Develop Reference

Android - Show fragment on resume

I currently have a navigation drawer, which has a few fragments (Home, Help, About) in my activity. On startup it opens up Home. The issue i'm having is that when i go to another fragment such as Help and then proceed to put the phone to sleep and subsequently turn on the phone back on it'll always return to Home instead of help.
I'm quite new to lifecycles but was hoping to get some feedback on how to resume from a different fragment.
EDIT: Provided relevant code
Update: Realised that this happens because i reinit the views on resume.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initializeUI();
}
private void initializeUI() {
fragAbout = new About();
fragHelp = new Help();
fragHome = new MyViewPager();
// Adding fragments to activity
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.main_activity_fraglayout, fragHome);
transaction.commit();
...
}
private void addDrawerItems() {
...
DrawerItemAdapter drawerAdapter = new DrawerItemAdapter(this, R.layout.nav_list_row, drawerItems);
mDrawerList.setAdapter(drawerAdapter);
mDrawerList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
switch (position) {
case 0:
...
newFragOnClick(fragHome, "Home");
break;
case 1:
...
newFragOnClick(fragSettings, "Help");
break;
case 2:
...
newFragOnClick(fragAbout, "About");
break;
default:
break;
}
}
});
}
private void newFragOnClick(Fragment frag, String actionBarTitle){
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.main_activity_fraglayout, frag);
transaction.commit();
}

Use sharedpreferences to save the current tab position and in onResume() use it to move to the saved position.

Fragments stack Android

Imagine one activity with 3 fragments: starts showing the first one, select a menu option and go to the second one, select another option and go to the 3rd fragment and select again the first option an return to the second one.
f1 -> f2 -> f3 -> f2
When I press back I want the app returns to fragment 3 and when I press back again it should return to fragment 1 and if press back again, close the app.
Something like if the fragment exists, move it to top of the stack and if not, create it.
Thank you!

Here is solution I came up over time.
The idea is following, you need to keep a stack data structure and whenever you add a fragment add it to stack as well, then override onBackPress method and check if stack is not empty then replace your fragment container with new fragment from top of the stack when it is empty do super.onbackpress
So here is a parent class for all kind of fragment based navigation.
public abstract class FragmentsStackActivity extends BaseActivity {
public static final String TAG_BUNDLE = "bundle_tag";
protected final Bundle fragmentArgs = new Bundle();
protected Stack<Fragment> fragments = new Stack<>();
abstract protected void setupFragments();
public void setFragmentArguments(Fragment fragment, Bundle arguments){
if(!fragments.isEmpty() && fragments.peek()!=fragment){
fragment.setArguments(arguments);
}
}
public void setFragmentFromStack() {
if(!fragments.isEmpty()) {
Fragment fragment = fragments.peek();
final Fragment oldFragment = getSupportFragmentManager().findFragmentById(R.id.fragment_container);
if (oldFragment == null || oldFragment != fragment) {
getFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
final FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
//transaction.setCustomAnimations(R.anim.animator_left_right_in, R.anim.animator_left_right_in);
transaction.replace(R.id.fragment_container, fragment).commit();
}
}else {
finish();
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
//TODO need to save fragment stack
}
}
example of an activity that extends this class
public class LoginActivity extends FragmentsStackActivity{
private final MyFragment1 fragment1 = new MyFragment1();
private final MyFragment2 fragment2 = new MyFragment2();
private final User mUser = new User();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
setupFragments();
setFragmentFromStack();
}
#Override
protected void setupFragments() {
fragments.add(fragment2);
//fragment2.setNotifier(this); // I use notifiers listener but you can choose whatever convenient for you
Bundle fragmentArgs = new Bundle();
fragmentArgs.putBoolean(Constants.TAG_LOGIN, true);
fragmentArgs.putParcelable(User.TAG, mUser);
fragmentArgs.putInt(Constants.TYPE, getIntent().getIntExtra(Constants.TYPE, 0));
fragment2.setArguments(fragmentArgs);
//fragment1.setNotifier(this); // I use notifiers listener but you can choose whatever convenient for you
}
// this method teals with handling messages from fragments in order to provide navigation
// when some actions taken inside the fragment, you can implement your own version
public void onReceiveMessage(String tag, Bundle bundle) {
switch (tag) {
case MyFragment2.TAG_BACK:
case MyFragment1.TAG_BACK:
fragments.pop();
setFragmentFromStack();
break;
case MyFragment2.TAG_NEXT:
fragment1.setArguments(bundle);
fragments.add(fragment1);
setFragmentFromStack();
break;
case MyFragment1.TAG_NEXT:
goToWelcomeScreen(bundle);
finish();
break;
}
}
private void goToWelcomeScreen(Bundle bundle){
}
}

You can implement this with the help of the following code:
// transaction.replace(R.id.detailFragment, frag1);
Transaction.remove(null).add(frag1) // frag1 on view
// transaction.replace(R.id.detailFragment, frag2).addToBackStack(null);
Transaction.remove(frag1).add(frag2).addToBackStack(null) // frag2 on view
// transaction.replace(R.id.detailFragment, frag3);
Transaction.remove(frag2).add(frag3) // frag3 on view
And for better understanding, have a ook at the following snippet:
// Works with either the framework FragmentManager or the
// support package FragmentManager (getSupportFragmentManager).
getSupportFragmentManager().beginTransaction()
.add(detailFragment, "detail")
// Add this transaction to the back stack
.addToBackStack()
.commit();
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
public void onBackStackChanged() {
// Update your UI here.
}
});
have a look here http://developer.android.com/training/implementing-navigation/temporal.html

Handle Fragment On Screen Orientation Changes?

I am useing This Sort of Code To Handle Three Fragment in Main Activity ...
FragmentA is Fixed it One Frame .. I change FragmentB and FragmentC on Button Click on FragmentA.
his Code is Running well either in Portrait or Landscape view .Here is The Code bellow.
public class MainActivity extends FragmentActivity implements
OnSwitchClickListener {
FragmentManager manager;
FragmentA fragA;
FragmentB fragB;
FragmentC fragC;
boolean fragBSet = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fragA = new FragmentA();
fragB = new FragmentB();
fragC = new FragmentC();
manager = getSupportFragmentManager();
FragmentTransaction ft = manager.beginTransaction();
ft.add(R.id.a_container, fragA, "frag A");
if (fragBSet) {
ft.add(R.id.bc_container, fragC, "frag C");
} else {
ft.add(R.id.bc_container, fragB, "frag B");
}
fragBSet = true;
ft.commit();
}
#Override
public void onSwitchClick(View v) {
Toast.makeText(getApplicationContext(), "Switch clkick from Activity",
Toast.LENGTH_LONG).show();
FragmentTransaction ft = manager.beginTransaction();
if (fragBSet) {
ft.remove(fragB);
ft.add(R.id.bc_container, fragC, "frag C");
fragBSet = false;
} else {
ft.remove(fragC);
ft.add(R.id.bc_container, fragB, "frag B");
fragBSet = true;
}
ft.commit();
}
This Code is Running well either in Portrait or Landscape view ... But When Ever I change the Orientation The Two Fragments Override One Another.
Need Solution.

When your orientation change, your Activity is recreated.
"In the scenario where a user rotates their device, Android will destroy your
application’s activity(s). Before destroying them it calls, onSaveInstanceState,
allowing developers to persist data. Once the activity is recreated post
rotation, the OS will call onRestoreInstanceState giving developers a chance to
restore the application state pre-rotation."
You should try to save your Fragments State.
putFragment: Put a reference to a fragment in a Bundle. This Bundle can be persisted as saved state, and when later restoring getFragment(Bundle, String) will return the current instance of the same fragment.
#Override
protected void onSaveInstanceState(Bundle outState) {
FragmentManager manager = getFragmentManager();
manager.putFragment(outState, MyFragment.TAG, mMyFragment);
}
getFragment: Retrieve the current Fragment instance for a reference previously placed with putFragment(Bundle, String, Fragment).
private void instantiateFragments(Bundle inState) {
FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
if (inState != null) {
mMyFragment = (MyFragment) manager.getFragment(inState, MyFragment.TAG);
} else {
mMyFragment = new MyFragment();
transaction.add(R.id.fragment, mMyFragment, MyFragment.TAG);
transaction.commit();
}
}
restoreFragment:
#Override
protected void onRestoreInstanceState(Bundle inState) {
instantiateFragments(inState);
}
Hope this helps.

Fragments Behave Weirdly When Using addToBackStack()

An SSCCE for this issue is available on GitHub.
For future readers, the original example is on a branch of the same project, and the fix is available in this diff.
This SSCCE has a ListView and a row of buttons. The buttons are supposed to change the data in the ListView, and the listView rows (when clicked) are supposed to open a new fragment and advance the backstack while staying in the same activity.
If do the following things, it produces the following result:
Open the app.
Tap the ListView. - FragmentTransaction.replace(...) with addToBackStack(true)
Tap any of the buttons. - FragmentTransaction.replace(...) with addToBackStack(false)
Tap the back button.
Result:
Both fragments become visible, but I only want the first loaded fragment (ListTwoFragment in code) to display. Is this how fragments are supposed to work? If so, how can I get the desired effect?
MainActivity.java:
public class MainActivity extends FragmentActivity implements ListTwoFragment.Callbacks,
ListThreeFragment.Callbacks {
public static final String KEY_ARGS = "args";
private String curUri = "";
private String curArgs = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
selectContent(false);
}
private void selectContent(boolean addToBackStack) {
Fragment fragment;
if (curUri.isEmpty()) {
// Use default fragment
fragment = new ListTwoFragment();
curUri = ListTwoFragment.class.getName();
}
else {
try {
Class<Fragment> fragmentClass = (Class<Fragment>) Class.forName(curUri);
fragment = fragmentClass.newInstance();
}
catch (Exception e) { // ClassNotFound, IllegalAccess, etc.
return;
}
}
// Configure fragment
Bundle args = new Bundle();
args.putString(KEY_ARGS, curArgs);
fragment.setArguments(args);
attachFragment(fragment, addToBackStack, curUri + ";" + curArgs, R.id.fragment_container);
}
protected void attachFragment(Fragment fragment, boolean addToBackStack, String tag, int replaceId) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(replaceId, fragment, tag);
if (addToBackStack) transaction.addToBackStack(tag);
transaction.commit();
}
#Override
public void onTwoButtonClick(String title) {
curUri = ListTwoFragment.class.getName();
curArgs = title;
selectContent(false);
}
#Override
public void onTwoListClick() {
curUri = ListThreeFragment.class.getName();
curArgs = "";
selectContent(true);
}
#Override
public void onThreeButtonClick(String title) {
curUri = ListThreeFragment.class.getName();
curArgs = title;
selectContent(false);
}
}

I'm working with Fragments to, and the way I'm doing it:
to go forward (add to stack), and backwords (remove from stack) are two different functions
to Add to Stack and change Fragment:
public void changeFragmentAddToStack(Fragment myNewFragment) {
FragmentTransaction t = getSupportFragmentManager().beginTransaction();
t.add(R.id.main_fragment, myNewFragment);
t.addToBackStack(null);
t.commit();
}
To go back Stack:
public void goBackStackMain() {
FragmentManager man = getSupportFragmentManager();
if(man.getBackStackEntryCount()>0){
man.popBackStack(man.getBackStackEntryAt(0).getName(), FragmentManager.POP_BACK_STACK_INCLUSIVE);
}
}
And if you want to do both: To go back stack and change fragment:
public void goBackStackAndReplaceFragment(Fragment myNewFragment) {
FragmentManager man = getSupportFragmentManager();
if(man.getBackStackEntryCount()>0){
int n = man.getBackStackEntryCount();
man.popBackStack(man.getBackStackEntryAt(n-1).getName(), FragmentManager.POP_BACK_STACK_INCLUSIVE);
}
FragmentTransaction t = getSupportFragmentManager().beginTransaction();
t.replace(R.id.main_fragment, myNewFragment);
t.commit();
}
I hope to help you !

Android replace the current fragment with another fragment

I just started with fragment design for HoneyComb. I created two fragments. When i click a button in the left side fragment, a new fragment is created in right side. Meanwhile when i click a button in the right fragment(ie. DetialsFragment in my code below should be replaced by another fragment.
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<fragment class="com.fragment.example.Titles"
android:id="#+id/titles" android:layout_weight="1"
android:layout_width="0px"
android:layout_height="match_parent" />
<FrameLayout android:id="#+id/details" android:layout_weight="1"
android:layout_width="0px"
android:layout_height="match_parent" />
</LinearLayout>
FragmentExample.java
public class FragmentExample extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
Titles.java
public class Titles extends Fragment {
public FragmentTransaction ft;
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.main1, null);
Button button1 = (Button)v.findViewById(R.id.button1);
button1.setText("santhosh");
button1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
DetailsFragment details = (DetailsFragment)
getFragmentManager().findFragmentById(R.id.details);
if (details == null || details.getShownIndex() != 1) {
// Make new fragment to show this selection.
details = DetailsFragment.newInstance(1);
// Execute a transaction, replacing any existing
// fragment with this one inside the frame.
ft
= getFragmentManager().beginTransaction();
ft.add(R.id.details, details, "detail");
ft.setTransition(
FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
}
}
});
return v;
}
}
DetailsFragment.java
public class DetailsFragment extends Fragment {
/**
* Create a new instance of DetailsFragment, initialized to
* show the text at 'index'.
*/
Titles title = new Titles();
String[] titles = {"Title1", "Title2", "Title3", "Title4"};
public static DetailsFragment newInstance(int index) {
DetailsFragment f = new DetailsFragment();
// Supply index input as an argument.
Bundle args = new Bundle();
args.putInt("index", index);
f.setArguments(args);
return f;
}
public int getShownIndex() {
return getArguments().getInt("index", 0);
}
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
if (container == null) {
// Currently in a layout without a container, so no
// reason to create our view.
return null;
}
Button button = new Button(getActivity());
button.setText("Next");
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
});
return button;
}
}

Then provided your button is showing and the click event is being fired you can call the following in your click event:
final FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.details, new NewFragmentToReplace(), "NewFragmentTag");
ft.commit();
and if you want to go back to the DetailsFragment on clicking back ensure you add the above transaction to the back stack, i.e.
ft.addToBackStack(null);
Or am I missing something? Alternatively some people suggest that your activity gets the click event for the button and it has responsibility for replacing the fragments in your details pane.

Latest Stuff
Okay. So this is a very old question and has great answers from that time. But a lot has changed since then.
Now, in 2020, if you are working with Kotlin and want to change the fragment then you can do the following.
Add Kotlin extension for Fragments to your project.
In your app level build.gradle file add the following,
dependencies {
def fragment_version = "1.2.5"
// Kotlin
implementation "androidx.fragment:fragment-ktx:$fragment_version"
// Testing Fragments in Isolation
debugImplementation "androidx.fragment:fragment-testing:$fragment_version"
}
Then simple code to replace the fragment,
In your activity
supportFragmentManager.commit {
replace(R.id.frame_layout, YourFragment.newInstance(), "Your_TAG")
addToBackStack(null)
}
References
Check latest version of Fragment extension
More on Fragments

You can try below code. it’s very easy method for push new fragment from old fragment.
private int mContainerId;
private FragmentTransaction fragmentTransaction;
private FragmentManager fragmentManager;
private final static String TAG = "DashBoardActivity";
public void replaceFragment(Fragment fragment, String TAG) {
try {
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(mContainerId, fragment, tag);
fragmentTransaction.addToBackStack(tag);
fragmentTransaction.commitAllowingStateLoss();
} catch (Exception e) {
// TODO: handle exception
}
}

Use android.support.v4.app for FragmentManager & FragmentTransaction in your code, it has worked for me.
DetailsFragment detailsFragment = new DetailsFragment();
android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.details,detailsFragment);
fragmentTransaction.commit();

If you have a handle to an existing fragment you can just replace it with the fragment's ID.
Example in Kotlin:
fun aTestFuction() {
val existingFragment = MyExistingFragment() //Get it from somewhere, this is a dirty example
val newFragment = MyNewFragment()
replaceFragment(existingFragment, newFragment, "myTag")
}
fun replaceFragment(existing: Fragment, new: Fragment, tag: String? = null) {
supportFragmentManager.beginTransaction().replace(existing.id, new, tag).commit()
}

Updated Answer (Working for Overlap problem as well)
#aniket-thakur(https://stackoverflow.com/users/2396539/aniket-thakur) gave correct answer. Thank you for that!
But, getFragmentManager() is deprecated, so following code did work for me.
final FragmentTransaction ft = getParentFragmentManager().beginTransaction();
ft.replace(R.id.nav_host_fragment, new GalleryFragment(), "NewFragmentTag");
ft.addToBackStack(null);
ft.commit();

it's very simple how to replace with Fragment.
DataFromDb changeActivity = new DataFromDb();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.changeFrg, changeActivity);
transaction.commit();