I have three tabs with a pageviewer and actionbar bar. When I try to switch back to a tab that was already selected, no data is shown, but the logcat indicates that data was pulled from the server and add in the arraylist.
Any suggestions as to why the data will not show now? I have done extensive research and still fail to understand what is happening.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_tabs);
viewPager = (ViewPager) findViewById(R.id.pager);
Log.v("Main-onCreate-viewPager", viewPager.toString());
actionBar = getSupportActionBar();
mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Adding Tabs
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name).setTabListener(this));
Log.v("Main", "tab added");
}
/**
* on swiping the viewpager make respective tab selected
**/
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
Log.v("onPageScrolled-position", Integer.toString(position));
Log.v("onPageScrolled-position", Float.toString(positionOffset));
Log.v("onPageScrolled-position", Integer.toString(positionOffsetPixels));
}
public void onPageSelected(int position) {
// on changing the page
// make respected tab selected
Log.v("onPageSelected", "onPageSelected");
actionBar.setSelectedNavigationItem(position);
Log.v("onPageSelected-position", Integer.toString(position));
}
public void onPageScrollStateChanged(int state) {
Log.v("StateChanged", "OnPageScrollStateChanged");
Log.v("statechanged-state", Integer.toString(state));
}
});
}
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
Log.v("Main", "Tab REselected");
Log.v("onTabReselected", tab.toString());
Log.v("onTabReselected", ft.toString());
if(tab.getPosition() == 0){
Log.v("onTabReselected", "ImagesFragment");
Fragment frag;
FragmentManager fm1 = Main.this.getSupportFragmentManager();
FragmentTransaction ft1 = fm1.beginTransaction();
frag = new ImagesFragment();
//frag = new FeaturesFragment();
ft1.replace(R.id.pager, frag);
ft1.commit();
frag.setUserVisibleHint(true);
}
if (tab.getPosition() == 1) {
Log.v("onTabReselected", "FeaturesFragment");
Fragment frag;
FragmentManager fm1 = Main.this.getSupportFragmentManager();
FragmentTransaction ft1 = fm1.beginTransaction();
frag = new FeaturesFragment();
ft1.replace(R.id.pager, frag);
ft1.commit();
frag.setUserVisibleHint(true);
}
if (tab.getPosition() == 2) {
Log.v("onTabReselected", "OptionsFragment");
Fragment frag;
FragmentManager fm1 = Main.this.getSupportFragmentManager();
FragmentTransaction ft1 = fm1.beginTransaction();
frag = new OptionsFragment();
ft1.replace(R.id.pager, frag);
ft1.commit();
frag.setUserVisibleHint(true);
}
}
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
// on tab selected
// show respected fragment view
Log.v("onTabSelected", tab.toString());
Log.v("onTabSelected", ft.toString());
Log.v("tab position1", Integer.toString(tab.getPosition()));
viewPager.setOffscreenPageLimit(0);
//viewPager.setCurrentItem(tab.getPosition()); //null pointer exception here
tab.select(); //no null pointer exception, but no show data when swiping tabs
Log.v("onTabSelected", tab.toString());
Log.v("tab position", Integer.toString(tab.getPosition()));
if (tab.getPosition() == 0) {
Fragment frag;
FragmentManager fm1 = Main.this.getSupportFragmentManager();
FragmentTransaction ft1 = fm1.beginTransaction();
frag = new ImagesFragment();
ft1.replace(R.id.pager, frag);
ft1.commit();
frag.setUserVisibleHint(true);
}
if (tab.getPosition() == 1) {
Fragment frag;
FragmentManager fm1 = Main.this.getSupportFragmentManager();
FragmentTransaction ft1 = fm1.beginTransaction();
frag = new FeaturesFragment();
ft1.replace(R.id.pager, frag);
ft1.commit();
frag.setUserVisibleHint(true);
}
if (tab.getPosition() == 2) {
Fragment frag;
FragmentManager fm1 = Main.this.getSupportFragmentManager();
FragmentTransaction ft1 = fm1.beginTransaction();
frag = new OptionsFragment();
ft1.replace(R.id.pager, frag);
ft1.commit();
frag.setUserVisibleHint(true);
}
}
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
Log.v("Main", "Tab UNselected");
Log.v("onTabUnselected", tab.toString());
Log.v("onTabUnselected", ft.toString());
}
public class TabsPagerAdapter extends FragmentStatePagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int index) {
Log.v("index", Integer.toString(index));
switch (index) {
case 0:
Log.v("TabsPagerAdapter", "case 0: ImagesFragment");
return new ImagesFragment();
case 1:
Log.v("TabsPagerAdapter", "case 1: FeaturesFragment");
return new FeaturesFragment();
case 2:
Log.v("TabsPagerAdapter", "case 2: OptionsFragment");
return new OptionsFragment();
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 3;
}
}
Use FragmentStatePagerAdapter in place of TabsPagerAdapter.
This may help you i also had this problem i have 4 tabs and switching them re creates the view, after setting adapter use this code,
viewPager.setAdapter(mAdapter);
viewPager.setOffscreenPageLimit(5); //this one.!
Any number of limit you can have but better to have low numbers because of memory customization, use it inside oncreate() method(if Activity).
Related
When i change tab of Bottom Bar for example when the home tab is selected and when i change the tab and select category tab in first time load data and it is not problem but when select again home tab again reload fragment and load data again.
how to resolve this problem and save state fragment.
My code:
bottomBar.setOnTabSelectListener(new OnTabSelectListener() {
#Override
public void onTabSelected(int tabId) {
displayFragment(tabId);
}
});
private void displayFragment(int id) {
Fragment selectedFragment = null;
switch (id) {
case R.id.tab_home:
selectedFragment = HomeFragment.getInstance();
break;
case R.id.tab_category:
selectedFragment = CategoryFragment.getInstace();
break;
}
if (selectedFragment != null) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.contentContainer, selectedFragment);
transaction.commit();
}
}
There are multiple ways you can handle preserving and updating your fragments data throughout its life cycle. I would look into the lifecycle of activity fragments to better grasp what applies to your context. From 30k feet, after you call .replace() the fragment's override onCreateView() should fire, here you can handle your update logic.
As I mentioned, context is big here. If you end up changing your transaction logic, it could impact the life cycle of your fragments. For example, if you were hiding/showing your fragments, using the override onHidden() or onResume() could be a better solution.
In addition, you also should consider how your navigation logic impacts and interacts with your activity's/fragment's backstack. In your current logic, you're creating a new instance of the fragment each time a tab is selected.
This is answer my question :
public class MainActivity extends AppCompatActivity {
FeedFragment feedFragment;
PublishFragment publishFragment;
ServicesFragment servicesFragment;
SearchFragment searchFragment;
ProfileFragment profileFragment;
FragmentTransaction ft;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
BottomBar bottomBar = (BottomBar) findViewById(R.id.bottomBar);
feedFragment = new FeedFragment();
publishFragment = new PublishFragment();
servicesFragment = new ServicesFragment();
searchFragment = new SearchFragment();
profileFragment = new ProfileFragment();
bottomBar.setOnTabSelectListener(new OnTabSelectListener() {
#Override
public void onTabSelected(#IdRes int tabId) {
if (tabId == R.id.feed_icon) {
GeneralUtils.logPrint("feed");
ft = getSupportFragmentManager().beginTransaction();
if (feedFragment.isAdded()) {
ft.show(feedFragment);
} else {
ft.add(R.id.fragment_container, feedFragment);
}
hideFragment(ft,publishFragment);
hideFragment(ft, servicesFragment);
hideFragment(ft,searchFragment);
hideFragment(ft,profileFragment);
ft.commit();
}
if (tabId == R.id.publish_icon) {
GeneralUtils.logPrint("publish");
ft = getSupportFragmentManager().beginTransaction();
if (publishFragment.isAdded()) {
ft.show(publishFragment);
} else {
ft.add(R.id.fragment_container, publishFragment);
}
hideFragment(ft,feedFragment);
hideFragment(ft, servicesFragment);
hideFragment(ft,searchFragment);
hideFragment(ft,profileFragment);
ft.commit();
}
if (tabId == R.id.services_icon) {
GeneralUtils.logPrint("services");
ft = getSupportFragmentManager().beginTransaction();
if (servicesFragment.isAdded()) {
ft.show(servicesFragment);
} else {
ft.add(R.id.fragment_container, servicesFragment);
}
hideFragment(ft,feedFragment);
hideFragment(ft, publishFragment);
hideFragment(ft,searchFragment);
hideFragment(ft,profileFragment);
ft.commit();
}
if (tabId == R.id.search_icon) {
GeneralUtils.logPrint("search");
ft = getSupportFragmentManager().beginTransaction();
if (searchFragment.isAdded()) {
ft.show(searchFragment);
} else {
ft.add(R.id.fragment_container, searchFragment);
}
hideFragment(ft,feedFragment);
hideFragment(ft,publishFragment);
hideFragment(ft,servicesFragment);
hideFragment(ft,profileFragment);
ft.commit();
}
if (tabId == R.id.profile_icon) {
GeneralUtils.logPrint("profile");
ft = getSupportFragmentManager().beginTransaction();
if (profileFragment.isAdded()) {
ft.show(profileFragment);
} else {
ft.add(R.id.fragment_container, profileFragment);
}
hideFragment(ft,feedFragment);
hideFragment(ft, publishFragment);
hideFragment(ft,servicesFragment);
hideFragment(ft,searchFragment);
ft.commit();
}
}
});
}
private void hideFragment(FragmentTransaction ft, Fragment f) {
if (f.isAdded()) {
ft.hide(f);
}
}
}
I want to create an activity that can display any number of tabs, without creating an activity for each tab.
Is it possible?
The only way I saw creating tabs included creating an activity for each one.
You can try as follows ,
Extend your activity from ActionBarActivity and add required number of tabs programmatically ,
ActionBar.TabListener tabListener;
mactionBar = getActionBar();
mactionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
tabListener=new ActionBar.TabListener() {
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
displayTabs(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
displayTabs(tab.getPosition());
}
};
mactionBar.addTab(mactionBar.newTab().setText(<any text>).setTabListener(tabListener));
//call the same method for required number of tabs
Call the same fragment for each tab click
private void displayTabs(int position)
{
Fragment fragment = null;
switch (position) {
case 0:
fragment = new YourFragment();
break;
case 1:
fragment = new YourFragment();
break;
// same for required numder of cases
default:
break;
}
if (fragment != null)
{
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(<container id>, fragment).commit();
}
}
How can I attach existing fragment, when change back tab in ActionBar.NAVIGATION_MODE_TABS?
class MyTabsListener implements ActionBar.TabListener {
public Fragment fragment;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.fragment_container, fragment);
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.detach(fragment);
}
}
You can verify if your fragment was loaded previously in the fragment stack. Also could store all your used fragments to reuse it
public void setFragment(Fragment fragmentInstance) {
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
Fragment oldFragmentInstance = fragmentManager
.findFragmentById(R.id.curr_fragment);
boolean onlyAttach = false;
List<Fragment> prevFragments = getSupportFragmentManager()
.getFragments();
for (Fragment fragment : prevFragments) {
if (fragment == null) {
continue;
}
if (fragment.getClass().equals(fragmentInstance.getClass())) {
onlyAttach = true;
fragmentInstance = fragment;
break;
}
}
fragmentTransaction.detach(oldFragmentInstance);
if (onlyAttach) {
fragmentTransaction.attach(fragmentInstance);
} else {
fragmentTransaction.replace(R.id.curr_fragment,
fragmentInstance);
fragmentTransaction.addToBackStack(null);
}
try {
fragmentTransaction.commit();
}
}
Hope this helps
So i'm getting this annoying problem. I'm pretty noob when it comes to android, so any help would be nice.
This is my MainActivity which seems to be crashing according to LogCat.
The app i'm trying to create must pull data from XML data, which i'm trying to get. Then from this data it must set the tabs name (that's what i'm trying to do).
public class MainActivity extends SherlockActivity {
private String uniqeAppId;
private ArrayList<StartupInfo> info;
private String ChannelTab;
private String VicinityTab;
private String CustomTab;
private String TrackingTab;
private String MoreTab;
public static Context appContext;
private DownloadXmlTask downloadxml = new DownloadXmlTask(this);
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
info = new ArrayList<StartupInfo>();
downloadxml.loadPage();
appContext = getApplicationContext();
ActionBar actionbar = getSupportActionBar();
actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionbar.setTitle(uniqeAppId);
ActionBar.Tab Frag1 = actionbar.newTab().setText(ChannelTab);
ActionBar.Tab Frag2 = actionbar.newTab().setText(VicinityTab);
ActionBar.Tab Frag3 = actionbar.newTab().setText(CustomTab);
ActionBar.Tab Frag4 = actionbar.newTab().setText(TrackingTab);
ActionBar.Tab Frag5 = actionbar.newTab().setText(MoreTab);
Fragment Fragment1 = new Channeltab();
Fragment Fragment2 = new Vicinitytab();
Fragment Fragment3 = new Customtab();
Fragment Fragment4 = new Trackingtab();
Fragment Fragment5 = new Moretab();
Frag1.setTabListener(new MyTabListener(Fragment1));
Frag2.setTabListener(new MyTabListener(Fragment2));
Frag3.setTabListener(new MyTabListener(Fragment3));
Frag4.setTabListener(new MyTabListener(Fragment4));
Frag5.setTabListener(new MyTabListener(Fragment5));
actionbar.addTab(Frag1);
actionbar.addTab(Frag2);
actionbar.addTab(Frag3);
actionbar.addTab(Frag4);
actionbar.addTab(Frag5);
}
public void GetTextForTabs(ArrayList<StartupInfo> info2) {
this.info = info2;
StartupInfo info3 = info.get(0);
this.ChannelTab = info3.getChannelTab();
this.VicinityTab = info3.getVicinityTab();
this.CustomTab = info3.getCustomTab();
this.TrackingTab = info3.getTrackingTab();
this.MoreTab = info3.getMoreTab();
}
#Override
public void onStart() {
super.onStart();
}
public void setInfo(ArrayList<StartupInfo> info) {
this.info = info;
}
public void alert(String msg) {
Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_LONG).show();
}
public class MyTabListener implements ActionBar.TabListener {
public Fragment fragment;
public MyTabListener(Fragment fragment) {
this.fragment = fragment;
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.fragment_container, fragment);
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.remove(fragment);
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
}
}
Then the LogCat:
It seems to be the TabListener. But I don't understand why. It wasn't doing that earlier. It was when i tried to add data it started to crash. Can anyone help me here ?
You have a null pointer exception at line 111 of your activity (in onTabSelected). It looks as though the null reference is probably to "fragment". Look at the section on "Performing fragment transactions":
http://developer.android.com/guide/components/fragments.html
This code will not fit your program exactly, but it gives you the general idea. You need to begin, do your add/replace/why and then commit.
By the by, since you are using ActionBarSherlock why not use the Support library so as to be able to support older versions of Android ?
Here is a simple example (it contains some superfluous stuff that you don't need) that might help:
public class ExtraContent extends SherlockFragmentActivity {
// Declare Tab Variable
com.actionbarsherlock.app.ActionBar.Tab tab;
boolean mDebugLog = false;
String mDebugTag="ian_";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//mDebugLog = true;
debugLog("ExtraContent onCreate" );
// Create the actionbar
com.actionbarsherlock.app.ActionBar bar = getSupportActionBar();
// Show Actionbar Home Icon (as normal)
bar.setDisplayShowHomeEnabled(true);
// Show Actionbar Title (as normal)
bar.setDisplayShowTitleEnabled(true);
// Create Actionbar Tabs
bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//enable home ...
bar.setDisplayHomeAsUpEnabled(true); // ?
bar.setHomeButtonEnabled(true); // this is the one that enables home navigation
//ib18 view for fragments ...
setContentView(R.layout.extra_content);
//create the fragment we want to use for display content
Fragment ExtraLogin = new ExtraLogIn();
// Create First Tab
ActionBar.Tab tab0 = bar.newTab();
tab0 = bar.newTab();
tab0.setText("Unlock");
tab0.setTabListener(new TabListener<ExtraTab0>(this, "tab0",ExtraTab0.class, null));
bar.addTab(tab0);
// Create Second Tab
ActionBar.Tab tab1 = bar.newTab();
tab1 = bar.newTab();
tab1.setText("Level 1");
tab1.setTabListener(new TabListener<ExtraTab1>(this, "tab1",ExtraTab1.class, null));
bar.addTab(tab1);
// Create Third Tab
ActionBar.Tab tab2 = bar.newTab();
tab2 = bar.newTab();
tab2.setText("Level 2");
tab2.setTabListener(new TabListener<ExtraTab2>(this, "tab2",ExtraTab2.class, null));
bar.addTab(tab2);
if (savedInstanceState != null) { //if there is a saved bundle use it ...
bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
}
else {
//ib18 savedInstanceState null so fti so start Login frag ...
FragmentManager fm = getSupportFragmentManager();
fm.beginTransaction().replace(R.id.fb, ExtraLogin, "ExtraLogin").commit();
}
}
public boolean onMenuItemSelected(int featureId, MenuItem item) {
debugLog("ExtraContent onMenuItemSelected" );
int itemId = item.getItemId();
switch (itemId) {
case android.R.id.home:
// app icon in action bar clicked; go home
Intent intent = new Intent(this, QuizLaunch.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
debugLog("ExtraContent onSaveInstanceState");
super.onSaveInstanceState(outState);
outState.putInt("tab", getSupportActionBar().getSelectedNavigationIndex());
}
public class TabListener<T extends Fragment> implements ActionBar.TabListener{
private final FragmentActivity mActivity;
private final String mTag;
private final Class<T> mClass;
private final Bundle mArgs;
private Fragment mFragment;
public TabListener (FragmentActivity activity, String tag, Class<T> clz,
Bundle args) {
mActivity = activity;
mTag = tag;
mClass = clz;
mArgs = args;
debugLog("ExtraContent TabListener" );
FragmentTransaction ft = mActivity.getSupportFragmentManager().beginTransaction();
// 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.getSupportFragmentManager().findFragmentByTag(mTag);
//
if (mFragment != null && !mFragment.isDetached()) {
ft.detach(mFragment);
}
ft.commit();
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
debugLog("ExtraContent onTabSelected");
ft = mActivity.getSupportFragmentManager()
.beginTransaction();
if (mFragment == null) {
mFragment = Fragment.instantiate(mActivity, mClass.getName(),mArgs);
debugLog("adding fragment "+mTag );
ft.add(R.id.tab, mFragment, mTag); //ib18 add to "tab" holder
ft.show(mFragment); //ib1.6 show fragment ...
ft.commit();
} else {
debugLog("attaching fragment "+mTag );
ft.attach(mFragment);
ft.show(mFragment); //ib1.6 show fragment ...
ft.commit();
}
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
debugLog("ExtraContent onTabUnSelected");
ft = mActivity.getSupportFragmentManager()
.beginTransaction();
if (mFragment != null) {
debugLog("hide and detach fragment "+mFragment );
ft.hide(mFragment); //ib1.6 hide fragment ...
ft.detach(mFragment);
ft.commitAllowingStateLoss();
}
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
debugLog("ExtraContent onTabReSelected");
}
}
void debugLog(String message) {
if (mDebugLog)
Log.d(mDebugTag, message);
}
}
I have a Fragment Activity which holds three fragments.
public class MainActivity extends SherlockFragmentActivity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActionBar bar = getSupportActionBar();
bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab tab1 = bar.newTab();
ActionBar.Tab tab2 = bar.newTab();
ActionBar.Tab tab3 = bar.newTab();
tab1.setText("");
tab1.setIcon(R.drawable.abs__ic_menu_share_holo_dark);
tab2.setText("");
tab2.setIcon(R.drawable.abs__ic_voice_search);
tab3.setText("");
tab3.setIcon(R.drawable.abs__ic_cab_done_holo_dark);
if (savedInstanceState == null) {
tab1.setTabListener(new MyTabListener());
tab2.setTabListener(new MyTabListener());
tab3.setTabListener(new MyTabListener());
bar.addTab(tab1);
bar.addTab(tab2);
bar.addTab(tab3);
}
}
private class MyTabListener implements ActionBar.TabListener {
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
switch (tab.getPosition()) {
case 0:
FeedsActivity frag = new FeedsActivity();
ft.replace(android.R.id.content, frag);
return;
case 1:
ProfileActivity frag2 = new ProfileActivity();
ft.replace(android.R.id.content, frag2);
return;
case 2:
MyMemoirsActivity frag3 = new MyMemoirsActivity();
ft.replace(android.R.id.content, frag3);
return;
}
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
}
}
And here is first Fragment,
public class FeedsActivity extends SherlockFragment {
public static String[] MainCategory;
public static String[] MainCategoryId;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup group,
Bundle saved) {
setRetainInstance(true);
return inflater.inflate(R.layout.activity_feeds, group, false);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
new GetMainCategory(getActivity()).execute();
}
}
When I select second tab and then select first tab the async task in first fragment is called again.How can I retain state of first fragment so that its view is created once? I have used setRetainInstance(true) but didnt work.
I solved this issue by using show and hide instead of attach and detach.
private class MyTabListener implements ActionBar.TabListener {
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
switch (tab.getPosition()) {
case 0:
if (frag1 == null) {
// If not, instantiate and add it to the activity
frag1 = Fragment.instantiate(getApplicationContext(),
FeedsActivity.class.getName());
ft.add(android.R.id.content, frag1, "Feeds");
} else {
// If it exists, simply attach it in order to show it
ft.show(frag1);
}
return;
case 1:
if (frag2 == null) {
// If not, instantiate and add it to the activity
frag2 = Fragment.instantiate(getApplicationContext(),
ProfileActivity.class.getName());
ft.add(android.R.id.content, frag2, "Profile");
} else {
// If it exists, simply attach it in order to show it
ft.show(frag2);
}
return;
case 2:
if (frag3 == null) {
// If not, instantiate and add it to the activity
frag3 = Fragment.instantiate(getApplicationContext(),
History.class.getName());
ft.add(android.R.id.content, frag3, "History");
} else {
// If it exists, simply attach it in order to show it
ft.show(frag3);
}
return;
}
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
if (frag1 != null) {
// Detach the fragment, because another one is being attached
switch (tab.getPosition()) {
case 0:
ft.hide(frag1);
return;
case 1:
ft.hide(frag2);
return;
case 2:
ft.hide(frag3);
return;
}
}
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
}
The proper way to use TabListener is this :
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Check if the fragment is already initialized
if (mFragment == null) {
// If not, instantiate and add it to the activity
mFragment = Fragment.instantiate(mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment, mTag);
} else {
// If it exists, simply attach it in order to show it
ft.attach(mFragment);
}
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(mFragment);
}
}
#override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
Basically you need to check if that's the first time when your Fragment is being initialised. If not, you should add it to your screen and when the user unselect a tab you should detach the current visible fragment and add the new one. That's the way it should work. You don't need to create a new instance of Fragment everytime user click the tab.