Develop Reference

Impossible to add or remove pages dinamically from ViewPager Android Activity

I've read all stackOverflow answers regarding this topic, and any of them worked for me, or I couldn't make it myself.
As you can see in the code below, I added the default ViewPager Activity from Android Studio, and now I need to add new pages or remove existing pages from the corresponding buttons.
So, the activity is loading correctly and gets the correct number of pages, and I can also change the information in each of them successfully. As you can see, the app is connected to Firebase and I get from there the total number of pages (dogs) that my activity should have, this is working well.
Now, How can I add a new page, move to that page, and update the adapter and total number of pages?
Same for removing, How can I remove the current page, then move to another one and update the adapter with no problems?
I'm getting totally crazy with this, spent the whole day with diffeent solutions I found in stackoverflow, but could not make it. I'm now confused about when to use the "notifyDataSetChanged()", if it is a good idea override the "getItemPosition" or not, etc.
I would appreciate if someone could finally help me adapting the answer to my project, it's the default ViewPager just modified small parts to try to fix it, but don't know what else I can do.
Thank you in advance and sorry for my english.
Note: Some functions like "updateIntValueFromCurrentUser()" are declared in MainActivity but working, they are related to firebase queries etc so I'm not focusing on this.
public class DummyViewPagerActivity extends MainActivity {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
private static ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dummy_view_pager);
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.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
//Creating menu bar
#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_dummy_view_pager, menu);
return true;
}
//Creating the two buttons to save and delete the images
#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.
switch (item.getItemId()) {
case R.id.add:
updateIntValueFromCurrentUser("dogs_number", person.getDogs_number()+1);
return true;
case R.id.edit:
return true;
case R.id.delete:
updateIntValueFromCurrentUser("dogs_number", person.getDogs_number()-1);
return true;
default:
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) {
View rootView = null;
try {
rootView = inflater.inflate(R.layout.fragment_dummy_view_pager, container, false);
TextView dogName = (TextView) rootView.findViewById(R.id.dog_name);
dogName.setText(allDogs.get((getArguments().getInt(ARG_SECTION_NUMBER)) - 1).getName());
} catch (Exception e) {
Log.e("RaisedException()", e.getMessage());
}
return rootView;
}
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentStatePagerAdapter {
public 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 getItemPosition(Object object) {
// POSITION_NONE makes it possible to reload the PagerAdapter
return POSITION_NONE;
}
#Override
public int getCount() {
// Show x total pages.
return person.getDogs_number();
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}

Adding/Removing items from FragmentViewPager is a bit tricky thing to do:
Try using this adapter and let me know is it working for you.
public class CodebaseFragmentPagerAdapter extends FragmentStatePagerAdapter {
private List<Fragment> mFragmentList = new ArrayList<Fragment>();
public CodebaseFragmentPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
public void removeItem(int position){
mFragmentList.remove(position == 0 ? 0 : position - 1);
this.notifyDataSetChanged();
}
public void clearAllItems(){
mFragmentList.clear();
this.notifyDataSetChanged();
}
public void updateItem(int position, Fragment fragment){
mFragmentList.set(position, fragment);
notifyDataSetChanged();
}
#Override
public int getItemPosition(Object object) {
if (mFragmentList.contains(object)) return mFragmentList.indexOf(object);
else return POSITION_NONE;
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment) {
mFragmentList.add(fragment);
notifyDataSetChanged();
}
}

Implementing Tabs in Android

I like to check I am doing the right thing or is there a better way than this.
I like to implement tabs in Android application. I found out that I should use Fragment.
Then I implemented my application with TabbedActivity.Inside I added in Tabs.
I have added Tab in the onCreate() of the MainActivity as
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("Accelerometer"));
tabLayout.addTab(tabLayout.newTab().setText("Gyroscope"));
// 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.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
mViewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
Since I want to use two xmls for two different fragments (frangment1.xml and frangment2.xml), I created two blank fragments and inside PlaceholderFragment class's, I added frangment1.xml and frangment2.xml using cnt variable
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";
private static int cnt = 0;
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) {
View rootView = null;
if(cnt== 0) {
rootView = inflater.inflate(R.layout.tab_fragment1, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.frag1);
cnt++;
}else if(cnt== 1){
rootView = inflater.inflate(R.layout.tab_fragment2, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.frag2);
}
//textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
I like to check is that the correct way or any other better way for that.

Hey there is not much to say about this code. I have not tried to run your code. But if it run for you its fine. Even I use to do this type of Tabs implementation in android. But since there are many changes from then as per the new android design library. There are tons of new features, not just in designs but also in functionalities. You might wanna check this link for some of them being implemented here.
http://www.androidhive.info/2015/09/android-material-design-working-with-tabs/
Also for guidelines from google on tabs, their implementations, specifications and all that stuff check this out.
https://www.google.com/design/spec/components/tabs.html#tabs-usage

No this is not right.
You shouldn't make the two fragments inside one fragment. You should separate them to step out of the if condition in every method (checking which view is inflated). Suppose now you have two separate fragments, you just need to check the position in your adapter to choose which fragment you need in which position.
#Override
public Fragment getItem(int position) {
switch(position) {
case 0:
return new MyFragment1();
break;
case 1:
return new MyFragment2();
break;
}
return null;
}

How to access Fragment's child views inside fragment's parent Activity?

I have a supported fragment activity which will load diff fragments. The fragment has some textView with id = "score" and I want to get its handle but findViewById for score's textView returns null. Why so?
textView is placed in fragment
public class MyActivity extends extends ActionBarActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks{
private TextView scoreBoardTextView = null;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
scoreBoardTextView = (TextView) findViewById(R.id.score); //this returns null
}
#Override
public void onNavigationDrawerItemSelected(int position) {
//set fragment
}
}

Note:
Directly accessing fragment's views outside fragment is not a good idea. You should use fragment callback interfaces to handle such cases and avoid bugs. The following way works but it is not recommended as it is not a good practice.
If you want to access the TextView of Fragment inside its parent Activity then you should define a method inside your Fragment class like this:
public class MyFragment extends Fragment {
TextView mTextView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_main, container, false);
mTextView = (TextView) view.findViewById(R.id.textView1);
return view;
}
public void setTextViewText(String value){
mTextView.setText(value);
}
}
Now you can use this inside your Activity like this:
myFragment.setTextViewText("foo");
here myFragment is of type MyFragment.
If you want to access the whole TextView then you can define a method like this inside MyFragment.java:
public TextView getTextView1(){
return mTextView;
}
By this you can access the TextView itself.
Hope this Helps. :)

It is possible with following way:
Keep reference of inflated view in the Fragment like this :
public class MyFragment extends SherlockFragment{
MainMenuActivity activity;
public View view;
public MyFragment(){
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if ( getActivity() instanceof MainMenuActivity){
activity = (MainMenuActivity) getActivity();
}
view = inflater.inflate(R.layout.aboutus, container, false);
return view;
}
}
Create a function in the Activity, like this:
public class MainMenuActivity extends SherlockFragmentActivity {
SherlockFragment fragment = null;
public void switchContent(SherlockFragment fragment) {
this.fragment = fragment;
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.mainmenu, fragment)
.commit();
invalidateOptionsMenu();
}
Its purpose is to keep reference of current fragment. Whenever you wanna switch fragment, you call above function, like this (from fragment):
activity.switchContent( new MyFragment_2());
Now you've current fragment reference. So you can directly access Fragment's views in Activity like this: this.fragment.view

You have no need of reference of Fragment view to get its components in Activity. As you can directly access layout components of a Fragment in parent Activity.
Simply you can access any component by this
findViewById(R.id.child_of_fragment_layout);

In order to access the TextView or Button or whatever in your fragment you need to do the following:
public class BlankFragment extends Fragment {
public View view;
public TextView textView;
public Button button;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
view =inflater.inflate(R.layout.fragment_blank, container, false);
textView = (TextView)view.getRootView().findViewById(R.id.textView_fragment1);
return view;
}
public void changeTextOfFragment(String text){
textView.setText(text);
view.setBackgroundResource(R.color.colorPrimaryDark);
}
Once that is done in your MainActivity or any other where you want to access your TextView from your Fragment you should make sure to set up the fragment in your OnCreate() method other ways it will most likely throw nullPointer. So your activity where you want to change the TextView should look smth like this:
public class MainActivity extends AppCompatActivity {
private Button button1;
private FragmentManager fragmentManager;
private FragmentTransaction fragmentTransaction;
BlankFragment blankFragment = new BlankFragment();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1 = (Button)findViewById(R.id.button1);
changeFragment();
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment1,blankFragment);
fragmentTransaction.commit();
}
private void changeFragment(){
button1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
blankFragment.changeTextOfFragment("Enter here the text which you want to be displayed on your Updated Fragment");
}
});
}
Hope this helps :)

You can access with getView method of Fragment class.
For example You have a TextView in Your MyFragment with id of "text_view" In Your Activity make a Fragment of Yours:
MyFragment myFragment = new MyFragment();
And when You need a child just call getView and then find Your childView.
View view = myFragment.getView();
if (view !=null) {
view.findViewById(R.id.text_view).setText("Child Accessed :D");
}
Note: if you want the root view of your fragment, then myFragment.getView(); is simply enough.

Just put in fragment instead of putting in activity:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_new_work_order,
container, false);
TextView scoreBoardTextView = (TextView) rootView.findViewById(R.id.score);
return rootView;
}

Only doing this:
((Your_Activity) this.getActivity()).YouyActivityElements;

If your TextView placed inside Fragment that case you cannot access TextView inside your Fragment Parent Activity you can set the interface for intercommunication between Fragment and Activity and send Data when you click on TextView or anyother thing which you want to happend

You can't access Fragment element in Parent Activity, But You can pass values to your Fragment by following way.
in your onNavigationDrawerItemSelected method of MyActivity do the following
int myScore = 100;
#Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager
.beginTransaction()
.replace(R.id.container,
MyFragment.newInstance(myScore)).commit();
}
And in MyFragment class create a method called newInstance like following
private static final String SCORE = "score";
public static MyFragment newInstance(int score) {
MyFragment fragment = new MyFragment();
Bundle args = new Bundle();
args.putInt(SCORE, score);
fragment.setArguments(args);
return fragment;
}
And in MyFragment's onCreateView() method
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
TextView textView = (TextView) rootView
.findViewById(R.id.score);
textView.setText(Integer.toString(getArguments().getInt(
SCORE)));
return rootView;
}
That's All, I hope this will help you. If not please let me know.

The score textView is in the layout of fragment, it's not in the layout of the MyActivity, i.e. R.layout.activity_home. So you could find the score textview in that fragment once you inflate the corresponding layout file.

It returns null cause the TextView is an element of the Fragment, not the Activity.
Please note that the idea of using Fragment is to encapsulate a module inside the Fragment, which means the Activity should not have direct access to it's properties. Consider moving your logic where you get the TextView reference inside the Fragment

Simply declare TextView as public in fragment, initialize it by findViewById() in fragment's onCreateView(). Now by using the Fragment Object which you added in activity you can access TextView.

You need to call method findViewById from your fragment view.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
scoreBoardTextView = (TextView) mNavigationDrawerFragment.getView().findViewById(R.id.score);
}
This way works for me.

I suggest you to make the textview part of your activity layout. Alternately you can have the textview as a separete fragment. Have a look at my question here. Its similar to yours but in reverse direction. Here's a stripped down version of code I used in my project. The explanation are along the code.
The Activity Class
public class MainActivity extends ActionBarActivity {
PlaceFragment fragment;
TextView fragmentsTextView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
Bundle bundle = new Bundle();
bundle.putString("score", "1000");
fragment = PlaceFragment.newInstance(bundle);
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.container, fragment);
ft.addToBackStack(null);
ft.commit();
// method 1
// fragment is added some ways to access views
// get the reference of fragment's textview
if (fragment.getTextView() != null) {
fragmentsTextView = fragment.getTextView();
}
// method 2
// using static method dont use in production code
// PlaceFragment.textViewInFragment.setText("2000");
// method 3
// let the fragment handle update its own text this is the recommended
// way wait until fragment transaction is complete before calling
//fragment.updateText("2000");
}
}
The fragment class:
public class PlaceFragment extends Fragment {
public TextView textViewInFragment;// to access via object.field same to
// string.length
// public static TextView textViewInFragment;//to access via
// PlaceFragment.textView dont try this in production code
public PlaceFragment() {
}
public static PlaceFragment newInstance(Bundle bundle) {
PlaceFragment fragment = new PlaceFragment();
fragment.setArguments(bundle);
return fragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View view = inflater.inflate(R.layout.fragment_place, container, false);
textViewInFragment = (TextView) view
.findViewById(R.id.textViewInFragment);
return view;
}
#Override
public void onStart() {
// TODO Auto-generated method stub
super.onStart();
if (getArguments() != null) {
textViewInFragment.setText(getArguments().getString("score"));
}
}
public TextView getTextView() {
if (textViewInFragment != null) {
return textViewInFragment;// returns instance of inflated textview
}
return null;// return null and check null
}
public void updateText(String text) {
textViewInFragment.setText(text);// this is recommended way to alter
// view property of fragment in
// activity
}
}
Communication from activity to fragment is straight forward. This is because activity contains fragment. Keep the fragment object and access its property via setters and getters or the public fields inside it. But communication from fragment to activity requires an interface.

why you don't access it directly from your FragmentPagerAdapter,
SubAccountFragment subAccountFragment = (SubAccountFragment) mSectionsPagerAdapter.getItem(1);
subAccountFragment.requestConnectPressed(view);
and here is the full example:
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Locale;
public class TabsActivity extends ActionBarActivity implements ActionBar.TabListener {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tabs);
// Set up the action bar.
final ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// 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.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
ActionBar.Tab tab = actionBar.newTab();
View tabView = this.getLayoutInflater().inflate(R.layout.activity_tab, null);
ImageView icon = (ImageView) tabView.findViewById(R.id.tab_icon);
icon.setImageDrawable(getResources().getDrawable(mSectionsPagerAdapter.getPageIcon(i)));
TextView title = (TextView) tabView.findViewById(R.id.tab_title);
title.setText(mSectionsPagerAdapter.getPageTitle(i));
tab.setCustomView(tabView);
tab.setTabListener(this);
actionBar.addTab(tab);
}
}
#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_tabs, 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_logout) {
finish();
gotoLogin();
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public ProfileFragment profileFragment;
public SubAccountFragment subAccountFragment;
public ChatFragment chatFragment;
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
profileFragment = new ProfileFragment();
subAccountFragment = new SubAccountFragment();
chatFragment = new ChatFragment();
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return profileFragment;
case 1:
return subAccountFragment;
case 2:
return chatFragment;
}
return null;
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
public int getPageIcon(int position) {
switch (position) {
case 0:
return R.drawable.tab_icon_0;
case 1:
return R.drawable.tab_icon_1;
case 2:
return R.drawable.tab_icon_2;
}
return 0;
}
}
public void gotoLogin() {
Intent intent = new Intent(this, LoginActivity.class);
this.startActivity(intent);
}
public void requestConnectPressed(View view){
SubAccountFragment subAccountFragment = (SubAccountFragment) mSectionsPagerAdapter.getItem(1);
subAccountFragment.requestConnectPressed(view);
}
}

If the view is already inflated (e.g. visible) on the screen then you can just use findViewById(R.id.yourTextView) within the activity as normal and it will return the handle to the text view or null if the view was not found.

I just use methods to access fragment views from parent activity, because we create a new fragment class object to insert the fragment. So I do like this.
class BrowserFragment : Fragment(), Serializable {
private lateinit var webView: NestedScrollWebView
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
webView = view.findViewById(R.id.web_view)
}
fun getWebView(): WebView {
return webView
}
}
In MainActivity
val browserFragment = BrowserFragment()
val fragmentTransaction = supportFragmentManager.beginTransaction()
fragmentTransaction.add(R.id.browser_fragment_placeholder, browserFragment)
fragmentTransaction.commit()
val webView = browserFragment.getWebView()

Change Fragment with ViewPager

I am using PagerSlidingTab Library for ViewPager. And I want to change Fragment while scrolling of tabs. It is working fine. Check out my code.
I am using AsynTask() on each Fragment.
When the App opens with the MainActivity, First Fragment is attached to the activity, But It shows two AsynTask() dialog message, one from First and another from Second Fragment. And When I scroll to second tab, It shows dialog message of Third Fragment.
So, If I scroll from left to right in tabs, the Fragment right to the current fragment is displayed and if i scroll from right to left, the Fragment left to the current Fragment is displayed.
Please help me to solve the problem.
My Code:
public class PageSlidingTabStripFragment extends Fragment {
public static final String TAG = PageSlidingTabStripFragment.class
.getSimpleName();
public static PageSlidingTabStripFragment newInstance() {
return new PageSlidingTabStripFragment();
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.pager, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
PagerSlidingTabStrip tabs = (PagerSlidingTabStrip) view
.findViewById(R.id.tabs);
ViewPager pager = (ViewPager) view.findViewById(R.id.pager);
MyPagerAdapter adapter = new MyPagerAdapter(getChildFragmentManager());
pager.setAdapter(adapter);
tabs.setViewPager(pager);
}
public class MyPagerAdapter extends FragmentPagerAdapter {
public MyPagerAdapter(android.support.v4.app.FragmentManager fm) {
super(fm);
}
private final String[] TITLES = { "Instant Opportunity", "Events",
"Experts" };
#Override
public CharSequence getPageTitle(int position) {
return TITLES[position];
}
#Override
public int getCount() {
return TITLES.length;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new InstantOpportunity();
case 1:
return new Events();
case 2:
return new Experts();
default:
break;
}
return null;
}
}
}

Explanation:
It turns out there is an easier implementation for scrollable tabs which doesn't involve another library. You can easily implement tabs into your app using normal Android code straight from the default SDK.
The Code
Main Class:
public class PageSlidingTabStripFragment extends Fragment {
//Variables
private ViewPager viewPager;
private PagerTitleStrip pagerTitleStrip;
public PageSlidingTabStripFragment() {
// Required empty public constructor
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//Find your pager declared in XML
viewPager = (ViewPager) getView().findViewById(R.id.pager);
//Set the viewPager to a new adapter (see below)
viewPager.setAdapter(new MyAdapter(getFragmentManager()));
//If your doing scrollable tabs as opposed to fix tabs,
//you need to find a pagerTitleStrip that is declared in XML
//just like the pager
pagerTitleStrip = (PagerTitleStrip)
getView().findViewById(R.id.pager_title_strip);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.[your layout name here], container, false);
}
}
Adapter:
//Note: this can go below all of the previous code. Just make sure it's
//below the last curly bracket in your file!
class MyAdapter extends FragmentStatePagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int arg0) {
Fragment fragment = null;
if (arg0 == 0) {
fragment = new InstantOpportunity();
}
if (arg0 == 1) {
fragment = new Events();
}
if (arg0 == 2) {
fragment = new Experts();
}
return fragment;
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
if (position == 0) {
return "Instant Opportunity";
}
if (position == 1) {
return "Events";
}
if (position == 2) {
return "Experts";
}
return null;
}
}
Conclusion:
I hope this helps you understand another way to make scrollable tabs! I have examples on my Github Page about how to make each type (That being Fixed or Scrollable).
Links:
Fixed Tabs Example - Click Here
Scrollable Tabs Example - Click Here
Hope this helps!
Edit:
When asked what to import, make sure you select the V4 support fragments.

please use this example..its very easy.i already implement that.
reference link
hope its useful to you.its best example of pager-sliding-tabstrip.
Use
framelayout compulsory:
FrameLayout fl = new FrameLayout(getActivity());
fl.addView(urFragementView);
and then set your fragement view in this framelayout.

Refresh Fragment Views based on Button Click

I have 2 fragments (tabs) that share some data. When one changes the data, I'd like to have that reflected on the other tab. I researched this on stackOverflow and I think the relevant answer has to do with a .notifyDataSetChanged() call, but I can't make it work. Here's the relevant code...
public class EnterCourseData extends FragmentActivity implements ActionBar.TabListener {
private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
// Tab titles
private String[] tabs = { "Pars", "Handicaps" };
private int courseNumber, teeNumber;
private Tee tee;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_enter_tees);
// Initilization
Intent mIntent = getIntent();
courseNumber = mIntent.getIntExtra("courseNumber",0);
Course course = Global.getCourse(courseNumber);
teeNumber = mIntent.getIntExtra("teeNumber",0);
tee = course.getTee(teeNumber);
viewPager = (ViewPager) findViewById(R.id.pager);
actionBar = getActionBar();
mAdapter = new TabsPagerAdapter(getSupportFragmentManager(), courseNumber, teeNumber);
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Adding Tabs
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name)
.setTabListener(this));
}
/**
* on swiping the viewpager make respective tab selected
* */
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
// on changing the page
// make respected tab selected
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
});
}
and further down, here is the onClick method that necessitates the refresh...
public void savePars(View view){
tee.setSlope(Integer.parseInt(((EditText) findViewById(R.id.enter_tee_slope)).getText().toString()));
tee.setRating(Double.parseDouble(((EditText) findViewById(R.id.enter_tee_rating)).getText().toString()));
mAdapter.notifyDataSetChanged();
}
Here is the TabsPagerAdapter...
public class TabsPagerAdapter extends FragmentPagerAdapter {
int courseNumber, teeNumber;
public TabsPagerAdapter(FragmentManager fm, int courseNumber, int teeNumber) {
super(fm);
this.courseNumber = courseNumber;
this.teeNumber = teeNumber;
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
// Par Entry activity
Fragment parFragment = new ParFragment();
Bundle args = new Bundle();
args.putInt(ParFragment.ARG_COURSE_NUMBER, courseNumber);
args.putInt(ParFragment.ARG_TEE_NUMBER, teeNumber);
parFragment.setArguments(args);
return parFragment;
case 1:
// Handicap Entry fragment activity
Fragment hcpFragment = new HandicapFragment();
args = new Bundle();
args.putInt(HandicapFragment.ARG_COURSE_NUMBER, courseNumber);
args.putInt(HandicapFragment.ARG_TEE_NUMBER, teeNumber);
hcpFragment.setArguments(args);
return hcpFragment;
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 2;
}
}
Here is one Fragment...
public class ParFragment extends Fragment {
public static final String ARG_COURSE_NUMBER = "courseNumber", ARG_TEE_NUMBER = "teeNumber";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_par, container, false);
Bundle args = getArguments();
Course course = Global.getCourse(args.getInt(ARG_COURSE_NUMBER));
((TextView) rootView.findViewById(R.id.display_course_name)).setText(course.getName());
Tee tee = course.getTee(args.getInt(ARG_TEE_NUMBER));
((TextView) rootView.findViewById(R.id.display_tee_name)).setText(tee.getTeeName());
((TextView) rootView.findViewById(R.id.enter_tee_slope)).setText(Integer.toString(tee.getSlope()));
((TextView) rootView.findViewById(R.id.enter_tee_rating)).setText(Double.toString(tee.getRating()));
return rootView;
}
}
And here is the other...
public class HandicapFragment extends Fragment {
public static final String ARG_COURSE_NUMBER = "courseNumber", ARG_TEE_NUMBER = "teeNumber";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_handicap, container, false);
Bundle args = getArguments();
Course course = Global.getCourse(args.getInt(ARG_COURSE_NUMBER));
((TextView) rootView.findViewById(R.id.display_course_name)).setText(course.getName());
Tee tee = course.getTee(args.getInt(ARG_TEE_NUMBER));
((TextView) rootView.findViewById(R.id.display_tee_name)).setText(tee.getTeeName());
((TextView) rootView.findViewById(R.id.enter_tee_slope)).setText(Integer.toString(tee.getSlope()));
((TextView) rootView.findViewById(R.id.enter_tee_rating)).setText(Double.toString(tee.getRating()));
return rootView;
}
}
When the button is clicked, I want to save the values and I want these values to show up on the other fragment.
Help a noob out.
Thanks

You need to communicate between fragments, but a fragment cannot directly communicate with other fragment, all the communication should be done through the activity which holds these fragments.
The steps to follow are :
Define an Interface in the fragment where you have implemented the onClickListener (let it be Fragment A)
Implement the Interface in the activity which holds these fragments
In the method overridden, retrieve the fragment instance from the viewpager adapter and deliver a message to Fragment B by calling it's public methods.
refer this answer to retrieve fragment instance from adapter
For more details about Communicating with Other Fragments, refer here

So there is a trick: just let the fragments have the object reference of one another and call the other's function to load data when you handle the onClickListener of the button.
E.g:
protected void onClickListener(View view) {
if (view == myButton) {
// Do other stuffs here
fragment1.reloadData();
}
}
P/S : I re-post this as answer to have the code formatter.