Unable to update fragment text while exchanging cards

Question

I am working on a map and flip map scroll function, and I am using ViewPager and snippets.

My problem: I can’t update the TextView fragments inside when I scroll the map from left to right or left, but when I flip the map, it updates the user interface. I tried everything that is available over the Internet, but none of the soltuion works for me.

I follow this link https://github.com/jamesmccann/android-view-pager-cards

Here is my code

public class CardContainerFragment extends Fragment { private boolean cardFlipped = false; static TextView textview; public CardContainerFragment() { setHasOptionsMenu(true); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_card_container, container, false); LinearLayout ll = (LinearLayout)rootView.findViewById(R.id.layout); rootView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { flipCard(); } }); getChildFragmentManager() .beginTransaction() .add(R.id.container, new CardFrontFragment()) .commit(); Message msg = handler.obtainMessage(); msg.arg1 = 1; handler.sendMessage(msg); return rootView; } final Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { int page = CardActivity.mViewPager.getCurrentItem(); int page_index = page+1; String current_page = page_index + " of " + card_activity.deck_map.size(); CardActivity.tv.setText(current_page); super.handleMessage(msg); } }; public void flipCard() { Fragment newFragment = null; Message msg = handler.obtainMessage(); msg.arg1 = 1; handler.sendMessage(msg); if (cardFlipped) { newFragment = new CardFrontFragment(); } else { newFragment = new CardBackFragment(); } getChildFragmentManager() .beginTransaction() .setCustomAnimations( R.animator.card_flip_right_in, R.animator.card_flip_right_out, R.animator.card_flip_left_in, R.animator.card_flip_left_out) .replace(R.id.container, newFragment) .commit(); cardFlipped = !cardFlipped; } public static class CardFrontFragment extends Fragment { public CardFrontFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_card, container, false); textview = (TextView)rootView.findViewById(R.id.card_front); String card_front_string = card_activity.arraylst.get(CardActivity.mViewPager.getCurrentItem()); Log.e("current Item",CardActivity.mViewPager.getCurrentItem()+""); String complete_text = card_front_string +" \n \n + \n Tap now to flip this card."; textview.setText(complete_text); return rootView; } } public static class CardBackFragment extends Fragment { public CardBackFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_card_back, container, false); TextView textview = (TextView)rootView.findViewById(R.id.card_back); textview.setMovementMethod(new ScrollingMovementMethod()); String card_front_string = card_activity.arraylst.get(CardActivity.mViewPager.getCurrentItem()); String deck_data = card_activity.deck_map.get(card_front_string); textview.setText(deck_data); return rootView; } } 

Here is my adapter code

 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); try { setContentView(R.layout.card_example); tv = (TextView)findViewById(R.id.tv_card_number); tv1 = (TextView)findViewById(R.id.tv_card_index); FragmentManager m = getFragmentManager(); CardPagerAdapter adapter = new CardPagerAdapter(m); index = getIntent().getStringExtra("index"); card_activity.cardCounter = Integer.parseInt(index); int count = card_activity.cardCounter; int final_count = count+1; String current_page = final_count+" of "+card_activity.deck_map.size(); //CardActivity.tv.setText(current_page); mViewPager = (ViewPager) findViewById(R.id.view_pager); // mViewPager.setAllowedSwipeDirection(CustomViewPager.SwipeDirection.all); mViewPager.setAdapter(adapter); mViewPager.setCurrentItem(card_activity.cardCounter); //mViewPager.setOffscreenPageLimit(1); //mViewPager.setOnPageChangeListener(new pagechangelistener()) //Log.e("current Item",CardActivity.mViewPager.getCurrentItem()+""); }catch(Exception e){ e.printStackTrace(); } } public class CardPagerAdapter extends android.support.v13.app.FragmentStatePagerAdapter { public CardPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int i) { mViewPager.setOffscreenPageLimit(0); int page = mViewPager.getCurrentItem(); int page_index = page+1; String current_page = " of " + card_activity.deck_map.size(); tv.setText(current_page); tv1.setText(String.valueOf(page_index)); CardContainerFragment cardContainerFragment = new CardContainerFragment(); cardContainerFragment.current_index_front = page; cardContainerFragment.current_index_back = page; String card_front_string = card_activity.arraylst.get(page); CardContainerFragment.complete_text_front = card_front_string +" \n \n + \n Tap now to flip this card."; Bundle b = new Bundle(); b.putInt("index",page); CardContainerFragment.complete_text_back = card_activity.deck_map.get(card_front_string); cardContainerFragment.setArguments(b); return cardContainerFragment; } @Override public int getCount() { int len = card_activity.deck_map.size(); return len; } @Override public int getItemPosition(Object object) { return POSITION_NONE; } } 

Please let me know what I'm doing wrong here.

Thank you in advance

Answer 1

Finally, I can do this with some effort.

After searching, I find out that getItems (the method in CardPagerAdapter ) is called twice because Android creates extra fragments for a smooth transition, and I sent or received the wrong position of the fragments from getItems .

By letting the android create one additional fragment and sending the correct position, I can solve this problem.

Here is my updated code

 public class CardActivity extends android.support.v4.app.FragmentActivity { public TextView tv; public static String index=null; public static ViewPager mViewPager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); try { setContentView(R.layout.card_example); tv = (TextView)findViewById(R.id.tv_card_number); FragmentManager m = getFragmentManager(); CardPagerAdapter adapter = new CardPagerAdapter(m); index = getIntent().getStringExtra("index"); card_activity.cardCounter = Integer.parseInt(index); int count = card_activity.cardCounter; int final_count = count+1; String current_page = final_count+" of "+card_activity.deck_map.size(); mViewPager = (ViewPager) findViewById(R.id.view_pager); mViewPager.setOffscreenPageLimit(0); mViewPager.setAdapter(adapter); mViewPager.setCurrentItem(card_activity.cardCounter); String current_page_temp =final_count+" of " + card_activity.deck_map.size(); tv.setText(current_page_temp); mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { Log.e("aaa",position+""); String current_page = position+1 + " of " + card_activity.deck_map.size(); tv.setText(current_page); } @Override public void onPageScrollStateChanged(int state) { } }); }catch(Exception e){ e.printStackTrace(); } } public class CardPagerAdapter extends android.support.v13.app.FragmentStatePagerAdapter { public CardPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int i) { CardContainerFragment cardContainerFragment = new CardContainerFragment(); Bundle b = new Bundle(); b.putInt("index",i); cardContainerFragment.setArguments(b); return cardContainerFragment; } @Override public int getCount() { int len = card_activity.deck_map.size(); return len; } @Override public int getItemPosition(Object object) { return POSITION_NONE; } } } 

==================================================== =================

 public class CardContainerFragment extends Fragment { private boolean cardFlipped = false; int current_index=0; static int pos = 0; public CardContainerFragment() { /*setHasOptionsMenu(true);*/ } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_card_container, container, false); LinearLayout ll = (LinearLayout)rootView.findViewById(R.id.layout); rootView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { flipCard(); } }); pos = getArguments().getInt("index"); getChildFragmentManager() .beginTransaction() .add(R.id.container, new CardFrontFragment().newInstance(pos)) .commit(); card_activity.tempCounter = card_activity.tempCounter+1; return rootView; } public void flipCard() { Fragment newFragment = null; CardFrontFragment cardFrontFragment = null; CardBackFragment cardBackFragment = null; if (cardFlipped) { newFragment = CardFrontFragment.newInstance(CardActivity.mViewPager.getCurrentItem()); } else { newFragment = cardBackFragment.newInstance(CardActivity.mViewPager.getCurrentItem()); } getChildFragmentManager() .beginTransaction() .setCustomAnimations( R.animator.card_flip_right_in, R.animator.card_flip_right_out, R.animator.card_flip_left_in, R.animator.card_flip_left_out) .replace(R.id.container, newFragment) .commit(); cardFlipped = !cardFlipped; } public static class CardBackFragment extends Fragment { public CardBackFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView_back = inflater.inflate(R.layout.fragment_card_back, container, false); TextView textview_back = (TextView)rootView_back.findViewById(R.id.card_back); textview_back.setMovementMethod(new ScrollingMovementMethod()); String text = getArguments().getString("back_text"); textview_back.setText(text); return rootView_back; } static CardBackFragment newInstance(int position) { CardBackFragment cardBackFragment = new CardBackFragment(); Bundle args = new Bundle(); String card_front_string = card_activity.arraylst.get(position); String text = card_activity.deck_map.get(card_front_string); args.putString("back_text", text); cardBackFragment.setArguments(args); return cardBackFragment; } } public static class CardFrontFragment extends Fragment { public CardFrontFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView_front = null; rootView_front = inflater.inflate(R.layout.fragment_card, container, false); TextView textview_front = (TextView)rootView_front.findViewById(R.id.card_front); String text = getArguments().getString("front_text"); textview_front.setText(text); return rootView_front; } static CardFrontFragment newInstance(int position) { CardFrontFragment cardFrontFragment = new CardFrontFragment(); Bundle args = new Bundle(); String card_front_string = card_activity.arraylst.get(position); String text = card_front_string +" \n \n + \n Tap now to flip this card."; args.putString("front_text", text); cardFrontFragment.setArguments(args); return cardFrontFragment; } } } 

Answer 2

As @ david-rawson says

Do not use the static fields of CardActivity.mViewPager. See https://developer.android.com/guide/components/fragments.html#CommunicatingWithActivity

The reason for this is that the ViewPager can / will create views of your fragments before they are displayed, to ensure that you get the smooth animation that people love ViewPagers. Thus, mViewPager calls several createView () functions at the same time, and while mViewPager has an index for .getCurrentItem() , which goes to CardContainer on the page being viewed.

It would be better for you to pass the CardContainerFragment String argument with the value for "completeText" that you want to display when it creates either CardBackFragment or CardFrontFragment .

Go through this one for more details.

Answer 3

You just need to set the data in the text view that is used in CardFrontFragment. Here, when the napkin onCreateView () CardContainerFragment ever occurs, is called. You add CardFrontFragment every time onCreateView () is called. you need to use the text view of CardFrontFragment instead of using the text view of activity.

Just replace CardActivity.tv.setText(current_page);

with textView.setText(current_page);

Make sure that the text image you used in CardFrontFragment is available at the class level.

you are using static snippets, so the textview should be static.

  private static TextView textView=null; 

Hope this works for you :)

Answer 4

Have you tried this:

  tv.post(new Runnable() { @Override public void run() { CardActivity.tv.setText(current_page); } }); 

Answer 5

I did something similar with my application, and I control the display of my TextView in OnCreateView with the switch body.

I tried to inject your code, but did not have all of your materials (e.g. custom animator).

Then you should try something like this:

 public class CardContainerFragment extends AppCompatActivity { private boolean cardFlipped = false; static TextView textview; /*public CardContainerFragment() { setHasOptionsMenu(true); }*/ @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.your_activity_name); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); // Create the adapter that will return a fragment for each of the three // primary sections of the activity. mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); // Set up the ViewPager with the sections adapter. /* The {@link ViewPager} that will host the section contents. */ ViewPager mViewPager = (ViewPager) findViewById(R.id.container); mViewPager.setAdapter(mSectionsPagerAdapter); mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { // This method will be invoked when a new page becomes selected. @Override flipCard(); @Override public void onPageSelected(int position) { } // This method will be invoked when the current page is scrolled @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { // Code goes here } // Called when the scroll state changes: // SCROLL_STATE_IDLE, SCROLL_STATE_DRAGGING, SCROLL_STATE_SETTLING @Override public void onPageScrollStateChanged(int state) { // Code goes here } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_welcome, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); //noinspection SimplifiableIfStatement if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } /** * A placeholder fragment containing a simple view. */ public static class PlaceholderFragment extends Fragment { /** * The fragment argument representing the section number for this * fragment. */ private static final String ARG_SECTION_NUMBER = "section_number"; public PlaceholderFragment() { } /** * Returns a new instance of this fragment for the given section * number. */ public static PlaceholderFragment newInstance(int sectionNumber) { PlaceholderFragment fragment = new PlaceholderFragment(); Bundle args = new Bundle(); args.putInt(ARG_SECTION_NUMBER, sectionNumber); fragment.setArguments(args); return fragment; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { //Initializing data Context context = getContext(); View rootView = inflater.inflate(R.layout.fragment_card, container, false); TextView textView = (TextView) rootView.findViewById(R.id.txtView); int fragment = getArguments().getInt(ARG_SECTION_NUMBER); switch (fragment) { case 1: //front card String card_front_string = card_activity.arraylst.get(CardActivity.mViewPager.getCurrentItem()); Log.e("current Item",CardActivity.mViewPager.getCurrentItem()+""); String complete_text = card_front_string +" \n \n + \n Tap now to flip this card."; textview.setText(complete_text); getChildFragmentManager() .beginTransaction() .add(R.id.container, new CardFrontFragment()) .commit(); Message msg = handler.obtainMessage(); msg.arg1 = 1; handler.sendMessage(msg); return rootView; case 2: //back card TextView textview = (TextView)rootView.findViewById(R.id.card_back); textview.setMovementMethod(new ScrollingMovementMethod()); String card_front_string = card_activity.arraylst.get(CardActivity.mViewPager.getCurrentItem()); String deck_data = card_activity.deck_map.get(card_front_string); textview.setText(deck_data); getChildFragmentManager() .beginTransaction() .add(R.id.container, new CardFrontFragment()) .commit(); Message msg = handler.obtainMessage(); msg.arg1 = 1; handler.sendMessage(msg); return rootView; default: return rootView; } } } final Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { int page = CardActivity.mViewPager.getCurrentItem(); int page_index = page+1; String current_page = page_index + " of " + card_activity.deck_map.size(); CardActivity.tv.setText(current_page); super.handleMessage(msg); } }; public void flipCard() { Message msg = handler.obtainMessage(); msg.arg1 = 1; handler.sendMessage(msg); getChildFragmentManager() .beginTransaction() .setCustomAnimations( R.animator.card_flip_right_in, R.animator.card_flip_right_out, R.animator.card_flip_left_in, R.animator.card_flip_left_out) .replace(R.id.container, newFragment) .commit(); } /** * A {@link FragmentPagerAdapter} that returns a fragment corresponding to * one of the sections/tabs/pages. */ public class SectionsPagerAdapter extends FragmentPagerAdapter { SectionsPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { // getItem is called to instantiate the fragment for the given page. // Return a PlaceholderFragment (defined as a static inner class below). return PlaceholderFragment.newInstance(position + 1); } @Override public int getCount() { // Show 2 total pages. return 2; } @Override public CharSequence getPageTitle(int position) { switch (position) { case 0: return "SECTION 1"; case 1: return "SECTION 2"; } return null; } } 

A TextView is displayed on your page, and when you select a change, the contents of your text comment will be changed.