Develop Reference

Clear data of fragments in ViewPager with each swipe

#Override
public void onViewDetachedFromWindow(#NonNull FragmentViewHolder holder) {
super.onViewDetachedFromWindow(holder);
}
I have many independent EditText with different id in each fragments of viewpager. For each swipe I want to clear these EditText and make them default.
I can clear text using:
holder.itemview.findViewById(R.id.first).setText("something");
but it won't a clear text.
What should I do?
Edit: whole testing Code:
I prepare a test fragment. When I click button,it changes text in current fragment. When I swipe to second fragment, It should be cleared or changed into its default value at xml.
TestFragment
public class TestFragment extends Fragment {
private TestViewModel mViewModel;
private ViewPager2 mViewPager;
private Button btnTest;
public static TestFragment newInstance() {
return new TestFragment();
}
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.test_fragment, container, false);
btnTest=(Button)view.findViewById(R.id.etTest);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mViewModel = ViewModelProviders.of(this).get(TestViewModel.class);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mViewPager = view.findViewById(R.id.myPager);
mViewPager.setSaveFromParentEnabled(false);
mViewPager.setOffscreenPageLimit(1);
mViewPager.setAdapter(new ViewPagerAdapter(getChildFragmentManager(),getLifecycle()));
TabLayout tabLayout = view.findViewById(R.id.tabs);
new TabLayoutMediator(tabLayout, mViewPager,
new TabLayoutMediator.TabConfigurationStrategy() {
#Override
public void onConfigureTab(#NonNull TabLayout.Tab tab, int position) {
tab.setText(((ViewPagerAdapter)(mViewPager.getAdapter())).mFragmentNames[position]);//Sets tabs names as mentioned in ViewPagerAdapter fragmentNames array, this can be implemented in many different ways.
}
}
).attach();
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
Fragment current=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(tab.getPosition());//clear data here or below
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}});
btnTest.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
int cur=((ViewPagerAdapter)(mViewPager.getAdapter())).getCurrentPos();
switch (cur){
case 0:
Fragment current=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(0);
TextView tF= current.getView().findViewById(R.id.first);
tF.setText("Clicked while 1");
break;
case 1:
Fragment current2=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(1);
TextView tF2= current2.getView().findViewById(R.id.second);
tF2.setText("Clicked while 2");
break;
}
}
});
}
public class ViewPagerAdapter extends FragmentStateAdapter {
private int currentPos;
private final Fragment[] mFragments = new Fragment[] {
new FirstFragment(),
new SecondFragment(),
};
public final String[] mFragmentNames = new String[] {
"First",
"Second"
};
public ViewPagerAdapter(#NonNull FragmentManager fragmentManager, #NonNull Lifecycle lifecycle) {
super(fragmentManager, lifecycle);
}
#Override
public void onViewDetachedFromWindow(#NonNull FragmentViewHolder holder) {
super.onViewDetachedFromWindow(holder);
if(currentPos!=0){
TextView textView =(TextView)holder.itemView.findViewById(R.id.first);//clear data here or up
}
}
#Override
public int getItemCount() {
return mFragments.length;
}
#Override
public long getItemId(int position) {
this.setCurrentPos(position);
return super.getItemId(position);
}
public int getCurrentPos() {
return currentPos;
}
public void setCurrentPos(int currentPos) {
this.currentPos = currentPos;
}
#NonNull
#Override
public Fragment createFragment(int position) {
return mFragments[position];
}
}}
I can handle on onViewDetachedFromWindow or onTabUnselected. Both can change view.
First Fragment
public class FirstFragment extends Fragment {
private View mLeak;
private TextView tvTest;
public FirstFragment() {
}
public static FirstFragment newInstance(String param1, String param2) {
FirstFragment fragment = new FirstFragment();
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mLeak = inflater.inflate(R.layout.fragment_first, container, false);
tvTest=mLeak.findViewById(R.id.first);
return mLeak;
}
#Override
public void onDetach() {
super.onDetach();
mLeak=null;
}}

Approach 1:
Set this line on your viewpager :
viewPager.setOffscreenPageLimit(1);
This will simply refresh each fragment again when it's loaded.
Approach 2:
Create an interface and implement it on each fragment. In your activity/fragment where viewpager is defined, use "addOnPageChangeListener" on viewpager, and when the different page is selected, simply use the interface to get back the fragment instance and call the required methods in the fragment, to clear/change the text.
Code :
//Your Activity
class HomeActivity extends Activity{
...Methods...
public void setUpViewpager(){
//setup your viewpager
viewpager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
#Override
public void onPageSelected(int position) {
ChangeText fragment = (ChangeText) viewpager.getFragment(position);
fragment.changeText();
}
#Override
public void onPageScrollStateChanged(int state) {}
});
}
interface ChangeText{
void changeText();
}
}
//Your fragment
class FirstFragment extends Fragment implements HomeActivity.ChangeText{
...Methods...
public void changeText(){
//change the textview text here
}
}
class SecondFragment extends Fragment implements HomeActivity.ChangeText{
...Methods...
public void changeText(){
//change the textview text here
}
}

Call a method when sliding from one fragment to another

I have 2 Tabs as fragments in a ViewPager in an Activity
When I tap the second tab in the layout, the OnTabUnselected method works.
However, when I slide the screen from one tab to another, the method isn't called.
How do I achieve this calling of method by both means "Tapping as well as in a Sliding Gesture"
My Activity class is:
public class OrderActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private FloatingActionButton printAction;
ViewPagerAdapter adapter;
private Boolean exit = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_icon_text_tabs);
TypefaceUtil.overrideFont(getApplicationContext(), "serif", "fonts/opensans.tff");
//TypefaceUtil.overrideFont(getApplicationContext(), "arial", "fonts/opensans.tff");
this.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
//setupTabIcons();
printAction = (FloatingActionButton) findViewById(R.id.float_print);
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
Toast.makeText(getApplicationContext(),"onTabSelected",Toast.LENGTH_LONG).show();
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
String ac = null;
int pos = viewPager.getCurrentItem();
Fragment activeFragment = adapter.getItem(pos);
if(pos==0){
ac= ((PersonalDetailFragment)activeFragment).getXmlValue();
}
Toast.makeText(getApplicationContext(),ac,Toast.LENGTH_LONG).show();
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
Toast.makeText(getApplicationContext(),"onTabReselected",Toast.LENGTH_LONG).show();
}
});
}
private void setupViewPager(ViewPager viewPager) {
adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new PersonalDetailFragment(), "Personal");
adapter.addFrag(new OrderItemsFragment(), "Invoice");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
Fragment A:
public class FragmentA extends Fragment {
private EditText custName;
public PersonalDetailFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.personal_detail_fragment, container, false);
custName = (EditText) view.findViewById(R.id.customerContactEditText);
return view;
}
public String getXmlValue(){
return custName.getText().toString();
}
}
Fragment B:
public class FragmentB extends Fragment {
private EditText contactNo;
public PersonalDetailFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.personal_detail_fragment, container, false);
contactNo = (EditText) view.findViewById(R.id.customerContactEditText);
return view;
}
}

You can use the ViewPager.addOnPageChangeListener() method to register a listener and get notified about changing the current tab with a pager swipe.
There is a really nice tutorial here.

In your fragment you can use a method named setVisibilityHint that is called every time the visibility of the fragment has been changed. There is a boolean parameter that can be true or false depending if the fragment is visible or not
#Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
}

View pager skipping to irregular position when I click button in second fragment android?

I am using view pager in activity and the sequence is - when I click the next button in first page, it should go to the second page. If I click the button in second page, it should go to third and so on. But my current app is behaving weird, i.e, When I click next button in second page, it goes to fourth page. Once again when I click first button in first page, it jumps to third page and so on..
Here is code.
public class ViewPagerActivity extends AppCompatActivity {
private ViewPager pager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.viewpager_act);
setViewPager();
/*pager.setPageTransformer(true, new ZoomPageTransformer());
pager.setAdapter(new MyViewPagerAdapter(getSupportFragmentManager()));
pager.post(new Runnable() {
#Override
public void run() {
pager.setCurrentItem(position); //don't know how to use this from fragment
}
});*/
}
private void setViewPager() {
pager = (ViewPager) findViewById(R.id.viewPager);
FragmentManager fm = getSupportFragmentManager();
ViewPagerAdapter adapter = new ViewPagerAdapter(fm);
pager.setAdapter(adapter);
}
public void setCurrentItem(int selectedPosition) {
pager.setCurrentItem(selectedPosition, true);
}
private class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager supportFragmentManager) {
super(supportFragmentManager);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return FirstPager.newInstance();
case 1:
return SecondPager.newInstance();
case 2:
return ThirdPager.newInstance();
case 3:
return FourthPager.newInstance();
case 4:
return FifthPager.newInstance();
case 5:
return SixthPager.newInstance();
default:
return null;
}
}
#Override
public int getCount() {
return 6;
}
}
FirstPager:
public class FirstPager extends Fragment {
private ImageView slideArrow;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.first_pager, container, false);
return v;
}
public static FirstPager newInstance() {
FirstPager fragment = new FirstPager ();
return fragment;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
initUI();
}
private void initUI() {
slideArrow = (ImageView) getActivity().findViewById(R.id.next_arrow);
slideArrow.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
((ViewPagerActivity)getActivity()).setCurrentItem (1);
}
});
}
}
Similarly in other fragments, I gave currentItem as 2,3,4,5 and 6. But it’s position behavior is not correct.
I referred some post but how in my case, how I will apply for a method to pass from fragment to make the position to work correctly?

I think the best approach would be this:
viewPager.setCurrentItem(viewPager.getCurrentItem() + 1);

slideArrow = (ImageView) getActivity().findViewById(R.id.next_arrow);
Are you sure, you're calling this correctly? You're not.
You're calling findViewById of the arrow inside your activity. A ViewPager works by loading this page, and pre-loading next and previous pages for smooth swipe. And when you click the button on your 1st page, the last loaded page's (in your case 2nd page's) button click event gets called.
You must use the arrow button in each of your fragments
You can do something like this:
public class FirstPager extends Fragment {
private ImageView slideArrow;
View v;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
v = inflater.inflate(R.layout.first_pager, container, false);
return v;
}
public static FirstPager newInstance() {
FirstPager fragment = new FirstPager ();
return fragment;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
initUI();
}
private void initUI() {
slideArrow = (ImageView) v.findViewById(R.id.next_arrow); // Note the difference in this line.
slideArrow.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
((ViewPagerActivity)getActivity()).setCurrentItem (1);
}
});
}
}

You can do two things here:
Firstly,Your viewpager has a override method onPageSelected() which return the select page positon. using this poistion element get the view and bind your button there and write listener there itself and write viewpager.setCurrentItem(i++); //if i is ur current position,but be sure to check if it is the last item.
secondly,you hold the position of the current fragment and
((ViewPagerActivity)getActivity()).setCurrentItem (next_frag_pos);

This code try working perfect.
public class ViewPagerActivity extends FragmentActivity {
private ViewPager pager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.viewpager_act);
setViewPager();
/*pager.setPageTransformer(true, new ZoomPageTransformer());
pager.setAdapter(new MyViewPagerAdapter(getSupportFragmentManager()));
pager.post(new Runnable() {
#Override
public void run() {
pager.setCurrentItem(position); //don't know how to use this from fragment
}
});*/
}
private void setViewPager() {
pager = (ViewPager) findViewById(R.id.viewPager);
FragmentManager fm = getSupportFragmentManager();
ViewPagerAdapter adapter = new ViewPagerAdapter(fm);
pager.setAdapter(adapter);
}
public void setCurrentItem(int selectedPosition) {
pager.setCurrentItem(selectedPosition, true);
}
private class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager supportFragmentManager) {
super(supportFragmentManager);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new FirstPager();
case 1:
return new SecondPager();
case 2:
return new ThirdPager();
case 3:
return new FourthPager();
case 4:
return new FifthPager();
case 5:
return new SixthPager();
default:
return null;
}
}
#Override
public int getCount() {
return 6;
}
}
}

Using viewpager with radiogroup to switch between fragments

I have a viewpager with swipeable fragments and also a radiogroup that shows which view is selected. When I start the application, the first radiobutton is not selected, it is only selected when I swipe another view and get back. I am a beginner, so please share your knowledge. Here's my code:
Viewpager Adapter:
public class ViewPagerAdapter extends FragmentPagerAdapter {
public static int int_items = 3;
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new WelcomeOneFragment();
case 1:
return new WelcomeTwoFragment();
case 2:
return new WelcomeThreeFragment();
}
return null;
}
#Override
public int getCount() {
return int_items;
}
Fragment with the radiogroup:
public class TabFragment extends BaseFragment implements ViewPager.OnPageChangeListener, View.OnClickListener {
public static ViewPager mViewPager;
private Button mButtonMassage;
private RadioGroup mRadioGroup;
public static TabFragment newInstance() {
return new TabFragment();
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_tab, container, false);
initUi(rootView);
return rootView;
}
#Override
public void initUi(View rootView) {
mRadioGroup = (RadioGroup) rootView.findViewById(R.id.radio_group);
mViewPager = (ViewPager) rootView.findViewById(R.id.view_pager);
mButtonMassage = (Button) rootView.findViewById(R.id.buttonMassage);
initListeners();
}
#Override
public void initListeners() {
mButtonMassage.setOnClickListener(this);
mViewPager.addOnPageChangeListener(this);
initData();
}
#Override
public void initData() {
mViewPager.setAdapter(new ViewPagerAdapter(getChildFragmentManager()));
mViewPager.setCurrentItem(0);
}
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.buttonMassage:
Intent i = new Intent(getActivity(), MassageActivity.class);
startActivity(i);
break;
default:
break;
}
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
mRadioGroup.check(mRadioGroup.getChildAt(position).getId());
}
#Override
public void onPageScrollStateChanged(int state) {
}
}

just call this
mRadioGroup.check(mRadioGroup.getChildAt(0).getId());
after
mViewPager.setCurrentItem(0);
as listner will not callup in starting and you have to set it for manually after setting adapter to viewpager
hope it will work for you!! :)

This is a pretty common issue with ViewPager. onPageSelected is not called upon start, so I would just call:
mRadioGroup.check(mRadioGroup.getChildAt(0).getId());
In your initUi() method.

Android ViewPager, switching from fragment to another fragment

I have a viewpager with 2 pages, on each fragment i put a button to switching fragment,
but if i change orientation switching doesn't work.
For switching fragment I using my OnChangePageButtonClick interface
Why is this happening?
ViewPager Activity:
public class ViewPagerMusic extends FragmentActivity implements OnChangePageButtonClick {
private ViewPager vp;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view_pager_music);
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(super.getSupportFragmentManager(), fragments);
vp = (ViewPager)findViewById(R.id.viewpager);
vp.setAdapter(viewPagerAdapter);
}
private class ViewPagerAdapter extends FragmentStatePagerAdapter {
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch(position) {
case 0:
MainPage mainPage = new MainPage();
mainPage.setOnChengeButtonListener(ViewPagerMusic.this);
return mainPage;
case 1:
PlaylistPage playlistPage = new PlaylistPage();
playlistPage.setOnChengeButtonListener(ViewPagerMusic.this);
return playlistPage;
}
return null;
}
#Override
public int getCount() {
return 2;
}
}
#Override
public void selectPage(int page) {
vp.setCurrentItem(page);
}
}
my Frgamnets:
public class MainPage extends Fragment {
public MainPage() {
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.music_main_page, container, false);
ImageButton btnPlaylist = (ImageButton)v.findViewById(R.id.btnGoPlaylist2);
btnPlaylist.setOnClickListener(onButtonListener);
return v;
}
private OnClickListener onButtonListener = new OnClickListener() {
#Override
public void onClick(View view) {
onChangePageButtonClick.selectPage(1);
}
};
public void setOnBackButtonListener(OnChangePageButtonClick onChangePageButtonClick) {
this.onChangePageButtonClick = onChangePageButtonClick;
}
private OnChangePageButtonClick onChangePageButtonClick;
}
Playlist fragment is similar to MainPage fragment.

Your fragments are storing a reference to the ViewPagerMusic activity. However, after rotation, the activity is destroyed and recreated, so the fragments now contain a reference to the old activity.
Instead of storing a reference to the activity, you can call the activity's method from the fragment like this:
((ViewPagerMusic) getActivity()).selectPage(1);

just create this method in your view pager
#Override
public void selectPage(int page) {
vp.setCurrentItem(page);
}
and then call this in your onclick method
((ViewPagerMusic) getActivity()).selectPage(1);