it to BackStack..
    .commit();

answered Aug 01 '14 at 06:26

Pragnesh Ghoda シ

8,318
3
25
40

how to pass fragments , because error showing the underlining the fragment – user3800832 Aug 01 '14 at 07:04
write this code when you are selecting fragment..means in Activity where you are handling transaction of fragment.. – Pragnesh Ghoda シ Aug 01 '14 at 08:11

score 0 · Answer 5 · answered Aug 01 '14 at 06:29

0

In Fragments we dont have back navigation..

We can acheive that through replace() method.

answered Aug 01 '14 at 06:29

user2047685

1

how to back to previous fragment on pressing manually back button

5 Answers5