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ActionBar Up button: go to previous Activity with prev fragment

I need your help regarding my application flow.
MainActivity (with Navigation Drawer)
-- Fragment A
-- Fragment B
-- Fragment C (articles list view)
ArticleActivity
-- Fragment D (article detail view)
Fragment C (MainActivity) displays a list of items (ListView). Selecting an item leads to fragment D (handle by ArticleActivity) which presents that item in more detail.
Fragment D displays a "Up" button that should allow the user to returns to previous screen (the detail view). The problem is that when the "Up" button is pressed the previous activity is displayed but not the previous activated fragment (the defaut fragment (A) is instead displayed).
My current code:
public class FragmentC extends Fragment {
public static FragmentC newInstance() {
FragmentC fragment = new FragmentC();
return fragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_courses, container, false);
...
// Somewhere in my code I have a onClickListener to launch the detail view activity
setOnClickListener(new OnCardClickListener() {
#Override
public void onClick(Card card, View view) {
Intent i = new Intent(getActivity(), ArticleActivity.class);
i.putExtra("articleIndex", mArticle.getId());
startActivity(i);
}
});
...
return view;
}
}
public class ArticleActivity extends Activity {
private long mArticleIndex;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_course);
mArticleIndex = getIntent().getExtras().getLong("articleIndex", 0);
// Set up action bar:
// Specify that the Home button should show an "Up" caret, indicating that touching the
// button will take the user one step up in the application's hierarchy.
final ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
// Place an ArticleFragment as our content pane
ArticleFragment fragment = ArticleFragment.newInstance(mArticleIndex);
getFragmentManager().beginTransaction().replace(R.id.container, fragment).commit();
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This is called when the Home (Up) button is pressed in the action bar.
Intent upIntent = new Intent(this, MainActivity.class);
upIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(upIntent);
finish();
return true;
}
return super.onOptionsItemSelected(item);
}
}
I think that I can resolve this issue by passing parameters to my Intent. For example i.putExtra("displayFragment", FragmentD) and then on the MainActivity retrieve it and tell to the FragmentManager to display the wanted fragment. I do not know if it's can work.
But it's maybe not the right way to achieve that?
Do you have any better workaround?

Replacing fragment on the fly

Android Studio 0.5.8
Hello,
I have one activity (MainActivity) that will host 2 fragments (ListAddressBookFragment, AddAddressBookFragment) (only one at a time). The initial fragment will be the ListAddressBookFragment and will be inflated when MainActivity onCreate gets called.
/* MainActivity.java */
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/* Add and display fragment */
FragmentManager fragmentManager = getSupportFragmentManager();
Fragment fragment = fragmentManager.findFragmentById(R.id.flFragmentContainer);
/* Create new fragment if this hasn't already been done */
if(fragment == null) {
fragment = new ListAddressBookFragment();
fragmentManager.beginTransaction()
.add(R.id.flFragmentContainer, fragment)
.commit();
}
}
In the ListAddressBookFragment I have a option menu to add a new addressbook item. So this will call call MainActivity. So I want to replace ListAddressBookFragment with AddAddressBookFragment. However, because the code above is hardcoded I am wondering is there anyway to do this on the fly?
/* ListAddressBookFragment.java */
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.new_addressbook) {
Intent intent = new Intent(getActivity(), MainActivity.class);
startActivity(intent);
return true;
}
return super.onOptionsItemSelected(item);
}
Many thanks for any suggestions,

I would recommend you to read this article, Communicating with fragments
Basically, you need to call
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, newFragment);
Also, consider using interface within fragment that activity implements.

Why don't you pass data to the MainActivity to indicate the mode you want the activity to be in?
intent.putExtra("mode", "addressbook");
In the MainActivity, you do the below.
String mode = (String)getIntent().getStringExtra("mode");
if ("addressbook".equals(mode)) {
// Address book fragment
} else {
// ListAddressBookFragment
}
Good Luck

Get data result from second Fragment

In my MainActivity extends FragmentActivity, I have a FragmentA, When I press a Button in FragmentA, I call to FragmentB.
FragmentB f = FragmentB.newInstance(1);
getSupportFragmentManager().beginTransaction().replace(R.id.llMain, f).addToBackStack(null).commit();
In FragmentB, I create a Object People p1(with Name and age) . And When I press a Button B in FragmentB, I call
getFragmentManager().popBackStack();
It will return FragmentA,
So, I want to pass data Object People p1 from FragmentB to FragmentA. What do i have to do?
I try to search but can't find a solution.

create CallBack in your Fragment and handle it in FragmentActivity,
google example has this realization
declaring OnHeadlineSelectedListener callback
public class HeadlinesFragment extends ListFragment {
OnHeadlineSelectedListener mCallback;
// The container Activity must implement this interface so the frag can deliver messages
public interface OnHeadlineSelectedListener {
/** Called by HeadlinesFragment when a list item is selected */
public void onArticleSelected(int position);
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// We need to use a different list item layout for devices older than Honeycomb
int layout = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
android.R.layout.simple_list_item_activated_1 : android.R.layout.simple_list_item_1;
// Create an array adapter for the list view, using the Ipsum headlines array
setListAdapter(new ArrayAdapter<String>(getActivity(), layout, Ipsum.Headlines));
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception.
try {
mCallback = (OnHeadlineSelectedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnHeadlineSelectedListener");
}
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Notify the parent activity of selected item
mCallback.onArticleSelected(position);
// Set the item as checked to be highlighted when in two-pane layout
getListView().setItemChecked(position, true);
}
Realize callback method in FragmentActivity and send (by .setArguments()) data from HeadLinesFragment to ArticleFragment, if ArticleFragment is available
public class MainActivity extends FragmentActivity
implements HeadlinesFragment.OnHeadlineSelectedListener {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.news_articles);
// Check whether the activity is using the layout version with
// the fragment_container FrameLayout. If so, we must add the first fragment
if (findViewById(R.id.fragment_container) != null) {
// However, if we're being restored from a previous state,
// then we don't need to do anything and should return or else
// we could end up with overlapping fragments.
if (savedInstanceState != null) {
return;
}
// Create an instance of ExampleFragment
HeadlinesFragment firstFragment = new HeadlinesFragment();
// In case this activity was started with special instructions from an Intent,
// pass the Intent's extras to the fragment as arguments
firstFragment.setArguments(getIntent().getExtras());
// Add the fragment to the 'fragment_container' FrameLayout
getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_container, firstFragment).commit();
}
}
public void onArticleSelected(int position) {
// The user selected the headline of an article from the HeadlinesFragment
// Capture the article fragment from the activity layout
ArticleFragment articleFrag = (ArticleFragment)
getSupportFragmentManager().findFragmentById(R.id.article_fragment);
if (articleFrag != null) {
// If article frag is available, we're in two-pane layout...
// Call a method in the ArticleFragment to update its content
articleFrag.updateArticleView(position);
} else {
// If the frag is not available, we're in the one-pane layout and must swap frags...
// Create fragment and give it an argument for the selected article
ArticleFragment newFragment = new ArticleFragment();
Bundle args = new Bundle();
args.putInt(ArticleFragment.ARG_POSITION, position);
newFragment.setArguments(args);
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack so the user can navigate back
transaction.replace(R.id.fragment_container, newFragment);
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}
}

You should use an interface within Activity for communication between fragments. Check this android training lesson.
All Fragment-to-Fragment communication is done through the associated
Activity. Two Fragments should never communicate directly.
You can pass arguments to a Fragment with Bundle. Change your code to:
FragmentB f = FragmentB.newInstance(1);
Bundle args = new Bundle();
args.putString("NAME", name);
args.putInt("AGE", age);
f.setArguments(args);
getSupportFragmentManager().beginTransaction().replace(R.id.llMain, f).addToBackStack(null).commit();
and then retrieve the arguments for example in FragmentA's onCreateView with:
int age = getArguments().getInt("AGE");
//or with a second parameter as the default value
int age = getArguments().getInt("AGE", 0);
If you want to pass the whole People object to the Bundle, you need to make the class serializable. I think it's easier to pass the variables and then recreate the object.

Handling ActionBar title with the fragment back stack?

I have an Activity where I load in a ListFragment and, upon clicking, it drills down a level and a new type of ListFragment is shown, replacing the original one (using the showFragment method below). This is placed on the back stack.
At the beginning, the activity shows the default title in the action bar (i.e. it's set automatically based on the application's android:label).
When showing the list for the next level in the hierarchy, the name of the item clicked on should become the action bar's title.
However, when pressing Back, I would like the original default title to be restored. This isn't something FragmentTransaction knows about, so the title isn't restored.
I've vaguely read about FragmentBreadCrumbs, but this seems to require using a custom view. I'm using ActionBarSherlock and would prefer to not have my own custom title view.
What is the best way of doing this? Is it possible without a load of boilerplate code and having to keep track of the titles shown along the way?
protected void showFragment(Fragment f) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragment_container, f);
ft.addToBackStack(null);
ft.commit();
}

In every fragment and every activity I change the title like this. This way the active title will always be correct:
#Override
public void onResume() {
super.onResume();
// Set title
getActivity().getActionBar()
.setTitle(R.string.thetitle);
}
There is some cases where onResume isn't called inside fragments. In some of these cases we can use:
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if(isVisibleToUser) {
// Set title
getActivity().getActionBar()
.setTitle(R.string.thetitle);
}
}

As the original answer is quite old, this might come of help as well. As the documentation states, one might want to register a listener to listen on the back stack changes in the hosting Activity:
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
public void onBackStackChanged() {
// Update your UI here.
}
});
Then, identify the situation in the callback method and set a proper title, without accessing the ActionBar from the Fragment.
This is a more elegant solution as the Fragment doesn't have to know about the ActionBar existence and Activity is usually the place that is managing the backstack so having it handled over there seems to be more appropriate. Fragment should at all time be considered only by its own content, not the surroundings.
More on the topic in the documentation.

Let the controlling activity do all the work as follows:
Listen for backstack events (in onCreate() of activity):
// Change the title back when the fragment is changed
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
Fragment fragment = getFragment();
setTitleFromFragment(fragment);
}
});
Get the current fragment from the container:
/**
* Returns the currently displayed fragment.
* #return
* Fragment or null.
*/
private Fragment getFragment() {
Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.container);
return fragment;
}
Set the fragment inside the content view:
private void setFragment(Fragment fragment, boolean addToBackStack) {
// Set the activity title
setTitleFromFragment(fragment);
.
.
.
}

Warpzit is right. This also solves title problem when orientation of device is changed. Also if you use support v7 for action bar, you can get action bar from fragment like this :
#Override
public void onResume() {
super.onResume();
((ActionBarActivity)getActivity()).getSupportActionBar().setTitle("Home");
}

It is best to let the OS do as much of the work as possible.
Assuming each fragment is properly named using .addToBackStack("title") then
you can override onBackPressed something like this to achieve desired behavior:
// this example uses the AppCompat support library
// and works for dynamic fragment titles
#Override
public void onBackPressed() {
FragmentManager fragmentManager = getSupportFragmentManager();
int count = fragmentManager.getBackStackEntryCount();
if (count <= 1) {
finish();
}
else {
String title = fragmentManager.getBackStackEntryAt(count-2).getName();
if (count == 2) {
// here I am using a NavigationDrawer and open it when transitioning to the initial fragment
// a second back-press will result in finish() being called above.
mDrawerLayout.openDrawer(mNavigationDrawerFragment.getView());
}
super.onBackPressed();
Log.v(TAG, "onBackPressed - title="+title);
getSupportActionBar().setTitle(title);
}
}

I use a similar solution to Lee approach, but replacing onBackStackChanged() method instead.
First I set the fragment name when adding the transaction to the back stack.
getSupportFragmentManager().beginTransaction()
.replace(R.id.frame_content, fragment)
.addToBackStack(fragmentTitle)
.commit();
Then I override the onBackStackChanged() method and I call setTitle() with the last backstack entry name.
#Override
public void onBackStackChanged() {
int lastBackStackEntryCount = getSupportFragmentManager().getBackStackEntryCount() - 1;
FragmentManager.BackStackEntry lastBackStackEntry =
getSupportFragmentManager().getBackStackEntryAt(lastBackStackEntryCount);
setTitle(lastBackStackEntry.getName());
}

Use Fragments method:
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
It is called on every Fragment appearance, but onResume is not.

The best approach is to make use of the android provided Interface OnBackStackChangedListener method onBackStackChanged().
Lets say we have a navigation drawer with 4 options to which the user can navigate to. In that case we will have 4 fragments. Lets see the code first and then I will explain the working.
private int mPreviousBackStackCount = 0;
private String[] title_name = {"Frag1","Frag2","Frag3","Frag4"};
Stack<String> mFragPositionTitleDisplayed;
public class MainActivity extends ActionBarActivity implements FragmentManager.OnBackStackChangedListener
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
....
....
....
getSupportFragmentManager().addOnBackStackChangedListener(this);
mFragPositionTitleDisplayed = new Stack<>();
}
public void displayFragment() {
Fragment fragment = null;
String title = getResources().getString(R.string.app_name);
switch (position) {
case 0:
fragment = new Fragment1();
title = title_name[position];
break;
case 1:
fragment = new Fragment2();
title = title_name[position];
break;
case 2:
fragment = new Fragment3();
title = title_name[position];
break;
case 3:
fragment = new Fragment4();
title = title_name[position];
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container_body, fragment)
.addToBackStack(null)
.commit();
getSupportActionBar().setTitle(title);
}
}
#Override
public void onBackStackChanged() {
int backStackEntryCount = getSupportFragmentManager().getBackStackEntryCount();
if(mPreviousBackStackCount >= backStackEntryCount) {
mFragPositionTitleDisplayed.pop();
if (backStackEntryCount == 0)
getSupportActionBar().setTitle(R.string.app_name);
else if (backStackEntryCount > 0) {
getSupportActionBar().setTitle(mFragPositionTitleDisplayed.peek());
}
mPreviousBackStackCount--;
}
else{
mFragPositionTitleDisplayed.push(title_name[position]);
mPreviousBackStackCount++;
}
}
In the code shown we have the displayFragment() method. Here I display the fragment on the basis of option chosen from the navigation drawer.The variable position corresponds to the position of the item clicked from the ListView or RecyclerView in the navigation drawer. I set the actionbar title accordingly with getSupportActionBar.setTitle(title), where the title stores the appropriate title name.
Whenever we click the item from nav drawer a fragment is displayed depending on the item clicked to the user. But on the back end side this fragment is added to the backstack and the method onBackStachChanged(), gets hit. What I have done is that I have created a variable mPreviousBackStackCount and initialized it to 0. I have also created an additional stack which will store the action bar title names. Whenever I add a new fragment to the backstack, I add the corresponding title name to my created stack. On the opposite side whenever I press the back button onBackStackChanged() is called and I pop the last title name from my stack and set the title to the name derived by the peek() method of the stack.
Example:
Lets say our android backstack is empty:
Press Choice 1 from nav drawer:
onBackStachChanged() is called and the Fragment 1 is added to android backstack, backStackEntryCount is set to 1 and Frag1 is pushed to my stack and size of mFragPositionTitleDisplayed becomes 1.
Press Choice 2 from nav drawer:
onBackStachChanged() is called and the Fragment 2 is added to android backstack, backStackEntryCount is set to 2 and Frag2 is pushed to my stack and size of mFragPositionTitleDisplayed becomes 2.
Now we have 2 elements both in the android stack and my stack. When you press back button onBackStackChanged() is called and the value of backStackEntryCount is 1. The code enters the if part and pops out the last entry from my stack. So, the android backstack has only 1 fragment - "Fragment 1" and my stack has only 1 title - "Frag1". Now I just peek() the title from my stack and set the action bar to that title.
Remember: To set the action bat title use peek() and not pop() else your application will crash when you open more than 2 fragments and try to go back by pressing back button.

You can Solve with onKeyDown!
I have a bool
mainisopen=true <-- MainFragment is Visible
other Fragment mainisopen=false
and here is My Code:
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && mainisopen == false) {
mainisopen = true;
HomeFrag fragment = new HomeFrag();
FragmentTransaction fragmentTransaction =
getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragmet_cont, fragment);
fragmentTransaction.commit();
navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.getMenu().findItem(R.id.nav_home).setChecked(true);
navigationView.setNavigationItemSelectedListener(this);
this.setTitle("Digi - Home"); //Here set the Title back
return true;
} else {
if (keyCode == KeyEvent.KEYCODE_BACK && mainisopen == true) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Wollen sie die App schliessen!");
builder.setCancelable(true);
builder.setPositiveButton("Ja!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
System.exit(1);
}
});
builder.setNegativeButton("Nein!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(getApplicationContext(), "Applikation wird fortgesetzt", Toast.LENGTH_SHORT).show();
}
});
AlertDialog dialog = builder.create();
dialog.show();
return true;
}
return super.onKeyDown(keyCode, event);
}
}

As described here my solution is adding this code to MainActivity onCreate method(): and changing actionbar title
FragmentManager fragmentManager=getSupportFragmentManager();
fragmentManager.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
Fragment currentFragment = fragmentManager.findFragmentById(R.id.My_Container_1_ID);
currentFragment.onResume();
}
});
and changing actionbar title in fragment's onResume() method
#Override
public void onResume() {
super.onResume();
AppCompatActivity activity = (AppCompatActivity) getActivity();
ActionBar actionBar = activity.getSupportActionBar();
if(actionBar!=null) {
actionBar.setTitle("Fragment Title");
actionBar.setSubtitle("Subtitle");
}
}

To update the actionbar title on back press. Just simply put
getActivity.setTitle("title")
inside onCreateView method.

After orientation change, optionsmenu of fragment doesn't disappear

I implemented my layout based on this tutorial: http://android-developers.blogspot.hu/2011/02/android-30-fragments-api.html
The differences are:
I have different fragments to show, based on the choice in the left
list
The "details fragments" (those that come to the right) have different options menus
My problem is that if I have already selected something from the left and then rotate the phone to portrait, the last optionsmenu is still there and is visible.
I think the problem comes from the last active "details" fragment is recreated after the orientation change. to test it I created these two methods:
#Override
public void onStart() {
super.onStart();
setHasOptionsMenu(true);
}
#Override
public void onStop() {
super.onStop();
setHasOptionsMenu(false);
}
And I'm showing the right fragment like this:
case R.id.prefs_medicines:
if (mDualPane) {
// Check what fragment is shown, replace if needed.
View prefsFrame = getActivity().findViewById(R.id.preferences);
if (prefsFrame != null) {
// Make new fragment to show this selection.
MedicineListF prefF = new MedicineListF();
// Execute a transaction, replacing any existing
// fragment with this one inside the frame.
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.preferences, prefF);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
}
} else {
// Otherwise we need to launch a new activity to display
// the dialog fragment with selected text.
Intent intent = new Intent();
intent.setClass(getActivity(), MedicinePrefsActivity.class);
startActivity(intent);
}
break;
in one of my "details" fragment. when I debugged it, the onstart was called after the rotation.
The problem in pictures:
1: in landscape it's OK
Landscape mode http://img834.imageshack.us/img834/8918/error1d.png
2: in portrait: optionsmenu not needed
Portrait mode http://img860.imageshack.us/img860/8636/error2r.png
How can I get rid of the optionsmenu in portrait mode?

I had the same problem, and resolved it by setting setHasOptionsMenu(true) in the fragment only when savedInstanceState is null. If onCreate gets a bundle then the fragment is being restored in an orientation change to portrait, so don't display the menu.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(savedInstanceState == null) {
setHasOptionsMenu(true);
}
}