Develop Reference

Add icon in my tabbed activity (android studio)

Here the code:
SectionsPagerAdapter:
public class SectionsPagerAdapter extends FragmentPagerAdapter {
#StringRes
private static final int[] TAB_TITLES = new int[]{R.string.tab_text_1, R.string.tab_text_2, R.string.tab_text_3, R.string.tab_text_4};
private final Context mContext;
public SectionsPagerAdapter(Context context, FragmentManager fm) {
super(fm);
mContext = context;
}
#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);
Fragment fragment = null;
switch(position){
case 0:
fragment = new Fragment1();
break;
case 1:
fragment = new Fragment2();
break;
case 2:
fragment = new Fragment3();
break;
case 3:
fragment = new Fragment4();
break;
}
return fragment;
}
#Nullable
#Override
public CharSequence getPageTitle(int position) {
return mContext.getResources().getString(TAB_TITLES[position]);
}
#Override
public int getCount() {
// Show 4 total pages.
return 4;
}
}
PlaceholderFragment:
public class PlaceholderFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
private PageViewModel pageViewModel;
public static PlaceholderFragment newInstance(int index) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle bundle = new Bundle();
bundle.putInt(ARG_SECTION_NUMBER, index);
fragment.setArguments(bundle);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
pageViewModel = new ViewModelProvider(this,
new ViewModelProvider.NewInstanceFactory()).get(PageViewModel.class);
int index = 1;
if (getArguments() != null) {
index = getArguments().getInt(ARG_SECTION_NUMBER);
}
pageViewModel.setIndex(index);
}
#Override
public View onCreateView(
#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_main, container, false);
final TextView textView = root.findViewById(R.id.section_label);
pageViewModel.getText().observe(this, new Observer<String>() {
#Override
public void onChanged(#Nullable String s) {
textView.setText(s);
}
});
return root;
}
Using tabbed activity from android studio example whit legacy android studio libraries
I would like to add icons above the writing, please write some examples thanks.

To add an icon above the text in TabLayout you can use the attribute android:icon of TabItem. More information can be found in the Material Design Documentation. The app:tabIconTint is responsible to set the icon tint color.
An a example in xml is like below:
<com.google.android.material.tabs.TabLayout
android:id="#+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/darker_gray"
app:tabIndicatorColor="#android:color/holo_orange_dark"
app:tabIndicatorHeight="2dp"
app:tabMode="fixed"
app:tabIconTint="#android:color/white"
app:tabTextColor="#android:color/white">
<com.google.android.material.tabs.TabItem
android:id="#+id/tabItem1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:icon="#drawable/ic_home_24dp"
android:text="Tab1" />
<com.google.android.material.tabs.TabItem
android:id="#+id/tabItem2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:icon="#drawable/ic_chat_24dp"
android:text="Tab2" />
<com.google.android.material.tabs.TabItem
android:id="#+id/tabItem3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:icon="#drawable/ic_create_24dp"
android:text="Tab3" />
</com.google.android.material.tabs.TabLayout>
or Programmatically:
TabLayout tabLayout = findViewById(R.id.tabLayout);
tabLayout.getTabAt(0).setIcon(R.drawable.ic_home_24dp);
Result:

Android ViewPager doesn't show Fragment

I'm trying to let my ViewPager to show my Fragments, however, it doesn't seem to do the work. All it does is just not showing anything, not even a height. Can someone tell me what step am I missing? thanks
main_activity.xml:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorBackground">
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/bottomNavigation" />
<com.aurelhubert.ahbottomnavigation.AHBottomNavigation
android:id="#+id/bottomNavigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom" />
</android.support.design.widget.CoordinatorLayout>
MainActivity.java:
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
AHBottomNavigation bottomNavigation;
ViewPager viewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bottomNavigation = (AHBottomNavigation) findViewById(R.id.bottomNavigation);
viewPager = (ViewPager) findViewById(R.id.viewpager);
ViewPagerAdapter pagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
// Buttom Navigation
// Add items
AHBottomNavigationItem item1 = new AHBottomNavigationItem("Rooms", R.drawable.ic_chatboxes);
AHBottomNavigationItem item2 = new AHBottomNavigationItem("User", R.drawable.ic_contact_outline);
bottomNavigation.addItem(item1);
bottomNavigation.addItem(item2);
// Customize Buttom Navigation
bottomNavigation.setTitleState(AHBottomNavigation.TitleState.ALWAYS_SHOW);
// Set colors
bottomNavigation.setAccentColor(ContextCompat.getColor(this, R.color.colorAccent));
bottomNavigation.setInactiveColor(ContextCompat.getColor(this, R.color.colorTabDefault));
// Set background color
bottomNavigation.setDefaultBackgroundColor(ContextCompat.getColor(this, R.color.colorBackground));
bottomNavigation.setTranslucentNavigationEnabled(true);
// Viewpager setup
pagerAdapter.addFragment(new Rooms(), "Rooms");
pagerAdapter.addFragment(new User(), "User");
viewPager.setAdapter(pagerAdapter);
viewPager.setCurrentItem(bottomNavigation.getCurrentItem());
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
bottomNavigation.setCurrentItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
bottomNavigation.setOnTabSelectedListener(new AHBottomNavigation.OnTabSelectedListener() {
#Override
public boolean onTabSelected(int position, boolean wasSelected) {
viewPager.setCurrentItem(position, true);
return true;
}
});
}
ViewPagerAdapter.java:
public class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
private Fragment currentItem;
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 addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
#Override
public void setPrimaryItem(ViewGroup container, int position, Object object) {
if (getCurrentItem() != object) {
currentItem = ((Fragment) object);
}
super.setPrimaryItem(container, position, object);
}
public Fragment getCurrentItem() {
return currentItem;
}
}

fragment disappears

I have a fragment alertsfragment.java , which has a grid view layout, when I open that , it works normally , but as soon I swipe between other tabs ,it vanishes away .
to explain more , I have an activity tab layout which has a tab on the bottom , and its first tab opens two fragments alertsfragment and friendsfragment,
I am including the code and the screenshot for simplification.
staring with mapfragment which contains two fragment alert frag and friends frag
mapfragment.java
public class MapFragment extends Fragment{
TabLayout tabLayout;
ViewPager viewPager;
public MapFragment()
{
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View ROOTView =inflater.inflate(R.layout.mapfragment,container,false);
viewPager = (ViewPager)ROOTView.findViewById(R.id.viewpager2);
setupViewPager(viewPager);
tabLayout = (TabLayout)ROOTView.findViewById(R.id.tabs);
//viewPager.setOffscreenPageLimit(2);
tabLayout.setupWithViewPager(viewPager);
return ROOTView;
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(this.getFragmentManager());
adapter.addFragment(new FriendsFragment(), "FRIENDS");
adapter.addFragment(new AlertsFragment(), "Alerts");
setRetainInstance(true);
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 addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
alertsfragment.java
public class AlertsFragment extends Fragment{
GridView grid;
final String[] name = {
"Google",
"Github",
"Instagram",
"Facebook",
} ;
final String[] status = {
"Google",
"Github",
"Instagram",
"Facebook",
} ;
final String[] place = {
"Google",
"Github",
"Instagram",
"Facebook",
} ;
final int[] imageId = {
R.drawable.logo,
R.drawable.logo,
R.drawable.logo,
R.drawable.logo,
};
public AlertsFragment()
{
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View alertsfrag =inflater.inflate(R.layout.alertsfragments,container,false);
grid=(GridView) alertsfrag.findViewById(R.id.grid);
CustomGrid adapter = new CustomGrid(getActivity(), name,status,place,imageId);
grid=(GridView)alertsfrag.findViewById(R.id.grid);
grid.setAdapter(adapter);
grid.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(getActivity(), "You Clicked at " +name[+ position], Toast.LENGTH_SHORT).show();
}
});
return alertsfrag;
}
}
its customadapter
public class CustomGrid extends BaseAdapter{
private Context mContext;
private final String[] name;
private final String[] status;
private final String[] place;
private final int[] Imageid;
public CustomGrid(Context c,String[] name,String[] status,String[] place,int[] Imageid ) {
mContext = c;
this.Imageid = Imageid;
this.name = name;
this.status = status;
this.place = place;
}
#Override
public int getCount() {
// TODO Auto-generated method stub
return name.length;
// return status.length;
// return place.length;
}
#Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
#Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
View grid;
LayoutInflater inflater = (LayoutInflater) mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
grid = new View(mContext);
grid = inflater.inflate(R.layout.grid_single, null);
TextView textView = (TextView) grid.findViewById(R.id.grid_text);
TextView textView1 = (TextView) grid.findViewById(R.id.grid_text1);
TextView textView2 = (TextView) grid.findViewById(R.id.grid_text2);
ImageView imageView = (ImageView)grid.findViewById(R.id.grid_image);
textView.setText(name[position]);
textView1.setText(status[position]);
textView2.setText(place[position]);
imageView.setImageResource(Imageid[position]);
} else {
grid = (View) convertView;
}
return grid;
}
}
its XML
alertsfrag.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".AlertsFragment" >
<GridView
android:layout_marginTop="60dp"
android:numColumns="2"
android:gravity="center"
android:columnWidth="100dp"
android:stretchMode="columnWidth"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/grid"
/>
</LinearLayout>
mainTabLayout
TabLayout.java
public class Bottom_Tabs_Activity extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
private int[] tabIcons = {
R.drawable.ic_friends,
R.drawable.ic_map,
R.drawable.ic_status,
R.drawable.ic_chat,
R.drawable.ic_profile
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.tabs);
viewPager = (ViewPager) findViewById(R.id.viewpager);
if (viewPager != null)
setupViewPager(viewPager);
else {
Log.e("test", "i am null");
}
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
setupTabIcons();
}
private void setupTabIcons() {
tabLayout.getTabAt(0).setIcon(tabIcons[0]);
tabLayout.getTabAt(1).setIcon(tabIcons[1]);
tabLayout.getTabAt(2).setIcon(tabIcons[2]);
tabLayout.getTabAt(3).setIcon(tabIcons[3]);
tabLayout.getTabAt(4).setIcon(tabIcons[4]);
}
private void setupViewPager(ViewPager viewPager)
{
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new MapFragment(),"MAPS");
adapter.addFrag(new PeopleFragment(),"PEOPLE");
adapter.addFrag(new HomeFragment(),"HOME");
adapter.addFrag(new ChatFragment(),"CHAT");
adapter.addFrag(new ProfileFragment(),"PROFILE");
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 null to display only the icon
return null;
}
}
}
TabLayout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent">
<LinearLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/main_content"
android:orientation="vertical"
android:weightSum="1"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".9"
app:layout_behavior="#string/appbar_scrolling_view_behavior"/>
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
app:tabMode="fixed"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".1"
android:background="#000000"
app:tabIndicatorColor="#ff1232"
app:tabGravity="fill"
/>
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_gravity="bottom"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
>
</android.support.design.widget.AppBarLayout>
</LinearLayout>
</LinearLayout>
Screenshots
Before and after
any kind of help would be appreciated:)

needed to use getChildFragmentManager() instead of getFragmentManager() for placing and managing Fragments inside of a Fragment.
see mapfragment.java , there I used this and the problem got solved

Do not use FragmentPagerAdapter.
you have to use FragmentStatePagerAdapter on ViewPagerAdapter Class.
class ViewPagerAdapter extends FragmentStatePagerAdapter
{
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 null to display only the icon
return null;
}
}

Passing object to sliding tabs fragment on create

I am trying to pass an object that is retrieved and created during my main activities on create method to one of the fragments of my sliding tabs layout.
Since this object is created over a network connection my plan was to receive the data during the creation of the Main Activity then pass the resulting object to my fragments. However this seems easier said than done. The resulting object will then get passed to a recycler view in the Forecast fragment.
I have read various methods including implementing the parcelable interface on my model object, storing it as a bundle and trying to send it over to the fragment. However it always came up null. I believe this was due to me creating a new fragment in memory and not passing the bundle to the fragment that was displayed. I also don't have any ID's for the fragments so locating them by ID isn't possible, at least to my knowledge.
If anyone could point me in the right direction Id be greatly appreciative.
Main Activity.java
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MAIN ACTIVITY";
#Bind(R.id.toolBar) Toolbar mToolbar;
#Bind(R.id.viewPager) ViewPager mViewPager;
#Bind(R.id.tabLayout) SlidingTabLayout mTabLayout;
private ViewPagerAdapter mAdapter;
private String mForecastsTabName = "Forecasts";
private String mAlertsTabName = "Alerts";
private String mTabTitles[] = {mForecastsTabName, mAlertsTabName};
private int mNumberOfTabs = 2;
private Forecast[] mForecasts;
private JsonParser mJsonParser = new JsonParser();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.bind(this);
setSupportActionBar(mToolbar);
setupSlidingTabs();
}
private void setupSlidingTabs() {
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
mAdapter = new ViewPagerAdapter(getSupportFragmentManager(), mTabTitles, mNumberOfTabs);
// Assigning the ViewPages View and setting the adapter
mViewPager.setAdapter(mAdapter);
// Assigning the Sliding Tab Layout View
mTabLayout.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width
// Setting Custom Color for the Scroll bar indicator of the Tab View
mTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
#Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.ColorAccent);
}
});
mTabLayout.setViewPager(mViewPager);
}
Forecast Fragment.java
public class ForecastFragment extends Fragment {
private static final String FORECAST_KEY = "FORECAST_KEY";
private static final String TAG = "FRAGMENT";
private Forecast[] mForecasts;
#Bind(R.id.recyclerView) RecyclerView mRecyclerView;
#Bind(R.id.emptyView) TextView mEmptyView;
#Bind(R.id.locationButton) Button mLocationButton;
public static ForecastFragment newInstance(Forecast[] forecasts) {
ForecastFragment fragment = new ForecastFragment();
Bundle bundle = new Bundle();
bundle.putParcelableArray(FORECAST_KEY, forecasts);
fragment.setArguments(bundle);
return fragment;
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Initialize dataset, this data would usually come from a local content provider or
// remote server.
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.forecast_tab_fragment, container, false);
ButterKnife.bind(this, view);
displayEmptyViewIfNoData();
ForecastAdapter adapter = new ForecastAdapter(getActivity(), mForecasts);
mRecyclerView.setAdapter(adapter);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(layoutManager);
return view;
}
private void displayEmptyViewIfNoData() {
if (mForecasts == null || mForecasts.length < 1) {
mRecyclerView.setVisibility(View.GONE);
mEmptyView.setVisibility(View.VISIBLE);
mLocationButton.setVisibility(View.VISIBLE);
}
else {
mRecyclerView.setVisibility(View.VISIBLE);
mEmptyView.setVisibility(View.GONE);
mLocationButton.setVisibility(View.GONE);
}
}
#OnClick(R.id.locationButton)
public void selectLocations(View view) {
Intent intent = new Intent(getActivity(), LocationSelectionActivity.class);
intent.putExtra(ActivityConstants.CALLING_ACTIVITY, ActivityConstants.FORECAST_ACTIVITY);
startActivity(intent);
}
}
ViewPagerAdapter.java
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
// This will Store the Titles of the Tabs which are Going to be passed when ViewPagerAdapter is created
String mTitles[];
// Store the number of tabs, this will also be passed when the ViewPagerAdapter is created
int mNumberOfTabs;
SparseArray<Fragment> registeredFragments = new SparseArray<>();
public ViewPagerAdapter(FragmentManager fm, String titles[], int numberOfTabs) {
super(fm);
mTitles = titles;
mNumberOfTabs = numberOfTabs;
}
//This method return the fragment for the every position in the View Pager
#Override
public Fragment getItem(int position) {
if (position == 0) {
ForecastFragment forecastFragment = new ForecastFragment();
return forecastFragment;
}
else if (position == 1) {
AlertFragment alertFragment = new AlertFragment();
return alertFragment;
}
return null;
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
// This method return the titles for the Tabs in the Tab Strip
#Override
public CharSequence getPageTitle(int position) {
return mTitles[position];
}
#Override
public int getCount() {
return mNumberOfTabs;
}
}
Forecast_tab_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/ColorPrimaryLight">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="#dimen/activity_vertical_margin"/>
<TextView
android:id="#+id/emptyView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/empty_forecast_message"
android:textColor="#color/ColorTextPrimary"
android:gravity="center"
android:visibility="gone"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="115dp"/>
<Button
android:id="#+id/locationButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/button_shape"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:textColor="#color/ColorTextPrimary"
android:text="#string/add_forecast_button"
android:visibility="gone"
android:layout_alignParentBottom="false"
android:layout_centerHorizontal="true"
android:layout_below="#+id/emptyView"
android:layout_marginTop="24dp"/>
</RelativeLayout>

When you do this code below, you can hand the data to your fragment.
In your Activity, call below, when the data is ready:
mAdapter.getFragment(index).setData(dataObject);
or
mAdapter.getFragment(mViewPager.getCurrentItem()).setData(dataObject);
Your FragmentPagerAdater should be like this:
class CustomPagerAdapter extends FragmentPagerAdapter {
SparseArray<App4StoreBaseSubFragment> registeredFragments = new SparseArray<App4StoreBaseSubFragment>();
public CustomPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
App4StoreBaseSubFragment fragment = (App4StoreBaseSubFragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public ForecastFragment getFragment(int position){
return registeredFragments.get(position);
}
}
Your Fragment should be like this:
public class ForecastFragment extends Fragment {
public void setData(Forecast forecast){
//write code here to change UI
}
}

Sliding Tabs with RecycleView Fragments and Swipe to Refresh

i'm having some issues implementing a Sliding Tabs activity that contains 2 Fragments and a Swipe Down to Refresh layout, namely implementing the Swipe Down to Refresh part (the rest is working just fine).
First here are my XML files.
The Main Activity XML , which contains the ViewPager wrapped in an SwipeRefreshLayout :
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.popal.soul.MovieListActivityTEST">
<com.example.popal.soul.SlidingTabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="#color/ColorPrimary"/>
<android.support.v4.widget.SwipeRefreshLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/swipeContainer"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:layout_weight="1">
</android.support.v4.view.ViewPager>
</android.support.v4.widget.SwipeRefreshLayout>
And the first tab XML , one of the 2 tabs (both are similar, so i`ll only post one)
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android">
<android.support.v7.widget.RecyclerView
android:id="#+id/cardList"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ProgressBar
android:id="#+id/progress_bar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
</RelativeLayout>
Now, my main activity, which handles the ViewPager, Adapter an the SlidingTabsLayout.
public class MovieListActivityTEST extends AppCompatActivity {
ViewPager pager;
ViewPagerAdapter adapter;
SlidingTabLayout tabs;
CharSequence Titles[]={"Home","Events"};
int Numboftabs =2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_movie_list_activity_test);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true);
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
#Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
}
And finally, my fragment for the first Tab
public class Tab1 extends Fragment {
public MovieListAdapter movieListAdaptor;
public RecyclerView recycleList;
private SwipeRefreshLayout swipeContainer;
private List<MovieListAdapter.MovieDetails> movieList = new ArrayList<MovieListAdapter.MovieDetails>();
private ProgressBar progressBar;
private final static String MOVIES_POST_REQUEST ="//Long String, Edited out since it`s not relevant"
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1, container, false);
recycleList = (RecyclerView) v.findViewById(R.id.cardList);
progressBar = (ProgressBar) v.findViewById(R.id.progress_bar);
progressBar.setVisibility(View.VISIBLE);
swipeContainer = (SwipeRefreshLayout) v.findViewById(R.id.swipeContainer);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recycleList.setLayoutManager(llm);
swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
movieListAdaptor.clear();
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
swipeContainer.setRefreshing(false);
}
});
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
return v;
}
The issue is, i'm getting a NULL Pointer Exception at swipeContainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {...} method, which i guess is because the Swipe-to-Refresh layout is in the main activity XML, and not the tabs fragment. So what is the proper way to implement this ? I also tried implementing a Swipe to refresh layout in one of the Tabs XML instead of wrapping the ViewPager in it, like above, but it would crash when swiping from tab to another.
Here`s the code from the entire fragment in Tab1, for tobs answer below
public class MoviesTabFragment extends Fragment implements Refreshable {
public MovieListAdapter movieListAdaptor;
public RecyclerView recycleList;
//private SwipeRefreshLayout swipeContainer;
public List<MovieListAdapter.MovieDetails> movieList = new ArrayList<MovieListAdapter.MovieDetails>();
public ProgressBar progressBar;
public final static String MOVIES_POST_REQUEST ="";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v =inflater.inflate(R.layout.tab_1, container, false);
recycleList = (RecyclerView) v.findViewById(R.id.cardList);
progressBar = (ProgressBar) v.findViewById(R.id.progress_bar);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recycleList.setLayoutManager(llm);
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
return v;
}
#Override
public void refresh() {
new Send_data_to_server().execute(MOVIES_POST_REQUEST);
}
public class Send_data_to_server extends AsyncTask<String, Void, String> {
private String data_poster;
private String data_fanart;
// protected void onPreExecute() {
// progressBar.setVisibility(View.VISIBLE);
// }
protected String doInBackground(String... params)
{
String jason_data = params[0];
HttpClient http_con = new HttpClient();
String output_from_server = http_con.establish_con(jason_data);
Log.i("DataFromServer", output_from_server);
JSONObject json_Obj = null;
JSONObject child_obj = null; //creating the "result" object in the main JSON Object
try {
json_Obj = new JSONObject(output_from_server);
child_obj = create_subObject("result", json_Obj);
JSONArray jsonArray = child_obj.optJSONArray("movies");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String title_data = jsonObject.optString("label").toString();
String plot_data = jsonObject.optString("plot").toString();
String year_data = jsonObject.optString("year").toString();
String movie_id_data = jsonObject.optString("movieid").toString();
String imdb_score = jsonObject.optString("rating").toString();
String imdb_score_short = imdb_score.substring(0, 3);
JSONObject child_obj2 = create_subObject("art", jsonObject);
data_poster = child_obj2.optString("poster").toString();
data_fanart = child_obj2.optString("fanart").toString();
JSONEncodePosterFanart encodePosterFanart = new JSONEncodePosterFanart();
String jason_dataPoster = encodePosterFanart.GetPosterFanartEncodedURL(data_poster);
String jason_dataFanart = encodePosterFanart.GetPosterFanartEncodedURL(data_fanart);
HttpClient http = new HttpClient();
String output_from_serverPoster = http.establish_con(jason_dataPoster);
HttpClient http2 = new HttpClient();
String output_from_serverFanart = http2.establish_con(jason_dataFanart);
JSONPosterFanart poster_fanart = new JSONPosterFanart();
String post_dl = poster_fanart.GetPosterFanart(output_from_serverPoster);
JSONPosterFanart poster_fanart2 = new JSONPosterFanart();
String fanart_dl = poster_fanart2.GetPosterFanart(output_from_serverFanart);
if (null == movieList) {
movieList = new ArrayList<MovieListAdapter.MovieDetails>();
}
MovieListAdapter.MovieDetails item = new MovieListAdapter.MovieDetails(title_data+" ("+year_data+")", post_dl, fanart_dl,plot_data,movie_id_data,imdb_score_short);
movieList.add(item);
}
} catch (JSONException e) {
e.printStackTrace();
}
return output_from_server;
}
protected void onPostExecute(String output_from_server) {
super.onPostExecute(output_from_server);
//progressBar.setVisibility(View.INVISIBLE);
movieListAdaptor = new MovieListAdapter(getActivity(), movieList);
recycleList.setAdapter(movieListAdaptor);
}
private JSONObject create_subObject(String tagName, JSONObject jObj) throws JSONException {
JSONObject subObj = jObj.getJSONObject(tagName); //getJSONObject returns the value from tagName (in our case jason_Obj that is being passed ar a param)
return subObj;
}
}
}
And the RecycleView adapter:
public class MovieListAdapter extends RecyclerView.Adapter<MovieListAdapter.MovieViewHolder> {
public List<MovieDetails> movieList;
private Context mContext;
public MovieListAdapter(Context mContext, List<MovieDetails> movieList) {
this.mContext = mContext;
this.movieList = movieList;
}
#Override
public int getItemCount() {
return movieList.size();
}
public void clear() {
movieList.clear();
notifyDataSetChanged();
}
#Override
public MovieViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View itemView = LayoutInflater.
from(viewGroup.getContext()).
inflate(R.layout.card_layout_movies_list, viewGroup, false);
return new MovieViewHolder(itemView);
}
#Override
public void onBindViewHolder(MovieViewHolder movieViewHolder, int i) {
MovieDetails mdet = movieList.get(i);
String fanart = "http://192.168.1.128/"+mdet.getImageViewFanart();
String poster = "http://192.168.1.128/"+mdet.getImageViewPoster();
Log.i("fanart", fanart);
Log.i("poster", poster);
movieViewHolder.vTitle.setText(mdet.Title);
Picasso.with(mContext).load(poster)
.resize(500, 746)
.error(R.drawable.poster_placeholder)
.placeholder(R.drawable.poster_placeholder)
.into(movieViewHolder.vPoster);
Picasso.with(mContext).load(fanart)
.resize(960, 540)
.error(R.drawable.fanart_placeholder)
.placeholder(R.drawable.fanart_placeholder)
.into(movieViewHolder.vFanart);
movieViewHolder.vplot = mdet.getPlot();
movieViewHolder.vmovie_id = mdet.getMovie_id();
}
public class MovieViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
protected TextView vTitle;
protected ImageView vPoster;
protected ImageView vFanart;
protected String vplot;
protected String vmovie_id;
protected String vimdb_score;
public MovieViewHolder(View v)
{
super(v);
vplot = new String();
vmovie_id = new String();
vimdb_score = new String();
vTitle = (TextView) v.findViewById(R.id.title);
vPoster = (ImageView) v.findViewById(R.id.imageViewPoster);
vFanart = (ImageView) v.findViewById(R.id.imageViewFanart);
v.setOnClickListener(this);
}
#Override
public void onClick(View v) {
int position = getLayoutPosition();
MovieDetails mov = movieList.get(position);
Intent intent = new Intent(mContext, MovieDetailsPageActivity.class);
Bundle bundle = new Bundle();
bundle.putString("movieid", mov.getMovie_id());
bundle.putString("plot", vplot);
bundle.putString("fanart_path", mov.getImageViewFanart());
bundle.putString("imdb_score", mov.getImdb_score());
intent.putExtras(bundle);
mContext.startActivity(intent);
}
}
public static class MovieDetails {
protected String Title;
protected String imageViewPoster;
protected String imageViewFanart;
protected String plot;
protected String movie_id;
protected String imdb_score;
public MovieDetails(String Title, String imageViewPoster,String imageViewFanart, String plot, String movie_id ,String imdb_score)
{
this.Title = Title;
this.imageViewPoster = imageViewPoster;
this.imageViewFanart = imageViewFanart;
this.plot = plot;
this.movie_id = movie_id;
this.imdb_score = imdb_score;
}
public String getTitle() {return Title;}
public String getImageViewPoster() {
return imageViewPoster;
}
public String getImageViewFanart() {
return imageViewFanart;
}
public String getPlot() {return plot;}
public String getMovie_id() {return movie_id;}
public String getImdb_score() {return imdb_score;}
}
}
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
CharSequence Titles[];
int NumbOfTabs;
public ViewPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
super(fm);
this.Titles = mTitles;
this.NumbOfTabs = mNumbOfTabsumb;
}
#Override
public Fragment getItem(int position) {
if(position == 0)
{
MoviesTabFragment moviesTabFragment = new MoviesTabFragment();
return moviesTabFragment;
}
else
{
TVShowsTabFragment TVShowsTabFragment = new TVShowsTabFragment();
return TVShowsTabFragment;
}
}
#Override
public CharSequence getPageTitle(int position) {
return Titles[position];
}
#Override
public int getCount() {
return NumbOfTabs;
}

You're getting the NullPointerException because you inflate your fragment layout from R.layout.tab_1 which does not contain a SwipeRefreshLayout.
If you want the layout to be the parent of your ViewPager, I would recommend you to move your code which manages the RefreshLayout to the MainActivity:
public class MovieListActivityTEST extends AppCompatActivity {
ViewPager pager;
ViewPagerAdapter adapter;
SwipeRefreshLayout refreshLayout;
SlidingTabLayout tabs;
CharSequence Titles[]={"Home","Events"};
int Numboftabs =2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_movie_list_activity_test);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true);
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
#Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.tabsScrollColor);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
// Assign your refresh layout
refreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipeContainer);
refreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
Refreshable r = (Refreshable) adapter.getItemAt(pager.getCurrentItem());
r.refresh();
}
});
}
where each of your tab fragments implements a Refreshable interface:
public interface Refreshable {
void refresh();
}
and your adapter keeps track on all fragments:
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
// list that keeps references to all attached Fragments
private SparseArray<Fragment> pages = new SparseArray<>();
...
public Fragment getItem(int position) {
Fragment f;
if(position == 0) {
...
} else { ... }
// add fragment to the list
pages.put(position, f);
}
public void destroyItem(ViewGroup container, int position, Object object) {
// remove fragment from list if it existed
if(pages.indexOfKey(position) >= 0) {
pages.remove(position);
}
super.destroyItem(container, position, object);
}
// return the attached Fragment that is associated with the given position
public Fragment getItemAt(int position) {
return pages.get(position);
}
}