Develop Reference

FragmentTransaction show() doesn't work on specific fragment after rotate

I have a fragment with ActionBar.TabListener. Inside the TabListener I call to show a fragment if the fragment has already been created.
This works on portrait for all fragments, and on landscape for all fragments except one that contains a pagerViewer. For this problematic fragment, when the phone rotates (and re-select the tab), nothing displays.
Here's how I'm creating the fragments (condensed):
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.app.ActionBar.Tab;
import android.support.v4.app.FragmentActivity;
public class MainFragmentActivity extends FragmentActivity implements ResultsListener
{
FragmentManager fragment_manager;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main_fragment);
bundle = savedInstanceState;
System.out.println("bundle = " + bundle);
fragment_manager = getFragmentManager();
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.setTitle(getApplicationContext().getApplicationInfo().labelRes);
ActionBar.Tab tab_jobList = actionBar.newTab().setText(R.string.stringJobs);
tab_jobList.setIcon(R.drawable.text_list_white);
actionBar.addTab(tab_jobList.setTabListener(new MyTabsListener<JobListLV>(this, "jobList", JobListLV.class, getFragmentManager())));
actionBar.addTab(tab_trends.setTabListener(new MyTabsListener<TrendsPagerHolder>(this, "trendsPagerHolder", TrendsPagerHolder.class, getFragmentManager())));
}
Here's the inner class that has the TabListener:
public MyTabsListener(Activity activity, String tag, Class<T> clz, Bundle args, FragmentManager fragmentManager)
{
mActivity = activity;
mTag = tag;
mClass = clz;
mArgs = args;
fm = fragmentManager;
// Check to see if we already have a fragment for this tab, probably
// from a previously saved state. If so, deactivate it, because our
// initial state is that a tab isn't shown.
mFragment = mActivity.getFragmentManager().findFragmentByTag(mTag);
Log.e("mFragment constructor", "mFragment = " + mFragment);
fragmentTrendsPagerHolder = (TrendsPagerHolder) mActivity.getFragmentManager().findFragmentByTag("trendsPagerHolder");
if (mFragment != null && !mFragment.isDetached())
{
FragmentTransaction ft = mActivity.getFragmentManager().beginTransaction();
if (fragmentTrendsPagerHolder != mFragment)
{
ft.hide(mFragment);
ft.commit();
}
}
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft)
{
displayTab(tab, ft);
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft)
{
if (mFragment != null)
{
ft.hide(mFragment);
}
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft)
{
displayTab(tab, ft);
}
private void displayTab(Tab tab, FragmentTransaction ft)
{
fragmentJobListDetails = mActivity.getFragmentManager().findFragmentByTag("jobDetails");
if (fragmentJobListDetails != null && !fragmentJobListDetails.isDetached())
{
ft.hide(fragmentJobListDetails);
}
if (mFragment == null || !mFragment.isAdded())
{
mFragment = Fragment.instantiate(mActivity, mClass.getName(), mArgs);
ft.add(android.R.id.content, mFragment, mTag);
}
else
{
System.out.println("mFragment.isAdded() = " + mFragment.isAdded());
Log.e("mFragment", "mFragment = " + mFragment);
ft.show(mFragment);
}
}
}// end MyTabsListener
Any suggestions to solve this issue?
Thanks.

Call ft.commit() after ft.show(). So it should be like this:
private void displayTab(Tab tab)
{
FragmentTransaction ft = mActivity.getFragmentManager().beginTransaction();
fragmentJobListDetails = mActivity.getFragmentManager().findFragmentByTag("jobDetails");
if (fragmentJobListDetails != null && !fragmentJobListDetails.isDetached())
{
ft.hide(fragmentJobListDetails);
}
if (mFragment == null || !mFragment.isAdded())
{
mFragment = Fragment.instantiate(mActivity, mClass.getName(), mArgs);
ft.add(android.R.id.content, mFragment, mTag);
}
else
{
System.out.println("mFragment.isAdded() = " + mFragment.isAdded());
Log.e("mFragment", "mFragment = " + mFragment);
ft.show(mFragment);
}
ft.commit();
}
}// end MyTabsListener
Also, create a new fragment transaction to handle the possible transactions for the displayTab method.

Hiding/Showing SherlockFragments in ActionBar.TabListener Class, content is empty

I have an app built using TabBarSherlock and the Support library to add ActionBar support to pre 3.0 devices. I can't remember what tutorial I followed to create the Tabs and the Listener but I have the following code.
Firstly creating the Tabs (Inside a SherlockFragmentActivity):
ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayShowTitleEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
/*--------Setup News Tab--------*/
Tab tab1 = actionBar.newTab()
.setText("News")
.setTabListener(new TabListener<TabFragment>(
this, "tab1", TabFragment.class));
Bundle newsBundle = new Bundle();
newsBundle.putInt("news_id", newsID);
tab1.setTag(newsBundle);
actionBar.addTab(tab1);
/*------------------------------*/
// This is repeated 3 more times to total 4 Tabs.
Then I have a classCalled TabListener which is used in each of these Tabs to detect when they have been selected.
public class TabListener<T extends Fragment> implements ActionBar.TabListener{
private TabFragment mFragment;
private final Activity mActivity;
private final String mTag;
private final Class<T> mClass;
public TabListener(Activity activity, String tag, Class<T> clz) {
mActivity = activity;
mTag = tag;
mClass = clz;
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Check if the fragment is already initialised
if (mFragment == null) {
Log.v("FRAGMENT", "FRAGMENT NEEDS TO BE CREATED");
mFragment = (TabFragment) Fragment.instantiate(mActivity, mClass.getName(), (Bundle)tab.getTag());
ft.add(android.R.id.content, mFragment, mTag);
} else {
Log.v("FRAGMENT", "FRAGMENT ALREADY CREATED");
ft.show(mFragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
ft.hide(mFragment);
}
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
}
With the class TabFragment containing a ViewPager for each Tab. My issue is that when selecting a Tab other than the first one the content inside the Fragment does not show. From the logs in place when the Fragment is initialised I can tell the views are being created just not being shown, it's just a blank area showing the background.

Instead of using show() and hide(), use attach() and detach(). Using show/hide does not remove the view hierarchy from the screen, simply hides it, so there might be issues related to that.

You are not detaching fragment rather you are just hiding it. so you should detach it so that other fragment should be attached in your onTabUnSelected.
FragmentManager will automatically restore whatever fragment (and history) was currently displayed upon a configuration change. Call findFragmentByTag to see if an instance of the target fragment already exists before creating and attaching a new instance.
Example:
public void onTabSelected(Tab tab, FragmentTransaction ft) {
SherlockFragment preInitializedFragment = (SherlockFragment) mActivity.getSupportFragmentManager().findFragmentByTag(mTag);
// Check if the fragment is already initialized
if (mFragment == null && preInitializedFragment == null) {
// If not, instantiate and add it to the activity
mFragment = (SherlockFragment) SherlockFragment.instantiate(mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment, mTag);
} else if (mFragment != null) {
// If it exists, simply attach it in order to show it
ft.attach(mFragment);
} else if (preInitializedFragment != null) {
ft.attach(preInitializedFragment);
mFragment = preInitializedFragment;
}
}
and you onTabUnSelected should be like this
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(mFragment);
}
}

Content is empty on tab bar then write below code
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(actionBar.NAVIGATION_MODE_STANDARD);

nested fragments at ActionBar switching

I use ActionBar and use inner TabListener in the Activity:
public static class TabListener<T extends Fragment>
implements ActionBar.TabListener{
private final Activity myActivity;
private final String myTag;
private final Class<T> myClass;
public TabListener(Activity activity, String tag, Class<T> cls) {
myActivity = activity;
myTag = tag;
myClass = cls;
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
Fragment myFragment = myActivity.getFragmentManager().findFragmentByTag(myTag);
// Check if the fragment is already initialized
if (myFragment == null) {
// If not, instantiate and add it to the activity
myFragment = Fragment.instantiate(myActivity, myClass.getName());
myActivity.setTitle( myClass.getName());
ft.add(android.R.id.content, myFragment, myTag);
} else {
// If it exists, simply attach it in order to show it
myActivity.setTitle( myFragment.getClass().getName());
ft.attach(myFragment);
}
Log.i("current fragment", myFragment.getClass().toString());
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
Fragment myFragment = myActivity.getFragmentManager().findFragmentByTag(myTag);
if (myFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(myFragment);
}
}
}
I need to switch another Fragment at the current tab from DialogFragment . I do it in common way like this:
Fragment newFragment = new ContactsArchiveFragment();
fragmentTransaction.replace(android.R.id.content, newFragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
But when I switch to another tab, my current Fragment(which was switched to) is not detached and displays above. How can I solve this?

Try This..
public void addFragment(Fragment fragment, boolean addToBackStack,
int transition) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(android.R.id.content, fragment);
ft.setTransition(transition);
if (addToBackStack)
ft.addToBackStack(null);
ft.commit();
}
You can use true first time, then change it to false
addFragment(newfragment, true, FragmentTransaction.TRANSIT_NONE);

I solved my issue, using this. Here's the solution:
public static class TabListener<T extends Fragment>
implements ActionBar.TabListener{
private final Activity myActivity;
private final String myTag;
private final Class<T> myClass;
private Fragment mFragment;
public TabListener(Activity activity, String tag, Class<T> cls) {
myActivity = activity;
myTag = tag;
myClass = cls;
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Fragment myFragment = myActivity.getFragmentManager().findFragmentByTag(myTag);
Fragment preInitializedFragment = (Fragment) myActivity.getFragmentManager().findFragmentByTag(myTag);
if (preInitializedFragment == null) {
mFragment = (Fragment) Fragment.instantiate(myActivity, myClass.getName());
ft.add(android.R.id.content, mFragment, myTag);
} else {
ft.attach(preInitializedFragment);
}
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
Fragment preInitializedFragment = myActivity.getFragmentManager().findFragmentByTag(myTag);
if (preInitializedFragment != null) {
ft.detach(preInitializedFragment);
} else if (mFragment != null) {
ft.detach(mFragment);
}
}
}

Replacing Fragment in tab, changes all tabs

EDIT
I edited the previous question, wich i solved. Thanks a lot for the replies.
I have a gui with 3 tabs (News, Strategy and History), in one of them (News) i load an ExpandableListView and when the user clicks in one of the items from the list, it loads another fragment containg details from the selected item. I managed to replace the fragment in that tab with another fragment, using this code:
CategoryTab categories = new CategoryTab();//Fragment 2
FragmentManager manager = activity.getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(this.getId(), categories, "News");
//transaction.replace(android.R.id.content, categories, "News");
transaction.addToBackStack(null);
transaction.commit();
When the seconds fragment loads in the News tab, all the other tabs shows that fragment. I'm using this listener to manage tab navigation
public static class TabListener<T extends Fragment> implements ActionBar.TabListener {
private final Activity mActivity;
private final String mTag;
private final Class<T> mClass;
private final Bundle mArgs;
private Fragment mFragment;
public TabListener(Activity activity, String tag, Class<T> clz) {
this(activity, tag, clz, null);
}
public TabListener(Activity activity, String tag, Class<T> clz, Bundle args) {
mActivity = activity;
mTag = tag;
mClass = clz;
mArgs = args;
// Check to see if we already have a fragment for this tab, probably
// from a previously saved state. If so, deactivate it, because our
// initial state is that a tab isn't shown.
mFragment = mActivity.getFragmentManager().findFragmentByTag(mTag);
if (mFragment != null && !mFragment.isDetached()) {
FragmentTransaction ft = mActivity.getFragmentManager().beginTransaction();
ft.detach(mFragment);
ft.commit();
}
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
if (mFragment == null) {
mFragment = Fragment.instantiate(mActivity, mClass.getName(), mArgs);
ft.add(android.R.id.content, mFragment, mTag);
} else {
ft.attach(mFragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
ft.detach(mFragment);
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
Toast.makeText(mActivity, "Reselected!", Toast.LENGTH_SHORT).show();
}
}
My question is ¿why all the tabs shows the same fragment when the replacement is done? and ¿how can i simulate a back button with the icon provided in the action bar, to load again fragment 1 in News Tab?
Any help will be appreciated
PD: Sorry for my english

Make sure you call getActivity() in or after onActivityCreated, as before then it will return null.
The Fragment will be attached to a null activity until onActivityCreated... that is, if you call getActivity() in onCreate or onCreateView, it will return null because the Activity hasn't been created yet. So make sure you have all of your calls to getActivity() in or after onActivityCreated

Custom Back Stack for each Fragment in TabHost in Android

Since the TabActivity is deprecated I tried to replace it with Fragments which has been already mentioned in developer android website. But as you guys already know there was an issue about replacing tabs with fragments, since there will be only one activity ,which is Fragment Activity, there is no back stack for each of the fragments and as you can see in the other SO questions most of the developers were saying that you need to manage your own custom back stack as a solution.
I have created and implemented my own custom back stack as you can see below, it works perfect I can track each fragment in each tab.
Tab1
Fragment1 > Fragment2 > Fragment3
Tab2
Fragment5 > Fragment6
According to navigation above, if I navigate from Fragment1 through Fragment 3 and After that If I change the tab to Tab2 to and come back to Tab1, I can still see the Fragment3 and I can even navigate back to Fragment1 with my custom back stack.
But the issue is, When I come back to Tab1 and see the Fragment3, the Fragment3 is re-created and I can not see the changes as I left behind before I change the tab to Tab2.
Here is my Custom back stack;
public static HashMap<String, Stack<Fragment>> customBackStack;
public static Stack<Fragment> simpleStack;
public static Stack<Fragment> contactStack;
public static Stack<Fragment> customStack;
public static Stack<Fragment> throttleStack;
public static Stack<Fragment> homeStack;
customBackStack = new HashMap<String, Stack<Fragment>>();
homeStack = new Stack<Fragment>();
simpleStack = new Stack<Fragment>();
contactStack = new Stack<Fragment>();
customStack = new Stack<Fragment>();
throttleStack = new Stack<Fragment>();
customBackStack.put("home", homeStack);
customBackStack.put("simple", simpleStack);
customBackStack.put("contacts", contactStack);
customBackStack.put("custom", customStack);
customBackStack.put("throttle", throttleStack);
And here is onTabChanged method;
public void onTabChanged(String tabId) {
TabInfo newTab = mTabs.get(tabId);
if (mLastTab != newTab) {
FragmentTransaction ft = mActivity.getSupportFragmentManager().beginTransaction();
if (mLastTab != null) {
if (mLastTab.fragment != null) {
ft.detach(mLastTab.fragment);
}
}
if (newTab != null) {
if (newTab.fragment == null) {
if (!customBackStack.get(tabId).isEmpty()) {
Fragment fragment = customBackStack.get(tabId).pop();
customBackStack.get(tabId).push(fragment);
ft.replace(mContainerId, fragment);
}
} else {
if (!customBackStack.get(tabId).isEmpty()) {
Fragment fragment = customBackStack.get(tabId).pop();
customBackStack.get(tabId).push(fragment);
ft.replace(mContainerId, fragment);
}
}
}
mLastTab = newTab;
ft.commit();
mActivity.getSupportFragmentManager().executePendingTransactions();
}
}
And here is onBackPressed;
public void onBackPressed() {
Stack<Fragment> stack = customBackStack.get(mTabHost.getCurrentTabTag());
if (stack.isEmpty()) {
super.onBackPressed();
} else {
Fragment fragment = stack.pop();
if (fragment.isVisible()) {
if (stack.isEmpty()) {
super.onBackPressed();
} else {
Fragment frg = stack.pop();
customBackStack.get(mTabHost.getCurrentTabTag()).push(frg);
transaction = getSupportFragmentManager().beginTransaction();
transaction.setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right,
R.anim.slide_in_right, R.anim.slide_out_left);
transaction.replace(R.id.realtabcontent, frg).commit();
}
} else {
getSupportFragmentManager().beginTransaction().replace(R.id.realtabcontent, fragment).commit();
}
}
}
As a result, custom back stack works fine except the last fragment before changing the tab is getting re-created after coming back to the tab, its not resuming as like in tab activity.
Any idea how to solve it ?
EDIT
You can find my sample Application here as a solution regarding to this issue.
GitHub

I modified googles sample tablistener to following:
public static class TabListener<T extends SherlockFragment> implements ActionBar.TabListener {
private final SherlockFragmentActivity mActivity;
private final String mTag;
private final Class<T> mClass;
private final Bundle mArgs;
public SherlockFragment mFragment;
private final Stack<SherlockFragment> mStack;
public TabListener(SherlockFragmentActivity activity, String tag, Class<T> clz) {
this(activity, tag, clz, null, null);
}
public TabListener(SherlockFragmentActivity activity, String tag, Class<T> clz, Bundle args, Stack<SherlockFragment> stack) {
mActivity = activity;
mTag = tag;
mClass = clz;
mArgs = args;
mStack = stack;
// Check to see if we already have a fragment for this tab, probably
// from a previously saved state. If so, deactivate it, because our
// initial state is that a tab isn't shown.
mFragment = (SherlockFragment) mActivity.getSupportFragmentManager().findFragmentByTag(mTag);
if (mFragment != null && !mFragment.isDetached()) {
FragmentTransaction ft = mActivity.getSupportFragmentManager().beginTransaction();
ft.detach(mFragment);
ft.commit();
}
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// we need to reattach ALL fragments thats in the custom stack, if we don't we'll have problems with setCustomAnimation for fragments.
if (mFragment == null) {
mFragment = (SherlockFragment) SherlockFragment.instantiate(mActivity, mClass.getName(), mArgs);
ft.replace(android.R.id.content, mFragment, mTag);
} else {
ft.attach(mFragment);
}
if(mStack != null) {
for(SherlockFragment fragment: mStack) {
ft.attach(fragment);
}
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
ft.detach(mFragment);
}
if(mStack != null) {
for(SherlockFragment fragment: mStack) {
if(fragment!= null && !fragment.isDetached()) {
ft.detach(fragment);
}
}
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
}
And the activity onKeyDown methode I override to following:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
int index = getSupportActionBar().getSelectedNavigationIndex();
Stack<SherlockFragment> stack = null;
SherlockFragment fragment = null;
String rootTag = null;
switch(index) {
case 0:
stack = mWatersTabListener.mStack;
fragment = mWatersTabListener.mFragment;
rootTag = mWatersTabListener.mTag;
break;
case 1:
stack = mHarborTabListener.mStack;
fragment = mHarborTabListener.mFragment;
rootTag = mHarborTabListener.mTag;
break;
}
if(stack.isEmpty()) {
return super.onKeyDown(keyCode, event);
} else {
SherlockFragment topFragment = stack.pop();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
ft.setCustomAnimations(R.anim.fragment_slide_right_enter,
R.anim.fragment_slide_right_exit);
if(topFragment != null && !topFragment.isDetached()) {
ft.detach(topFragment);
}
if(stack.isEmpty()) {
ft.replace(android.R.id.content, fragment, rootTag);
ft.commit();
return true;
} else {
SherlockFragment nextFragment = stack.peek();
ft.replace(android.R.id.content, nextFragment);
ft.commit();
return true;
}
}
}
return super.onKeyDown(keyCode, event);
}
The important things to take note of is that you have to attach all fragments in your custom stack when selected and you have to detach all as well when unselected. If there is problem with understanding the code snippets just ask.