fragments: onCreateView is not called after fragment was added - android

I have simple app with fragments.
At the beginning list of fragments is empty.
And there are 2 buttons:
ADD FRAGMENT
REMOVE FRAGMENT
And following use-case:
Add fragment
Add fragment
Remove first fragment
Add fragment
As result onCreateView() on 4th step is not executed.
If I add fragment again on 5th step - onCreateView is executed again.
Why is it so? I didn't find right answer in google.
Source code:
public class MyActivity extends FragmentActivity {
private ViewPager pager;
private FragmentAdapter adapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
pager = (ViewPager) findViewById(R.id.pager);
final Button addButton = (Button) findViewById(R.id.add_button);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
adapter.addFragment(new MyFragment());
adapter.notifyDataSetChanged();
}
});
final Button removeButton = (Button) findViewById(R.id.remove_button);
removeButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
adapter.removeFragment(0);
adapter.notifyDataSetChanged();
}
});
adapter = new FragmentAdapter(getSupportFragmentManager());
pager.setAdapter(adapter);
pager.setOffscreenPageLimit(10);
}
private class FragmentAdapter extends FragmentStatePagerAdapter {
final List<MyFragment> fragments = new ArrayList<MyFragment>();
public FragmentAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
return fragments.get(i);
}
#Override
public int getCount() {
return fragments.size();
}
public void addFragment(MyFragment fragment) {
fragments.add(fragment);
}
public void removeFragment(int index) {
fragments.remove(index);
}
}
private class MyFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment, container, false);
}
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add"
android:id="#+id/add_button"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Remove first"
android:id="#+id/remove_button"/>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Text"
android:id="#+id/textView"
android:layout_gravity="center_horizontal"/>
</LinearLayout>

OnCreateView() is only called when the actual Fragment is being drawn on the screen. Since you have removed a fragment at the beginning the pager no longer looks at the same fragment.
To better understand what is going on put a visible number on each of the fragments and then try adding and removing the fragments.

The issue is 'FragmentStatePagerAdapter' and the way it's implemented. The way to fix it is this:
Go to googlesource and grab the source for 'FragmentStatePagerAdapter'.
refactor (name, package,etc) to make it your own implementation.
Extend from your NEW version of 'FragmentStatePagerAdapter'
Modify your NEW version of 'FragmentStatePagerAdapter' using these steps below:
a) Change the mFragments.set(index, object) command to mFragments.add(index, object), in the the 'instantiateItem()' function.
b) Change the mFragments.set(index, object) command to mFragments.remove(index), in the 'destroyItem' function.
All of this assumes that you are using an ArrayList to hold fragments in your 'extends' class and that they are synced to match the ViewPager.
You will need to add a 'pageIndex' to each fragment, so that you can tell ViewPager when your item has 'moved' (due to deleting an item, that is NOT the LAST item).
This took several days to run down...hope it helps someone :-)

Related

How to run multiple activities and also close those activities

I have an activity in which the user enters the no of items to be created.
I have created an activity to enter the details of the item.
After pressing a button then the activity for entering details starts
For more than one item the activity should run one after the other and if the user presses back button a popup arises to confirm cancel the process.
I wrote in Kotlin language
I tried by using for loop but all the activities run in the background, I should press back button for all the activity
You can use a ViewPager in your activity and a adapt a list of fragments for each item using FragmentPagerAdapter.
The backstack will contain only the fragment holding the ViewPager so presing back will close the activity alltogheter.
Main Activity:
public class MyActivity extends AppCompatActivity {
private ViewPager myViewPager;
private MyFragmentAdapter adapter;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
adapter = new MyFragmentAdapter(getSupportFragmentManager());
adapter.setFragments("5");
myViewPager = findViewById(R.id.myViewPager);
myViewPager.setAdapter(adapter);
}
}
Fragment Adapter :
class MyFragmentAdapter extends FragmentPagerAdapter {
private List<Fragment> fragments = new ArrayList<>();
public MyFragmentAdapter(#NonNull FragmentManager fm) {
super(fm);
}
#NonNull
#Override
public Fragment getItem(int position) {
return fragments.get(position);
}
#Override
public int getCount() {
return fragments.size();
}
public void setFragments(String noOfFragments){
int intFragments = Integer.parseInt(noOfFragments);
for (int i = 0; i < intFragments; i++){
this.fragments.add(new Fragment());
}
}
}
Activity layout:
<?xml version="1.0" encoding="utf-8"?>
<ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"enter code here>
<ViewPager
android:id="#+id/myViewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</ConstraintLayout>
I have removed the views qualifiers, you should fill in with either support library or androidx

Android fragment transaction with SlidingTabLayout not working in API level < 21

in my app I have an ActionBarActivity (I'm using support library with AppCompat) that uses the SlidingTabLayout class from Google (taken from here). So this is the XML code of the activity's layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_series_details"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".SeriesDetailsActivity">
<com.my.package.SlidingTabLayout
android:id="#+id/series_details_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="#color/primary_material_dark" />
<android.support.v4.view.ViewPager
android:id="#+id/series_details_pager"
android:layout_height="0dp"
android:layout_width="match_parent"
android:layout_weight="1" />
</LinearLayout>
In this activty, when user press an option in the action bar, I want to add a Fragment with a custom animation. This is the code that handle menu click:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
/* ... OTHER CASES ... */
case R.id.menu_voption:
newFragment = MyNewFragment.newInstance();
getSupportFragmentManager().beginTransaction()
.setCustomAnimations(
R.anim.slide_up,
R.anim.slide_down
)
.add(R.id.activity_series_details, newFragment)
.commit();
editing = true;
break;
default:
return super.onOptionsItemSelected(item);
}
return true;
Doing this, my new fragment is correctly added to the activty and replace the currente fragment but not tab layout, tha remains visible. So I've tryed to add this line before start transaction:
tabsHost.setVisibility(View.GONE);
where tabsHost is the SlidingTabLayout. With this modification, the tabs layout disappear and the new fragment is correctly shown, but only in the API Level >= 21. In my Samsung Galaxy S4 (that runs API 19) and in all other emulators with lesser API level than 21 (my target is 11+), the tabs layout disappear but new fragment is not visible. I'm pretty sure is my fault, but I can't figure why. Thanks all for attention.
Since the SlidingTabLayout is not a fragment, it cannot be managed by the FragmentManager. You would have to make it part of a fragment and add it to your Activity. This is possible with getChildFragmentManager.
Move your activity layout to a fragment:
activity_main.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_series_details"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
fragment_sliding_tab.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_series_details"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.my.package.SlidingTabLayout
android:id="#+id/series_details_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="#color/primary_material_dark" />
<android.support.v4.view.ViewPager
android:id="#+id/series_details_pager"
android:layout_height="0dp"
android:layout_width="match_parent"
android:layout_weight="1" />
</LinearLayout>
SlidingTabFragment.java
public class SlidingTabFragment extends Fragment {
private PagerAdapter mPagerAdapter;
private ViewPager mViewPager;
public static SlidingTabFragment newInstance() {
SlidingTabFragment fragment = new SlidingTabFragment();
return fragment;
}
public SlidingTabFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mPagerAdapter = new PagerAdapter(getChildFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) view.findViewById(R.id.series_details_pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
SlidingTabLayout tabs = (SlidingTabLayout) view.findViewById(R.id.series_details_tabs);
tabs.setViewPager(mViewPager);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_sliding_tab, container, false);
}
}
Add your fragment in your Activity's onCreate:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Fragment slidingTabFragment = SlidingTabFragment.newInstance();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.activity_series_details, slidingTabFragment).commit();
}

Android ViewPager findViewById(R.id.viewPager) always returns null

I'm trying to put together a simple view pager app that I want to extend latter on.
Currently when I'm calling ViewPager vPager = (ViewPager) findViewById(R.id.viewPager); in the onCreate method of my FragmentActivity it returns null.
Here is the full explanation:
My GUI xml looks like this:
\res\layout\view_fragment.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Medium Text"
android:textAppearance="?android:attr/textAppearanceMedium" />
</LinearLayout>
The corresponding Fragment class looks like this:
public class ViewFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.view_fragment, container, false);
}
}
and I have a pager xml like this:
\res\layout\view_pager.xml
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
And I have the Pager Activity which looks like this:
public class ScreenPagerActivity extends FragmentActivity {
private ViewPager vPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view_fragment); // The view
vPager = (ViewPager) findViewById(R.id.viewPager);
ScreenPagerAdapter pagerAdapter = new ScreenPagerAdapter(getSupportFragmentManager());
vPager.setAdapter(pagerAdapter);
}
#Override
public void onBackPressed() {
if (vPager.getCurrentItem() == 0) {
// If the user is currently looking at the first step, allow the system to handle the
// Back button. This calls finish() on this activity and pops the back stack.
super.onBackPressed();
} else {
// Otherwise, select the previous step.
vPager.setCurrentItem(vPager.getCurrentItem() - 1);
}
}
private class ScreenPagerAdapter extends FragmentStatePagerAdapter {
public ScreenPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public android.support.v4.app.Fragment getItem(int position) {
return new ViewFragment();
}
#Override
public int getCount() {
return 5;
}
}
}
However, the statement vPager = (ViewPager) findViewById(R.id.viewPager); always returns null. Can anyone tell me where I am going wrong.
Just incase it helps, my Manifest file for the activity snippet looks like this:
<activity
android:name="uk.co.jeeni.android.androidpagerview.ScreenPagerActivity"
android:label="#string/app_name"
android:parentActivityName="uk.co.jeeni.android.androidpagerview.MainActivity"
android:uiOptions="splitActionBarWhenNarrow" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="uk.co.jeeni.android.androidpagerview.MainActivity" />
</activity>
Please help!!!
Thanks
I think you choose the wrong view. Try this:
setContentView(R.layout.view_pager); // The view where your ViewPager is!
instead of
setContentView(R.layout.view_fragment); // The view for your Fragment.
That's why your ViewPager returns null, because the method can't find it on the choosen layout.
HTH

Navigate among fragments within one activity

I would like to use one Activity which holds several fragments and navigate among the fragments. For example, in the activity, there is a list view which is a fragment, when user select one item from the list, the view will navigate to another fragment, How could this be implemented?
I know there is a nice tutorial on the developer site, but it handles the tablet screen in which two pane layout with one list fragment and one detailed fragment showing in one screen. I only want to navigate among fragments without show two fragments in one screen.
Are there tutorials can teach me how to do it?
In the nutshell the answer to your question is to notify your host activity and then have your host activity replace your current fragment container using FragmentManager.
One of the approach is to make an interface in your first fragment, have your host activity register/listen (implement) to this interface and then have your FragmentManager to replace the container content with the second fragment on listener callback.
I'm not sure about tutorial but here is my snippet:
First Fragment
public class First extends Fragment{
private static onMySignalListener listener;
//call this function from whatever you like i.e button onClickListener
public void switchWindow() {
if(listener != null){
listener.onMySignal();
}
}
public interface onMySignalListener {
//customize this to your liking
//plain without argument
void onMySignal();
//with argument
void onMySignalWithNum(int mNum);
}
public static void setOnMySignalListener(onMySignalListener listener) {
First.listener = listener;
}}
Host Activity
public class HostActivity extends FragmentActivity implements onMySignalListener{
private final String ADD_TAG_IF_NECESSARY = "mTag";
#Override
public void onCreate(Bundle ssi) {
setContentLayout(R.layout.main);
FirstFragment.setOnMySignalListener(this);
}
#Override
public void onMySignal() {
//if you're using compat library
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
//initialize your second fragment
sfragment = SecondFragment.newInstance(null);
//replace your current container being most of the time as FrameLayout
transaction.replace(R.id.container, fragment, ADD_TAG_IF_NECESSARY);
transaction.commit();
}
#Override
public void onMySignalWithNum(int mNum) {
//you can do the same like the above probably with your own customization
}}
This is only an example on how you'd implement interface, kindly tidy it up by yourself. And please be noted though that this is not effective if you have a lot of fragment wanting to notify your host activity about something. doing so will lead you to implement various listener to your host activity.
I think this will be useful for you. It is example of two fragments in one screen works independently.
MainActivity :
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
Fragment newFragment = new Test();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.add(R.id.UprLayout, newFragment);
// transaction.addToBackStack(null);
transaction.commit();
Fragment newFragment2 = new TestRight();
FragmentTransaction transaction2 = getFragmentManager().beginTransaction();
transaction2.add(R.id.dwnLayout, newFragment2);
// transaction.addToBackStack(null);
transaction2.commit();
}
}
main_activity.xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/LinearLayout2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center|center_horizontal"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/UprLayout"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:orientation="vertical" />
<LinearLayout
android:id="#+id/dwnLayout"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:orientation="vertical" />
</LinearLayout>
Fragment Test :
public class Test extends Fragment {
TextView tv;
#Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.test, container, false);
return view;
}
}
Fragment TestRight :
public class TestRight extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.test_right, container, false);
return view;
}
#Override
public void onStart() {
super.onStart();
Button button = (Button)getActivity().findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Fragment newFragment = new Right2nd();
FragmentTransaction transaction = getFragmentManager()
.beginTransaction();
transaction.replace(R.id.dwnLayout, newFragment);
transaction.addToBackStack("aa");
transaction.commit();
//transaction.add(R.id.frag, newFragment).commit();
}
});
}
}
test.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:gravity="center"
android:orientation="vertical" >
<TextView
android:id="#+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:text="test"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="50sp" />
</LinearLayout>
test_right.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:gravity="center"
android:orientation="vertical" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Test right"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="45sp" />
</LinearLayout>
Fragment Right2nd :
public class Right2nd extends Fragment{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View vw = inflater.inflate(R.layout.right_2nd, container, false);
return vw;
}
}
right_2nd.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:gravity="center"
android:orientation="vertical" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Right 2nd"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="50sp" />
</LinearLayout>
I know this is quite old question but this is currently implemented in Navigation Component https://developer.android.com/guide/navigation/
Here is a very nice tutorial about it. MULTIPLE FRAGMENTS STACK IN EACH VIEWPAGER TAB
I think ChildFragment
would do the job for you. Ignore the Tab ViewPager. It's performing the same thing in multiple tabs. Hope this helps a bit.

Fragment Inside Fragment

I need help regarding working on fragment inside fragment, actually I
am facing a problem on pressing back button. Application Main screen
has buttons and pressing on each button view replace with new
fragment(and that fragment contain inside another fragment),
dynamically adding/replacing fragment is working fine, by pressing
button1 fragment replaced, same happens when pressing button, but if
I press the button again, got an exception:
"Duplicate id 0x7f05000a, tag null, or parent id 0x7f050009 with
another fragment for com........ fragmentname"
means fragment or inner fragments are already added and I am trying
to add them again, anybody has idea how to work with fragment inside
fragment and moving back and forth without any problem, thanks for the
support.
MainActivity, where fragments are dynamical added and
replaced.
public class FragmentInsideFragmentTestActivity extends Activity {
private Button button1;
private Button button2;
private Button button3;
private Button button4;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button1 =(Button) this.findViewById(R.id.button1);
button1.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
onButtonClick(view);
}
});
button2 =(Button) this.findViewById(R.id.button2);
button2.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
onButtonClick(view);
}
});
button3 =(Button) this.findViewById(R.id.button3);
button3.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
onButtonClick(view);
}
});
button4 =(Button) this.findViewById(R.id.button4);
button4.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
onButtonClick(view);
}
});
}
public void onButtonClick(View v) {
Fragment fg;
switch (v.getId()) {
case R.id.button1:
fg=FirstFragment.newInstance();
replaceFragment(fg);
break;
case R.id.button2:
fg=SecondFragment.newInstance();
replaceFragment(fg);
break;
case R.id.button3:
fg=FirstFragment.newInstance();
replaceFragment(fg);
break;
case R.id.button4:
fg=SecondFragment.newInstance();
replaceFragment(fg);
break;
}
}
private void replaceFragment(Fragment newFragment) {
FragmentTransaction trasection = getFragmentManager().beginTransaction();
if(!newFragment.isAdded()) {
try {
//FragmentTransaction trasection =
getFragmentManager().beginTransaction();
trasection.replace(R.id.linearLayout2, newFragment);
trasection.addToBackStack(null);
trasection.commit();
} catch (Exception e) {
// TODO: handle exception
// AppConstants.printLog(e.getMessage());
} else {
trasection.show(newFragment);
}
}
}
Here is Layout: main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button1" />
<Button
android:id="#+id/button2"
android:text="Button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="#+id/button3"
android:text="Button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="#+id/button4"
android:text="Button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" />
</LinearLayout>
Hope I tried to clear my problem.
AFAIK, fragments cannot hold other fragments.
UPDATE
With current versions of the Android Support package -- or native fragments on API Level 17 and higher -- you can nest fragments, by means of getChildFragmentManager(). Note that this means that you need to use the Android Support package version of fragments on API Levels 11-16, because even though there is a native version of fragments on those devices, that version does not have getChildFragmentManager().
I needed some more context, so I made an example to show how this is done. The most helpful thing I read while preparing was this:
Creating and Using Fragments
Activity
activity_main.xml
Add a FrameLayout to your activity to hold the parent fragment.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Activity"/>
<FrameLayout
android:id="#+id/parent_fragment_container"
android:layout_width="match_parent"
android:layout_height="200dp"/>
</LinearLayout>
MainActivity.java
Load the parent fragment and implement the fragment listeners. (See fragment communication.)
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity implements ParentFragment.OnFragmentInteractionListener, ChildFragment.OnFragmentInteractionListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Begin the transaction
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.parent_fragment_container, new ParentFragment());
ft.commit();
}
#Override
public void messageFromParentFragment(Uri uri) {
Log.i("TAG", "received communication from parent fragment");
}
#Override
public void messageFromChildFragment(Uri uri) {
Log.i("TAG", "received communication from child fragment");
}
}
Parent Fragment
fragment_parent.xml
Add another FrameLayout container for the child fragment.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="20dp"
android:background="#91d0c2">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Parent fragment"/>
<FrameLayout
android:id="#+id/child_fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
</LinearLayout>
ParentFragment.java
Use getChildFragmentManager in onViewCreated to set up the child fragment.
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
public class ParentFragment extends Fragment {
private OnFragmentInteractionListener mListener;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_parent, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
Fragment childFragment = new ChildFragment();
FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
transaction.replace(R.id.child_fragment_container, childFragment).commit();
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void messageFromParentFragment(Uri uri);
}
}
Child Fragment
fragment_child.xml
There is nothing special here.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="20dp"
android:background="#f1ff91">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Child fragment"/>
</LinearLayout>
ChildFragment.java
There is nothing too special here, either.
import android.support.v4.app.Fragment;
public class ChildFragment extends Fragment {
private OnFragmentInteractionListener mListener;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_child, container, false);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void messageFromChildFragment(Uri uri);
}
}
Notes
The support library is being used so that nested fragments can be used before Android 4.2.
Since Android 4.2 (API 17) nested fragments become available http://developer.android.com/about/versions/android-4.2.html#NestedFragments
To place fragment inside other fragment use getChildFragmentManager()
It also available in support library!
you can use getChildFragmentManager() function.
example:
Parent fragment :
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.parent_fragment, container,
false);
}
//child fragment
FragmentManager childFragMan = getChildFragmentManager();
FragmentTransaction childFragTrans = childFragMan.beginTransaction();
ChildFragment fragB = new ChildFragment ();
childFragTrans.add(R.id.FRAGMENT_PLACEHOLDER, fragB);
childFragTrans.addToBackStack("B");
childFragTrans.commit();
return rootView;
}
Parent layout (parent_fragment.xml):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white">
<FrameLayout
android:id="#+id/FRAGMENT_PLACEHOLDER"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
Child Fragment:
public class ChildFragment extends Fragment implements View.OnClickListener{
View v ;
#Override
public View onCreateView(LayoutInflater inflater,
#Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
// TODO Auto-generated method stub
View rootView = inflater.inflate(R.layout.child_fragment, container, false);
v = rootView;
return rootView;
}
#Override
public void onClick(View view) {
}
}
Fragments can be added inside other fragments but then you will need to remove it from parent Fragment each time when onDestroyView() method of parent fragment is called. And again add it in Parent Fragment's onCreateView() method.
Just do like this :
#Override
public void onDestroyView()
{
FragmentManager mFragmentMgr= getFragmentManager();
FragmentTransaction mTransaction = mFragmentMgr.beginTransaction();
Fragment childFragment =mFragmentMgr.findFragmentByTag("qa_fragment")
mTransaction.remove(childFragment);
mTransaction.commit();
super.onDestroyView();
}
I solved this problem. You can use Support library and ViewPager. If you don't need swiping by gesture you can disable swiping. So here is some code to improve my solution:
public class TestFragment extends Fragment{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.frag, container, false);
final ArrayList<Fragment> list = new ArrayList<Fragment>();
list.add(new TrFrag());
list.add(new TrFrag());
list.add(new TrFrag());
ViewPager pager = (ViewPager) v.findViewById(R.id.pager);
pager.setAdapter(new FragmentPagerAdapter(getChildFragmentManager()) {
#Override
public Fragment getItem(int i) {
return list.get(i);
}
#Override
public int getCount() {
return list.size();
}
});
return v;
}
}
P.S.It is ugly code for test, but it improves that it is possible.
P.P.S Inside fragment ChildFragmentManager should be passed to ViewPagerAdapter
It's nothing complicated. We cannot use getFragmentManager() here. For using Fragments inside a Fragment, we use getChildFragmentManager(). Rest will be the same.
Use getChildFragmentManager(), follow the link :
Nested Fragment
You can add FrameLayout to the fragment and replace it with another fragment when it initializes.
This way , you could consider the other fragment to be inside the first fragment.
Curently in nested fragment, the nested one(s) are only supported if they are generated programmatically! So at this time no nested fragment layout are supported in xml layout scheme!
That may help those who works on Kotlin you can use extension function
so create a kotlin file let's say "util.kt" and add this piece of code
fun Fragment.addChildFragment(fragment: Fragment, frameId: Int) {
val transaction = childFragmentManager.beginTransaction()
transaction.replace(frameId, fragment).commit()
}
Let's say this is the class of the child
class InputFieldPresentation: Fragment()
{
var views: View? = null
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?,
savedInstanceState: Bundle?): View? {
views = inflater!!.inflate(R.layout.input_field_frag, container, false)
return views
}
override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
...
}
...
}
Now you can add the children to the father fragment like this
FatherPresentation:Fragment()
{
...
override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val fieldFragment= InputFieldPresentation()
addChildFragment(fieldFragment,R.id.fragmet_field)
}
...
}
where R.id.fragmet_field is the id of the layout which will contain the fragment.This lyout is inside the father fragment of course.
Here is an example
father_fragment.xml:
<LinearLayout android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android"
>
...
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:id="#+id/fragmet_field"
android:orientation="vertical"
>
</LinearLayout>
...
</LinearLayout>
There is no support for MapFragment, Android team says is working on it since Android 3.0. Here more information about the issue But what you can do is by creating a Fragment that returns a MapActivity. Here is a code example. Thanks to inazaruk:
How it works:
MainFragmentActivity is the activity that extends FragmentActivity and hosts two MapFragments.
MyMapActivity extends MapActivity and has MapView.
LocalActivityManagerFragment hosts LocalActivityManager.
MyMapFragment extends LocalActivityManagerFragment and with help of TabHost creates internal instance of MyMapActivity.
If you have any doubt please let me know
Hi I solved this problem by putting per Fragment into distinct layout.And I made just related Layout visible and made the others visibilities gone.
I mean:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout android:id="#+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button android:layout_width="wrap_content"
android:id="#+id/button1"
android:layout_height="wrap_content"
android:text="Button1"></Button>
<Button android:text="Button2"
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:text="Button3"
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:text="Button4"
android:id="#+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
</LinearLayout>
<LinearLayout android:layout_width="full_screen"
android:layout_height="0dp"
android:layout_weight="1"
android:id="action_For_Button1"
android:visibility="visible">
<Fragment android:layout_width="full_screen"
android:layout_height="full_screen"
android:id="fragment1"
.
.
.
/ >
</LinearLayout>
<LinearLayout android:layout_width="full_screen"
android:layout_height="0dp"
android:id="action_For_Button1"
android:layout_weight="1"
android:visibility="gone">
<Fragment android:layout_width="full_screen"
android:layout_height="full_screen"
android:id="fragment2"
.
.
.
/ >
</LinearLayout>
.
.
.
</LinearLayout>
I assumed that you will open your page as button 1 is clicked.You can control your fragment's visibilities on click action.You can make related Layout visible and the others gone and by Fragment Manager you can take your fragment.This approach worked for me.And since view that has visibility:gone is invisible, and it doesn't take any space for layout purposes I think this approach does not cause any space problem.
P.S:I just tried to explain my solution code may have syntax mistakes or uncompleted structure.

Categories

Resources