I have an application with several Activities in Android and I want the user to be able to log-out by pressing a menu button. The problem I have is that

A) Android doesn&#39;t let you terminate the application and  
B) even when I send the user to the `LoginActivity` again they can always press *back* and get right back to the previous activity they were in.

I already tried to launch the Activity with the two following flags: 

    Intent intent  = new Intent(this, LoginActivity.class);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);    	
    startActivity(intent);

I also tried with each one of them by themselves.

I also tried calling `finish()` after `startActivity(intent)` as I read in another StackOverflow
question.

How to clear the Android Stack of activities?

I&#39;m working on an application in which tabs are implemented using `FragmentActivity`. Since, tabs are required throughout the application, fragments are used extensively to make the application compatible on all the versions of android.

 As a consequence, I&#39;m facing a problem in visualizing as to what fragments are present on the backstack. I&#39;m sure there is a **way to retrieve the list of fragments present on the backstack**. Thanks.

How to get a list of backstack fragment entries in android?

I have an Activity in which I go through several fragments. In every fragment I have several views (`EditText, ListView, Map`, etc).

How can I save the instance of the fragment that is shown at that moment? I need it to work when the activity is `onPause() --&gt; onResume()`. Also I need it to work when I return from another fragment (pop from backstack).

From the main `Activity` I call the first fragment, then from the the fragment I call the next one.

Code for my Activity:

    public class Activity_Main extends FragmentActivity{

    public static Fragment_1 fragment_1;
    public static Fragment_2 fragment_2;
    public static Fragment_3 fragment_3;
    public static FragmentManager fragmentManager;

    @Override
     protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

         fragment_1 = new Fragment_1();

         fragment_2 = new Fragment_2();

         fragment_3 = new Fragment_3();

         fragmentManager = getSupportFragmentManager();
	     FragmentTransaction transaction_1 = fragmentManager.beginTransaction();
	     transaction_1.replace(R.id.content_frame, fragment_1);
	     transaction_1.commit();
    }}

Then here is the code for one of my fragments:

    public class Fragment_1 extends Fragment {

          private EditText title;
          private Button go_next;
  
 
          @Override
          public View onCreateView(final LayoutInflater inflater,
			ViewGroup container, Bundle savedInstanceState) {

		        View rootView = inflater.inflate(R.layout.fragment_1,
				container, false);

                title = (EditText) rootView.findViewById(R.id.title);

                go_next = (Button) rootView.findViewById(R.id.go_next);

                image.setOnClickListener(new View.OnClickListener() {

		     @Override
		     public void onClick(View v) {

                     FragmentTransaction transaction_2 = Activity_Main.fragmentManager
					.beginTransaction();
			
		    	     transaction_2.replace(R.id.content_frame,
					  Activity_Main.fragment_2);
		    	     transaction_2.addToBackStack(null);
		     	     transaction_2.commit();  
                   
                });
            }}

I have searched a lot of information but nothing clear. Can somebody give a clear solution and an example, please ? 

Android - save/restore fragment state

Say I have an activity that has fragments added programmatically:

    private void animateToFragment(Fragment newFragment, String tag) {
        FragmentTransaction ft = getFragmentManager().beginTransaction();
        ft.replace(R.id.fragment_container, newFragment, tag);
        ft.addToBackStack(null);
        ft.commit();
    }

What is the best way to return to the previous fragment that was visible?

I found https://stackoverflow.com/questions/4649508/back-functionality-on-button-click-in-android but I&#39;m thinking simulating a back key event isn&#39;t the right way to go about it (and I can&#39;t get it to work either):


    dispatchKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_BACK));

Calling `finish()` just closes the activity which I&#39;m not interested in.

Is there a better way to go about this?

Programmatically go back to the previous fragment in the backstack

When the BACK button is pressed on the phone, I want to prevent a specific activity from returning to its previous one.

Specifically, I have login and sign up screens, both start a new activity called `HomeScreen` when successful login/signup occurs. Once HomeScreen is started, I want to prevent the users from being able to return to the login or sign up screens by pressing the BACK key. 

I tried using `Intent.FLAG_ACTIVITY_NO_HISTORY`, but since the application has Facebook integration, when the &#39;Login with Facebook&#39; is used, Facebook should return to the initial login screen, therefore I should keep a history of these activities.

I thought of overriding the behaviour of the BACK button on `HomeScreen` to directly finish an application when the button is pressed and I used

    @Override
	public void onBackPressed() {
		finish();
	}

but that also does not work.


How to prevent going back to the previous activity?

I have multiple fragment inside an activity. On a button click I am starting a new fragment, adding it to backstack. I naturally expected the `onPause()` method of current Fragment and `onResume()` of new Fragment to be called. Well it is not happening.

&lt;h2&gt;LoginFragment.java&lt;/h2&gt;
    public class LoginFragment extends Fragment{
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
          final View view  =   inflater.inflate(R.layout.login_fragment, container, false);
          final FragmentManager mFragmentmanager =  getFragmentManager();
          
          Button btnHome  =	(Button)view.findViewById(R.id.home_btn);
          btnHome.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view){
               HomeFragment	fragment	= new HomeFragment();
               FragmentTransaction ft2   =  mFragmentmanager.beginTransaction();
               ft2.setCustomAnimations(R.anim.slide_right, R.anim.slide_out_left
                        , R.anim.slide_left, R.anim.slide_out_right);
               ft2.replace(R.id.middle_fragment, fragment);
               ft2.addToBackStack(&quot;&quot;); 
               ft2.commit(); 	
             }
          });
      }

      @Override
      public void onResume() {
         Log.e(&quot;DEBUG&quot;, &quot;onResume of LoginFragment&quot;);
         super.onResume();
      }
        
      @Override
      public void onPause() {
        Log.e(&quot;DEBUG&quot;, &quot;OnPause of loginFragment&quot;);
        super.onPause();
      }
    }

&lt;h2&gt;HomeFragment.java&lt;/h2&gt;

    public class HomeFragment extends Fragment{
      @Override
      public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         final View view  =   inflater.inflate(R.layout.login_fragment, container, false);
      }
    
      @Override
      public void onResume() {
         Log.e(&quot;DEBUG&quot;, &quot;onResume of HomeFragment&quot;);
         super.onResume();
      }
            
      @Override
      public void onPause() {
         Log.e(&quot;DEBUG&quot;, &quot;OnPause of HomeFragment&quot;);
         super.onPause();
      }
    }

What I expected, was,

 1. When button is clicked, **LoginFragment** gets replaced with
    **HomeFragment**, `onPause()` of **LoginFragment**, and `onResume()` of
    **HomeFragment** gets called
 2. When back is pressed, **HomeFragment** is poped out and **LoginFragment** is
    seen, and `onPause()` of **HomeFragment** and `onResume()` of **LoginFragment**
    gets called.


What I am getting is,

 1. When button is clicked, **HomeFragment** is correctly replacing
    **LoginFragment**, onResume() of **HomeFragment** is called, but onPause()
    of **LoginFragment** is never called.
 2. When back pressed, **HomeFragment** is correctly popping to reveal
    **LoginFragment**, onPause() of **HomeFragment** gets called, but onResume()
    of **LoginFragment** never gets called.

Is this the normal behaviour? Why is `onResume()` of **LoginFragment** not getting called when I press the back button.

Fragment onResume() &amp; onPause() is not called on backstack

I&#39;ve written up a dummy activity that switches between two fragments.  When you go from FragmentA to FragmentB, FragmentA gets added to the back stack.  However, when I return to FragmentA (by pressing back), a totally new FragmentA is created and the state it was in is lost.  I get the feeling I&#39;m after the same thing as [this][1] question, but I&#39;ve included a complete code sample to help root out the issue: 

    public class FooActivity extends Activity {
      @Override public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(android.R.id.content, new FragmentA());
        transaction.commit();
      }
    
      public void nextFragment() {
        final FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(android.R.id.content, new FragmentB());
        transaction.addToBackStack(null);
        transaction.commit();
      }
    
      public static class FragmentA extends Fragment {
        @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
          final View main = inflater.inflate(R.layout.main, container, false);
          main.findViewById(R.id.next_fragment_button).setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
              ((FooActivity) getActivity()).nextFragment();
            }
          });
          return main;
        }
    
        @Override public void onSaveInstanceState(Bundle outState) {
          super.onSaveInstanceState(outState);
          // Save some state!
        }
      }
    
      public static class FragmentB extends Fragment {
        @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
          return inflater.inflate(R.layout.b, container, false);
        }
      }
    }

With some log messages added:

    07-05 14:28:59.722 D/OMG     ( 1260): FooActivity.onCreate
    07-05 14:28:59.742 D/OMG     ( 1260): FragmentA.onCreateView
    07-05 14:28:59.742 D/OMG     ( 1260): FooActivity.onResume
    &lt;Tap Button on FragmentA&gt;
    07-05 14:29:12.842 D/OMG     ( 1260): FooActivity.nextFragment
    07-05 14:29:12.852 D/OMG     ( 1260): FragmentB.onCreateView
    &lt;Tap &#39;Back&#39;&gt;
    07-05 14:29:16.792 D/OMG     ( 1260): FragmentA.onCreateView

It&#39;s never calling FragmentA.onSaveInstanceState and it creates a new FragmentA when you hit back.  However, if I&#39;m on FragmentA and I lock the screen, FragmentA.onSaveInstanceState does get called.  So weird...am I wrong in expecting a fragment added to the back stack to not need re-creation?  Here&#39;s what the [docs][2] say:

&gt; Whereas, if you do call addToBackStack() when removing a fragment,
&gt; then the fragment is stopped and will be resumed if the user navigates
&gt; back.

  [1]: https://stackoverflow.com/questions/11111649/savedinstancestate-when-restoring-fragment-from-back-stack
  [2]: http://developer.android.com/guide/components/fragments.html#Transactions

How can I maintain fragment state when added to the back stack?

I am learning how to use fragments. I have three instances of `Fragment` that are initialized at the top of the class. I am adding the fragment to an activity like this:

Declaring and initializing:

    Fragment A = new AFragment();
    Fragment B = new BFragment();
    Fragment C = new CFragment();

Replacing/Adding:

    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.content_frame, A);
    ft.addToBackStack(null);
    ft.commit();

These snippets are working properly. Every fragment is attached to the activity, and is saved to the back stack without any problem.

So when I launch `A`, `C`, and then `B`, the stack looks like this:

    | |
    |B|
    |C|
    |A|
    ___

And when I press the &#39;back&#39; button, `B` is destroyed and `C` is resumed.

But, when I launch fragment `A` a second time, instead of resuming from back stack, it is added at the top of the back stack

    | |
    |A|
    |C|
    |A|
    ___

But I want to resume `A` and destroy all fragments on top of it (if any). Actually, I just like the default back stack behavior. 

How do I accomplish this?

Expected: (`A` should be resumed and top fragments should be destroyed)

    | |
    | |
    | |
    |A|
    ___

**Edit: (suggested by A--C)**

This is my trying code:

    private void selectItem(int position) {
    		Fragment problemSearch = null, problemStatistics = null;
    		FragmentManager manager = getSupportFragmentManager();
    		FragmentTransaction ft = manager.beginTransaction();
    		String backStateName = null;
    		Fragment fragmentName = null;
    		boolean fragmentPopped = false;
    		switch (position) {
    		case 0:
    			fragmentName = profile;
    			break;
    		case 1:
    			fragmentName = submissionStatistics;
    			break;
    		case 2:
    			fragmentName = solvedProblemLevel;
    			break;
    		case 3:
    			fragmentName = latestSubmissions;
    			break;
    		case 4:
    			fragmentName = CPExercise;
    			break;
    		case 5:
    			Bundle bundle = new Bundle();
    			bundle.putInt(&quot;problem_no&quot;, problemNo);
    			problemSearch = new ProblemWebView();
    			problemSearch.setArguments(bundle);
    			fragmentName = problemSearch;
    			break;
    		case 6:
    			fragmentName = rankList;
    			break;
    		case 7:
    			fragmentName = liveSubmissions;
    			break;
    		case 8:
    			Bundle bundles = new Bundle();
    			bundles.putInt(&quot;problem_no&quot;, problemNo);
    			problemStatistics = new ProblemStatistics();
    			problemStatistics.setArguments(bundles);
    			fragmentName = problemStatistics;
    		default:
    			break;
    		}
    		backStateName = fragmentName.getClass().getName();
    		fragmentPopped = manager.popBackStackImmediate(backStateName, 0);
    		if (!fragmentPopped) {
    			ft.replace(R.id.content_frame, fragmentName);
    		}
    		ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
    		ft.addToBackStack(backStateName);
    		ft.commit();
                
            // I am using drawer layout
    		mDrawerList.setItemChecked(position, true);
    		setTitle(title[position]);
    		mDrawerLayout.closeDrawer(mDrawerList);
    	}

The problem is, when I launch `A` and then `B`, then press &#39;back&#39;, `B` is removed and `A` is resumed. and pressing &#39;back&#39; a second time should exit the app. But it is showing a blank window and I have to press back a third time to close it.

Also, when I launch `A`, then `B`, then `C`, then `B` again...

Expected:

    | |
    | |
    |B|
    |A|
    ___

Actual:

    | |
    |B|
    |B|
    |A|
    ___

Should I override `onBackPressed()` with any customization or am I missing something?

How to resume existing Fragment from BackStack

When i am clicking on **Logout** button in my **Profile** Activity i want to take user to **Login** page, where he needs to use new credentials.

Hence i used this code:

    Intent intent = new Intent(ProfileActivity.this,
    		LoginActivity.class);
    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); 
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(intent);

in the `onButtonClick` of the Logout button.

But the problem is when i click device back button on the Login Activity it takes me to the ProfileActivity. I was expecting the application should close when i press device back button on LoginActivity.

What am i doing wrong?

I also added `android:launchMode=&quot;singleTop&quot;` in the manifest for my **LoginActivity**

Thank You

Android: Remove all the previous activities from the back stack

I&#39;ve come across a bug in my application when it is launched using the **&quot;Open&quot;** button on the Google Play Store app (previously called Android Market). It seems that launching it from the Play Store uses a different `Intent` than launching it from the phone&#39;s application menu of icons. This is leading to multiple copies of the same Activity being launched, which are conflicting with each other.

**For example,** if my app consists of the Activities A-B-C, then this issue can lead to a stack of A-B-C-A.

I tried using `android:launchMode=&quot;singleTask&quot;` on all the Activities to fix this problem, but it has the unwanted side-effect of clearing the Activity stack to root, whenever I hit the HOME button. 

**The expected behavior is:** A-B-C -&gt; HOME -&gt; And when the app is restored, I need: A-B-C -&gt; HOME -&gt; A-B-C

Is there a good way to prevent launching multiple Activities of the same type, without resetting to the root activity when using the HOME button?




How to prevent multiple instances of an Activity when it is launched with different Intents

I&#39;ve got a massive problem with the way the android fragment backstack seems to work and would be most grateful for any help that is offered.

Imagine you have 3 Fragments

`[1] [2] [3]`

I want the user to be able to navigate `[1] &gt; [2] &gt; [3]` but on the way back (pressing back button) `[3] &gt; [1]`.

As I would have imagined this would be accomplished by not calling `addToBackStack(..)` when creating the transaction that brings fragment `[2]` into the fragment holder defined in XML.

The reality of this seems as though that if I dont want `[2]` to appear again when user presses back button on `[3]`, I must not call `addToBackStack` in the transaction that shows fragment `[3]`. This seems completely counter-intuitive (perhaps coming from the iOS world).

Anyway if i do it this way, when I go from `[1] &gt; [2]` and press back I arrive back at `[1]` as expected.

If I go `[1] &gt; [2] &gt; [3]` and then press back I jump back to `[1]` (as expected).
Now the strange behavior happens when I try and jump to `[2]` again from `[1]`. First of all `[3]` is briefly displayed before `[2]` comes into view. If I press back at this point `[3]` is displayed, and if I press back once again the app exits.

Can anyone help me to understand whats going on here? 

&lt;BR&gt;
And here is the layout xml file for my main activity:
&lt;BR&gt;

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;LinearLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
              android:layout_width=&quot;fill_parent&quot;
              android:layout_height=&quot;fill_parent&quot;
              android:orientation=&quot;vertical&quot; &gt;

    &lt;fragment
            android:id=&quot;@+id/headerFragment&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;wrap_content&quot;
            class=&quot;com.fragment_test.FragmentControls&quot; &gt;
        &lt;!-- Preview: layout=@layout/details --&gt;
    &lt;/fragment&gt;
    &lt;FrameLayout
            android:id=&quot;@+id/detailFragment&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;fill_parent&quot;

            /&gt;


&lt;/LinearLayout&gt;

&lt;BR&gt;
&lt;BR&gt;

**Update**
This is the code I&#39;m using to build by nav heirarchy

        Fragment frag;
        FragmentTransaction transaction;


        //Create The first fragment [1], add it to the view, BUT Dont add the transaction to the backstack
        frag = new Fragment1();

        transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.detailFragment, frag);
        transaction.commit();

        //Create the second [2] fragment, add it to the view and add the transaction that replaces the first fragment to the backstack
        frag = new Fragment2();

        transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.detailFragment, frag);
        transaction.addToBackStack(null);
        transaction.commit();


        //Create third fragment, Dont add this transaction to the backstack, because we dont want to go back to [2] 
        frag = new Fragment3();
        transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.detailFragment, frag);
        transaction.commit();


         //END OF SETUP CODE-------------------------
        //NOW:
        //Press back once and then issue the following code:
        frag = new Fragment2();
        transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.detailFragment, frag);
        transaction.addToBackStack(null);
        transaction.commit();

        //Now press back again and you end up at fragment [3] not [1]



Many thanks

Problems with Android Fragment back stack

I thought the system would reverse animations on the backstack when the back button is pressed when using fragments using the following code:

    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.setCustomAnimations(R.anim.slide_in, R.anim.hyperspace_out);
    ft.replace(R.id.viewContainer, new class(), &quot;layout&quot;).addToBackStack(null).commit();


How to Reverse Fragment Animations on BackStack?

How can I get the latest fragment instance added in backstack (if I do not know the fragment tag &amp; id)?

    FragmentManager fragManager = activity.getSupportFragmentManager();
    FragmentTransaction fragTransacion = fragMgr.beginTransaction();

    /****After add , replace fragments 
      (some of the fragments are add to backstack , some are not)***/
    
    //HERE, How can I get the latest added fragment from backstack ??

get the latest fragment in backstack

I&#39;m using the compatibility package to use Fragments with Android 2.2. 
When using fragments, and adding transitions between them to the backstack, I&#39;d like to achieve the same behavior of onResume of an activity, i.e., whenever a fragment is brought to &quot;foreground&quot; (visible to the user) after poping out of the backstack, I&#39;d like some kind of callback to be activated within the fragment (to perform certain changes on a shared UI resource, for instance).

I saw that there is no built in callback within the fragment framework. is there s a good practice in order to achieve this?

Fragments onResume from back stack

I have 2 activities: Main and List.

From Main you can open List; from List you can open Main.

I&#39;d like it so that every opening of List does **not** get saved into the &#39;history&#39;. So, pressing back from Main **cannot** return to List.

Is it possible?

Android: open activity without save into the stack

I have an activity A, which calls fragment Bf, which calls fragment Cf.  I want Bf to be placed in the backstack when Cf is called so that users can navigate back to it.  However, if a specific button is pressed in Cf, I would like Bf to be removed from the backstack.  Is this possible?

I see that there is a popBackStack() function.  However, I am a little confused on how this would work.  Is it safe to use this function?  Is there any possibility that an activity from a different application would be inserted after Bf on the backstack? 

Also, is there any way to alter the savedInstanceState of the fragment on the backstack? 

I just can&#39;t figure out how to do a robust test on the backstack using the emulator.

How to pop fragment off backstack

Is it possible to start an activity on the stack, clearing the entire history before it?

**The situation**

I have an activity stack that either goes A-&gt;B-&gt;C or B-&gt;C (screen A selects the users token, but many users only have a single token). 

In screen C the user *may* take an action which makes screen B invalid, so the application wants to take them to screen A, regardless of whether it is already in the stack. Screen A should then be the only item on the stack in my application.

**Notes**

There are many other similar questions, but I haven&#39;t found anything that answers this exact question. I tried calling `getParent().finish()` - this always results in a null pointer exception. `FLAG_ACTIVITY_CLEAR_TOP` only works if the activity is already on the stack. 


Clear the entire history stack and start a new activity on Android

I have a Fragment (I&#39;ll call it `pagerFragment`) that is added to the backstack and is visible. It holds a `viewPager` with a `FragmentPagerAdapter`. The `FragmentPagerAdapter` holds (let&#39;s say) two fragments: A and B.

First adding of the fragments works great.

Fragment A has a button that once clicked, adds a fragment (C) to the backstack.

The problem is this: if I add that fragment (C), and then click back, the `pagerAdapter` is empty, and I cannot see any fragments inside.

If I use a hack, and destroy the children fragments (A and B) in the `pagerFragment`s `onDestroyView()`, this solves the problem, although I don&#39;t wan&#39;t to use this hack.

Any ideas what the issue could be?




All Back Stack Solutions on Gang of Coders

Total of 18 Back Stack Solutions