Develop Reference

viewpager is not showing any fragment

I have created two fragments in my app. I want to use these fragments in viewpager. This is my CustomAdapter for Viewpager:
public class CustomSwipeAdapter extends FragmentStatePagerAdapter {
public CustomSwipeAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position)
{
case 0:
return new fragmentComment();
case 1:
return new fragment_Rating();
default:
return new fragmentComment();
}
}
#Override
public int getCount() {
return 2;
}
}
And this is my Viewpager:
pager=(ViewPager)findViewById(R.id.view_pager);
FragmentActivity fm=new FragmentActivity();
CustomSwipeAdapter adapter=new CustomSwipeAdapter(fm.getSupportFragmentManager());
pager.setAdapter(adapter);
But when i run my app,nothing is shown in viewpager.
Can Anyone help?

You forgot
adapter.addFragment(new fragmentComment(), "FragmentComment");
adapter.addFragment(new fragment_Rating(), "FragmentRating");

tab fragment not calling OnCreateView switching from tab1 to tab0?

There is three tab fragment in my app when tab at index 0 onCreate called when app launch, tab ta index 1 onCreateView method not called. I need to update UI in tab 1 onCreate method. How do i resolve this kind of issue.
code:
private void setupViewPager(ViewPager viewPager) {
adapter.addFragment(new Users());
adapter.addFragment(new FavouriteUsers());
adapter.addFragment(new Recent());
viewPager.setAdapter(adapter);
}
page Adapter code:
public class UserPagerAdapter extends FragmentStatePagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
public UserPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment) {
mFragmentList.add(fragment);
}
}

Try to Use getChildFragmentManager() to initilize your UserPagerAdapter
UserPagerAdapter adapter = new UserPagerAdapter(getChildFragmentManager())
if this doesn't work try changing FragmentStatePagerAdapter to FragmentPagerAdapter.

implement your getItem(int position) like this.
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
Users tab1 = new Users();
return tab1;
case 1:
FavouriteUsers tab2 = new FavouriteUsers();
return tab2;
case 2:
Recent tab3 = new Recent();
return tab3;
default:
return null;
}
}
and in your tab activity call adapter like this
final UserPagerAdapter adapter = new UserPagerAdapter
(getSupportFragmentManager());
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});

Android - ViewPager third tab has not shown

i have a viewPager that contains 3 tabs fragments.
the first and the second fragments works fine but when i sweep to the third tab
i do not see him.
the third tab has shown only when the activity with the viewPager has reload(move to another activity and return).
my code:
private void setupViewPager(ViewPager viewPager) {
adapter = new PagerAdapter(getSupportFragmentManager());
adapter.addFragment(new Fragment1(), Constants.TAB_0);
adapter.addFragment(new Fragment2(), Constants.TAB_1);
adapter.addFragment(new Fragment3(), Constants.TAB_2);
viewPager.setAdapter(adapter);
viewPager.setOffscreenPageLimit(3);
}
pager adapter:
public class PagerAdapter extends FragmentPagerAdapter {
/*
* Arraylist used to contain the fragments
* and contain fragments title's
*/
private final List<Fragment> fragmentList = new ArrayList<>();
private final List<String> fragmentTitleList = new ArrayList<>();
public PagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
#Override
public int getCount() {
return fragmentList.size();
}
//Adds the fragment and it's title. Called in MainActivity
public void addFragment(Fragment fragment, String title) {
fragmentList.add(fragment);
fragmentTitleList.add(title);
}
//Retrieves the title of the tab
#Override
public CharSequence getPageTitle(int position) {
return fragmentTitleList.get(position);
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
}

Here is my adapter, on getItem I set the fragment object to the Fragment activity.
public class SectionPagerAdapter extends FragmentPagerAdapter {
Fragment fragment;
public SectionPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
if (position == 0){
fragment = new FragmentOne();
}
else if (position == 1){
fragment = new FragmentTwo();
}
else if (position == 2){
fragment = new FragmentThree();
}
return fragment;
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "name one";
case 1:
return "name two";
case 2:
return "name three";
}
return null;
}
}
Then in my main activity I call it like so:
ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
SectionPagerAdapter sectionPagerAdapter = new SectionPagerAdapter(getSupportFragmentManager());
mViewPager.setAdapter(sectionPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
Try replacing your code with above and let me know if it helps!

USE new PagerAdapter(getChildSupportFragmentManager());instead of getSupportFragmentManager()
Try this one !!

How to show fragment in android

I am using ViewPager to create 3 Fragment on Activity1,
this is my viewPager adapter :
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
public ViewPagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
Fragment1 tab1 = new Fragment1();
return tab1;
case 1:
Fragment2 tab2 = new Fragment2();
return tab2;
case 2:
Fragment3 tab3 = new Fragment3();
return tab3;
default:
return null;
}
}
#Override
public int getCount() {
return mNumOfTabs;
}
}
this is Activity :
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_1);
TabLayout tab_layout = (TabLayout) findViewById(R.id.tab_layout);
tab_layout.addTab(tab_layout.newTab().setText("Frag1"));
tab_layout.addTab(tab_layout.newTab().setText("Frag2"));
tab_layout.addTab(tab_layout.newTab().setText("Frag3"));
final ViewPager view_pager = (ViewPager) findViewById(R.id.viewpager);
final ViewPagerAdapter adapter = new ViewPagerAdapter
(getSupportFragmentManager(), tab_layout.getTabCount());
view_pager.setAdapter(adapter);
view_pager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tab_layout));
tab_layout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
view_pager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
When Activity1 is open it show Fragment1 . But I want to show Fragment2 or Fragment3 instead .
How I can to do that?

Add this line after viewpager.setAdapter(adapter); :
viewPager.setCurrentItem(index);
Index is depending on you , how many fragments you have. tabLayout.getTabCount(); will return you tab count. But index is starting from 0.
If you have 3 Fragment and want to show third Fragment you must use viewPager.setCurrentItem(2);

Set current position of viewpager to your desired possition which is 2 or 3 in your case.
new Handler().post(new Runnable() {
#Override
public void run() {
mViewPager.setCurrentItem(desiredPos);
}
});
seee more
Android ViewPager setCurrentItem not working after onResume

properly remove fragments from FragmentStatePagerAdapter

hey guys i implemented a tab layout(an action bar with tabs) , basically it is made of using pagerAdapter and FragmentStatePagerAdapter below is my code :
public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
public PagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
TabFragment1 tab1 = new TabFragment1();
return tab1;
case 1:
TabFragment2 tab2 = new TabFragment2();
return tab2;
case 2:
TabFragment3 tab3 = new TabFragment3();
return tab3;
case 3:
TabFragment4 tab4 = new TabFragment4();
return tab4;
case 4:
TabFragment5 tab5 = new TabFragment5();
return tab5;
default:
return null;
}
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
// TODO Auto-generated method stub
super.destroyItem(container, position, object);
FragmentManager manager = ((Fragment) object).getFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.remove((Fragment) object);
trans.commit();
}
#Override
public int getCount() {
return mNumOfTabs;
}}
my mainActivty:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("Tab1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab2"));
tabLayout.addTab(tabLayout.newTab().setText("Tab3"));
tabLayout.addTab(tabLayout.newTab().setText("Tab4"));
tabLayout.addTab(tabLayout.newTab().setText("Tab5"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
final PagerAdapter adapter = new PagerAdapter
(getSupportFragmentManager(), tabLayout.getTabCount());
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
now i want to remove the tabs(fragments) and for that am just removing them from here
tabLayout.addTab(tabLayout.newTab().setText("Tab1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab2"));
tabLayout.addTab(tabLayout.newTab().setText("Tab3"));
tabLayout.addTab(tabLayout.newTab().setText("Tab4"));
if (condition == true){ // do nothing which means don't add the fragment }
else {
tabLayout.addTab(tabLayout.newTab().setText("Tab5")); }
and is working but not as it supposed to , even after removing the the tab from here tabLayout.addTab(tabLayout.newTab().setText("Tab5")); the fragments are still there and actively performing their task , i want to shut them completely , am new in android so have no idea about this that its a good approach or not guys is it enough or not please let me know any guidance will be so helpful for me