I have an activity which makes use of a FragmentTabHost, so each tab has a fragment inside it. In the first tab, I have 2 nested fragments, one on the top half of the screen, the other on the bottom half. The fragment on the bottom uses a ViewPager to scan through several LinearLayouts. It all works pretty well.
Until you move to another tab, and return to the first. The bottom nested fragment no longer appears, but the one on top does.
Here's some code demonstrating my usage:
This is how I'm using my main activity:
public class MainActivity extends SherlockFragmentActivity
{
private FragmentTabHost mTabHost;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity_layout_vert);
mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);
mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
mTabHost.addTab(mTabHost.newTabSpec("TAB1").setIndicator("", getResources().getDrawable(R.drawable.tab1_selector)), Tab1Fragment.class, null);
mTabHost.addTab(mTabHost.newTabSpec("TAB2").setIndicator("", getResources().getDrawable(R.drawable.tab2_selector)), Tab2Fragment.class, null);
}
}
Here's how I'm using the fragment for tab1:
public class Tab1Fragment extends SherlockFragment
{
private NestedFragment1 mNestedFrag1 = null;
private NestedFragment2 mNestedFrag2 = null;
#Override
public void onCreate(Bundle inSavedInstanceState)
{
super.onCreate(inSavedInstanceState);
mNestedFrag1 = new NestedFragment1();
mNestedFrag2 = new NestedFragment2();
FragmentManager fragManager = getChildFragmentManager();
FragmentTransaction fragTransaction = fragManager.beginTransaction();
fragTransaction.add(R.id.nested_frag1_container, mNestedFrag1, "Frag1");
fragTransaction.add(R.id.nested_frag2_container, mNestedFrag2, "Frag2");
fragTransaction.commit();
}
#Override
public void onDestroy()
{
FragmentManager fragManager = getChildFragmentManager();
FragmentTransaction fragTransaction = fragManager.beginTransaction();
fragTransaction.remove(mNestedFrag1);
fragTransaction.remove(mNestedFrag2);
fragTransaction.commit();
}
}
And here is how I'm using the 2nd nested fragment (the one that disappears):
public class NestedFragment2 extends SherlockFragment
{
private MyPageAdapter mPageAdapter;
private ViewPager mViewPager;
#Override
public void onCreate(Bundle inSavedInstanceState)
{
super.onCreate(inSavedInstanceState);
mPageAdapter = new MyPageAdapter();
}
#Override
public void onDestroy()
{
super.onDestroy();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View toReturn = inflater.inflate(R.layout.nested_fragment1_layout_top, container, false);
mViewPager = (ViewPager)toReturn.findViewById(R.id.viewpager);
mViewPager.setAdapter(mPageAdapter);
mViewPager.setOffscreenPageLimit(5);
return toReturn;
}
private class MyPageAdapter extends PagerAdapter
{
#Override
public Object instantiateItem(ViewGroup container, int position)
{
View page = getActivity().getLayoutInflater().inflate(R.layout.view_pager_controls_layout, container, false);
container.addView(page);
return page;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object)
{
container.removeView((View)object);
}
#Override
public int getCount()
{
return 5;
}
#Override
public float getPageWidth(int position)
{
return 1;
}
#Override
public boolean isViewFromObject(View view, Object object)
{
return(view == object);
}
}
}
Thoughts?
Sounds as if it is being destroyed when you move to a different tab. Try setting ViewPager.setOffscreenPageLimit() to a high number and see if it still happens.
Most likely it's because you should be using a childFragmentManager for the nested fragments, instead of the one obtained from the activity.
From a "top level" fragment whenever you gonna do the transaction to include the nested fragment use getChildFragmentManager() instead of getFragmentManager()
I figured it out. The above code was not the problem. The problem had to do with the way I was handling the PagerAdapter inflation. I wasn't doing it exactly how I showed above. The way I was actually using it was preventing an inflation of the views from happening.
Related
I have an Activity with a ViewPager, each page of the ViewPager has a Fragment.
Inside my Screen3Fragment I have a LinearLayout (lly_fragments) where I am showing some other fragments. I start by showing the fragment Screen3_1
public class Screen3Fragment extends Fragment {
private FragmentManager manager;
private FragmentTransaction transaction;
public static Screen3Fragment newInstance() {
final Screen3Fragment mf = new Screen3Fragment();
return mf;
}
public Screen3Fragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_screen3, container, false);
Screen3_1Fragment frag31 = new Screen3_1Fragment();
manager = getChildFragmentManager();
transaction = manager.beginTransaction();
transaction.add(R.id.lly_fragments,frag31,"frag31");
transaction.addToBackStack("frag31");
transaction.commit();
return v;
}
}
This works fine without problems. Problem comes when, from within frag31 (which is inside Screen3Fragment), I want to call fragt32, for that I do the following.
public class Screen3_1Fragment extends Fragment {
private ImageButton imgbt_timer;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_screen3_1,container,false);
imgbt_timer = (ImageButton) v.findViewById(R.id.bT_scr31_timer);
imgbt_timer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
getChildFragmentManager().beginTransaction()
.replace(R.id.lly_fragments, new Screen3_2Fragment(), "frag32")
.commit();
}
});
return v;
}
}
As I read in other answers, the line transaction.replaceshould do the trick and replace the existing frag31 by the given frag32 inside the same given container lly_fragments.
However, I get java.lang.IllegalArgumentException: No view found for id..... I am not sure why.
getFragmentManager() will return always attributes from parent, in most cases the activities. getChildFragmentManager() wil return parent attributes (in your case, Screen3Fragment attributes). It should be used when you add a fragment inside a fragment.
In your case, Screen3Fragment should be added using getFragmentManager() and Screen3_1Fragment should be added using getChildFragmentManager() because Screen3_1Fragment is Screen3Fragment child. Screen3Fragment is the parent.
I recomand you to use always getFragmentManager() with add method, not replace because your parent will be the same.
getChildFragmentManager() can be used when you add a ViewPager inside a fragment.
You can use the callback, as following :
that worked for me, I hope my answers helps you
1) create a interface
public interface ChangeFragmentListener {
void onChangeFragmentLicked(int fragment);
}
2) implement the interface and transaction methods in your activity:
public class MainActivity extends AppCompatActivity implements ChangeFragmentListener {
FragmentTransaction fragmentTransaction;
Fragment1 fragment1;
Fragment2 fragment2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
fragment1 = new Fragment1();
fragment1.setChangeFragmentListener(this);
fragment2 = new Fragment2();
fragment2.setChangeFragmentListener(this);
initListeners();
}
void changeToFrag1() {
fragmentTransaction = getFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.activity_main_fragment_container,fragment1, "");
fragmentTransaction.commit();
}
void changeToFrag2() {
fragmentTransaction = getFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.activity_main_fragment_container, fragment2, "");
fragmentTransaction.commit();
}
#Override
public void onChangeFragmentLicked(int fragment) {
switch (fragment){
case 1:
changeToFrag1();
break;
case 2:
changeToFrag2();
break;
}
}
3) Create object from the interface to handle the callback:
public class Fragment1 extends Fragment {
private ChangeFragmentListener changeFragmentListener;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_fragment1, container, false);
view.findViewById(R.id.fragment1_textView).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
changeFragmentListener.onChangeFragmentLicked(2);
}
});
return view;
}
public Fragment1 setChangeFragmentListener(ChangeFragmentListener changeFragmentListener) {
this.changeFragmentListener = changeFragmentListener;
return this;
}
}
In my application the fragment activity holds two fragments, Fragment A and Fragment B. Fragment B is a view pager that contains 3 fragments.
In my activity, to prevent that the fragment is recreated on config changes:
if(getSupportFragmentManager().findFragmentByTag(MAIN_TAB_FRAGMENT) == null) {
getSupportFragmentManager().beginTransaction().replace(R.id.container, new MainTabFragment(), MAIN_TAB_FRAGMENT).commit();
}
Code for Fragment B:
public class MainTabFragment extends Fragment {
private PagerSlidingTabStrip mSlidingTabLayout;
private LfPagerAdapter adapter;
private ViewPager mViewPager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_tab, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
this.adapter = new LfPagerAdapter(getChildFragmentManager());
this.mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
this.mViewPager.setAdapter(adapter);
this.mSlidingTabLayout = (PagerSlidingTabStrip) view.findViewById(R.id.sliding_tabs);
this.mSlidingTabLayout.setViewPager(this.mViewPager);
}
}
Code for the adapter:
public class LfPagerAdapter extends FragmentPagerAdapter {
private static final int NUM_ITEMS = 3;
private FragmentManager fragmentManager;
public LfPagerAdapter(FragmentManager fm) {
super(fm);
this.fragmentManager = fm;
}
#Override
public int getCount() {
return NUM_ITEMS;
}
#Override
public Fragment getItem(int position) {
Log.d("TEST","TEST");
switch (position) {
case 1:
return FragmentC.newInstance();
case 2:
return FragmentD.newInstance();
default:
return FragmentE.newInstance();
}
}
}
My problem is that I am not able to retain the state of the view pager an its child fragments on orientation changes.
Obviously this is called on every rotation:
this.adapter = new LfPagerAdapter(getChildFragmentManager());
which will cause the whole pager to be recreated, right? As a result
getItem(int position)
will be called on every rotation and the fragment will be created from scratch and losing his state:
return FragmentC.newInstance();
I tried solving this with:
if(this.adapter == null)
this.adapter = new LfPagerAdapter(getChildFragmentManager());
in onViewCreated but the result was that on rotation the fragments inside the pager where removed.
Any ideas how to correctly retain the state inside the pager?
You will need to do 2 things to resolve the issue:
1) You should use onCreate method instead of onViewCreated to instantiate LfPagerAdapter;
i.e.:
public class MainTabFragment extends Fragment {
private PagerSlidingTabStrip mSlidingTabLayout;
private LfPagerAdapter adapter;
private ViewPager mViewPager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
this.adapter = new LfPagerAdapter(getChildFragmentManager());
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_tab, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
this.mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
this.mViewPager.setAdapter(adapter);
this.mSlidingTabLayout = (PagerSlidingTabStrip) view.findViewById(R.id.sliding_tabs);
this.mSlidingTabLayout.setViewPager(this.mViewPager);
}
}
2) You will need to extend FragmentStatePagerAdapter instead of FragmentPagerAdapter
Android will automatically recreate your activity on configuration without this line android:configChanges="keyboardHidden|orientation|screenSize" in you manifest so that you can handle onConfiguration change yourself.
The only way then is to use onSaveInstanceState() in both your activityFragement to save viewPager state(current position for example) and in fragments where you need to save stuff
Example on how you can save current position of viewpager and restore it onConfiguration change
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
int position = mViewPager.getCurrentItem();
outState.Int("Key", position );
}
#Override //then restore in on onCreate();
public void onCreated(Bundle savedInstanceState) {
super.onCreated(savedInstanceState);
// do stuff
if (savedInstanceState != null) {
int position= savedInstanceState.getInt("Key");
mViewPager.setCurrentItem(position)
}
}
Of course, this is a very basic example.
Ps: to restore in fragment use onActivityCreated() instead of onCreate() method.
Here is another example on how to retain state : Click me!
I am using PagerSlidingTab Library for ViewPager. And I want to change Fragment while scrolling of tabs. It is working fine. Check out my code.
I am using AsynTask() on each Fragment.
When the App opens with the MainActivity, First Fragment is attached to the activity, But It shows two AsynTask() dialog message, one from First and another from Second Fragment. And When I scroll to second tab, It shows dialog message of Third Fragment.
So, If I scroll from left to right in tabs, the Fragment right to the current fragment is displayed and if i scroll from right to left, the Fragment left to the current Fragment is displayed.
Please help me to solve the problem.
My Code:
public class PageSlidingTabStripFragment extends Fragment {
public static final String TAG = PageSlidingTabStripFragment.class
.getSimpleName();
public static PageSlidingTabStripFragment newInstance() {
return new PageSlidingTabStripFragment();
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.pager, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
PagerSlidingTabStrip tabs = (PagerSlidingTabStrip) view
.findViewById(R.id.tabs);
ViewPager pager = (ViewPager) view.findViewById(R.id.pager);
MyPagerAdapter adapter = new MyPagerAdapter(getChildFragmentManager());
pager.setAdapter(adapter);
tabs.setViewPager(pager);
}
public class MyPagerAdapter extends FragmentPagerAdapter {
public MyPagerAdapter(android.support.v4.app.FragmentManager fm) {
super(fm);
}
private final String[] TITLES = { "Instant Opportunity", "Events",
"Experts" };
#Override
public CharSequence getPageTitle(int position) {
return TITLES[position];
}
#Override
public int getCount() {
return TITLES.length;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new InstantOpportunity();
case 1:
return new Events();
case 2:
return new Experts();
default:
break;
}
return null;
}
}
}
Explanation:
It turns out there is an easier implementation for scrollable tabs which doesn't involve another library. You can easily implement tabs into your app using normal Android code straight from the default SDK.
The Code
Main Class:
public class PageSlidingTabStripFragment extends Fragment {
//Variables
private ViewPager viewPager;
private PagerTitleStrip pagerTitleStrip;
public PageSlidingTabStripFragment() {
// Required empty public constructor
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//Find your pager declared in XML
viewPager = (ViewPager) getView().findViewById(R.id.pager);
//Set the viewPager to a new adapter (see below)
viewPager.setAdapter(new MyAdapter(getFragmentManager()));
//If your doing scrollable tabs as opposed to fix tabs,
//you need to find a pagerTitleStrip that is declared in XML
//just like the pager
pagerTitleStrip = (PagerTitleStrip)
getView().findViewById(R.id.pager_title_strip);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.[your layout name here], container, false);
}
}
Adapter:
//Note: this can go below all of the previous code. Just make sure it's
//below the last curly bracket in your file!
class MyAdapter extends FragmentStatePagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int arg0) {
Fragment fragment = null;
if (arg0 == 0) {
fragment = new InstantOpportunity();
}
if (arg0 == 1) {
fragment = new Events();
}
if (arg0 == 2) {
fragment = new Experts();
}
return fragment;
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
if (position == 0) {
return "Instant Opportunity";
}
if (position == 1) {
return "Events";
}
if (position == 2) {
return "Experts";
}
return null;
}
}
Conclusion:
I hope this helps you understand another way to make scrollable tabs! I have examples on my Github Page about how to make each type (That being Fixed or Scrollable).
Links:
Fixed Tabs Example - Click Here
Scrollable Tabs Example - Click Here
Hope this helps!
Edit:
When asked what to import, make sure you select the V4 support fragments.
please use this example..its very easy.i already implement that.
reference link
hope its useful to you.its best example of pager-sliding-tabstrip.
Use
framelayout compulsory:
FrameLayout fl = new FrameLayout(getActivity());
fl.addView(urFragementView);
and then set your fragement view in this framelayout.
I put a FragmentTabHost into a ViewPager, but the tab content has gone after I rotate the device. The tab content will come back if I click on another tab to refresh content. Is there anything wrong in my code? Please help me know.
public class MyActivity extends FragmentActivity
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
LayoutInflater inflater = getLayoutInflater();
View tabView = inflater.inflate(R.layout.tab, null);
FragmentTabHost tabHost = (FragmentTabHost) tabView.findViewById(android.R.id.tabhost);
tabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
tabHost.addTab(tabHost.newTabSpec("tab1").setIndicator("Tab1"), TabContent1Fragment.class, null);
tabHost.addTab(tabHost.newTabSpec("tab2").setIndicator("Tab2"), TabContent2Fragment.class, null);
View page2 = inflater.inflate(R.layout.page2, null);
ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
List<View> list = new ArrayList<View>();
list.add(page2);
list.add(tabView);
viewPager.setAdapter(new DemoPagerAdapter(list));
}
}
public class TabContent1Fragment extends Fragment
{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
return inflater.inflate(R.layout.tab_content_1, null);
}
}
public class DemoPagerAdapter extends PagerAdapter
{
private List<View> mModeViewPageList;
public DemoPagerAdapter(List<View> modeViewPageList)
{
this.mModeViewPageList = modeViewPageList;
}
#Override
public Object instantiateItem(ViewGroup container, int position)
{
container.addView(mModeViewPageList.get(position), 0);
return mModeViewPageList.get(position);
}
#Override
public void destroyItem(ViewGroup container, int position, Object object)
{
container.removeView(mModeViewPageList.get(position));
}
#Override
public int getCount()
{
return mModeViewPageList.size();
}
#Override
public boolean isViewFromObject(View view, Object o)
{
return view == o;
}
}
Thanks to my friend, finally I found the reason was that I used PagerAdapter.
When device is rotated, all views will be recreated. But without extra codes for fragment management, PagerAdapter is not able to mange the state of the fragments inside views (tab content fragments in realtabcontent in my case) and the child fragment of a view will disappear after rotation.
So I should change all views for ViewPager into fragments and use FragmentPagerAdapter instead.
One more thing, it should be used getChildFragmentManager() from Fragment in onCreateView instead of getSupportFragmentManger() from FragmentActivity to manage the child fragments in a fragment.
I wanted to point out an important point in Light's answer. If you convert an Activity to a Fragment then you may have been using getSupportFragmentManager. When converting it, you may have changed it to getActivity().getSupportFragmentManager(). It will seemingly work until you leave and return to the fragment, and you'll find some fragments missing until you scroll the pager.
The solution is to change getActivity().getSupportFragmentManager() to getChildFragmentManager().
I have an Activity with a ViewPager containing multiple fragments. how can i now access a TextView in one of that fragments to change its text from the main activity? I tried multiple ways and they all ended in a NullPointerException.
Activity:
public class SummonerOverview extends SherlockFragmentActivity implements TabListener, OnPageChangeListener {
private ViewPager mPager;
private PagerAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.summoner_overview);
initialize();
}
private void initialize() {
// initialize Pager
mPager = (ViewPager) findViewById(R.id.viewpager);
mAdapter = new PagerAdapter(getSupportFragmentManager());
mPager.setAdapter(mAdapter);
mPager.setCurrentItem(1);
mPager.setOnPageChangeListener(this);
}
}
PagerAdapter:
public class PagerAdapter extends FragmentPagerAdapter {
public PagerAdapter(FragmentManager fm) {
super(fm);
frags = new Fragment[3];
frags[0] = new StatisticsFragment(0);
frags[1] = new RatingsFragment(1);
frags[2] = new HistoryFragment(2);
}
private final int NUM_PAGES = 3;
Fragment[] frags;
#Override
public Fragment getItem(int arg0) {
if (arg0 == 0)
return frags[0];
else if (arg0 == 1)
return frags[1];
else
return frags[2];
}
#Override
public int getCount() {
return NUM_PAGES;
}
}
The Fragment:
public class StatisticsFragment extends SherlockFragment {
public StatisticsFragment(int fragNr) {
this.fragNr = fragNr;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_overview_statistics, container, false);
return v;
}
}
The Textview in the StatisticsFragment is labeled with an id in the fragment_overview_statistics.xml, but when i try
TextView tv = (TextView) findViewById(R.id.id_of_the_textview)
tv.setText("text");
from within the onCreate() Method of the Activity after the initialize() Method, i get an Exception.
Okay, after another hour of googling, i think i solves my own question (although i'm sure there is a better method to solve that)
I now hold all the Data that is displayed by the fragments in the MainActivity and make the Fragmets consume this Data in their onCreateView() Method by using public Methods of the Activity.
In the PagerAdapter, i overwrote getItemPosition() to:
public int getItemPosition(Object object) {
return POSITION_NONE;
}
Now, everytime i update some of the Data, i also call mAdapter.notifyDataSetChanged() which leads into a recreation of all fragments.
It works, although it looks like a poor hack for me. Im sure there must be a better solution because now i have to recreate all fragments for changing one TextView of one Fragment, what is surely not the way it is intended to be done.