Develop Reference

Clear data of fragments in ViewPager with each swipe

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

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

How to create a multi-step registration form using viewpager and multiple fragments?

I want to create a multi-step registration form in my android app. I wish to use the viewpager with multiple fragments and each fragment being a step in a registration.
At the end, I want to submit all the data submitted in each fragment using an activity to a mysql database. Can I get a small sample code for this?
This is what I have tried so far. I am able to implement a viewpager with multiple fragments. I have created an interface in the StepOne.java Fragment so as to communicate to an activity. But I am not able to retrieve data from these fragments. It throws a null-pointer exception on line 52.
Here is my code:
SliderActivity.java:
public class SliderActivity extends AppCompatActivity {
ViewPager viewPager;
EditText edName,edPassword, edConfPass;
TextView tvShowAll;
ViewPagerAdapter mPagerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_slider);
viewPager = findViewById(R.id.view_pager);
mPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(mPagerAdapter);
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
}
public void selectIndex(int newIndex) {
viewPager.setCurrentItem(newIndex);
}
#Override
public void onBackPressed() {
int currentPosition = viewPager.getCurrentItem();
if (currentPosition != 0) {
viewPager.setCurrentItem(viewPager.getCurrentItem()-1);
} else {
super.onBackPressed();
}
}
public class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position)
{
case 0:
return new StepOne();
case 1:
return new StepTwo();
case 2:
return new StepThree();
}
return null;
}
#Override
public int getCount() {
return 3; //three fragments
}
}
}
StepOne.java:
public class StepOne extends Fragment {
Button buttonInFragment1;
EditText edName;
public interface ActivityFragmentCallback {
void onSetName(String name);
}
ActivityFragmentCallback listener;
public StepOne() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View rootView = inflater.inflate(R.layout.fragment_step_one, container, false);
edName = rootView.findViewById(R.id.edName);
buttonInFragment1 = rootView.findViewById(R.id.button_one);
if(buttonInFragment1 != null) {
buttonInFragment1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getContext(),edName.getText().toString(),Toast.LENGTH_SHORT).show();
if(edName != null) {
listener.onSetName(edName.getText().toString());
}
switch (view.getId()){
case R.id.button_one:
((SliderActivity)getActivity()).selectIndex(1);
break;
}
}
});
}
return rootView;
}
#Override
public void onAttach(Context context){
super.onAttach(context);
try {
listener = (ActivityFragmentCallback)context;
}catch (ClassCastException c){
c.printStackTrace();
}
}
}
MessageActivity.java: Here is where I need all the data submitted from all the fragments
public class MessageActivity extends AppCompatActivity implements StepOne.ActivityFragmentCallback {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_message);
}
#Override
public void onSetName(String name){
// tvShowAll = findViewById(R.id.tvShowAll);
// tvShowAll.setText(name);
Toast.makeText(getApplicationContext(),name, Toast.LENGTH_LONG).show();
}
}

Below is some reference link for step by step registration;
Hope you have help
https://github.com/stepstone-tech/android-material-stepper
https://github.com/baoyachi/StepView?utm_source=android-arsenal.com&utm_medium=referral&utm_campaign=3774

Call a method when sliding from one fragment to another

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

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

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

Using viewpager with radiogroup to switch between fragments

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

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

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

Is it possible to know which image display in ViewPager?

I have two images. I used ViewPager to display them individually. I want to know which ones is displaying in the screen. Could you help me to solve it? For example, when I scroll the screen, the first image will display and Toast a message such as "This is first image", do same thing for second image. Thanks in advance. This is my code
public class ViewPagerExample extends FragmentActivity{
private MyAdapter mAdapter;
private ViewPager mPager;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mAdapter = new MyAdapter(getSupportFragmentManager());
mPager = (ViewPager) findViewById(R.id.pager);
mPager.setAdapter(mAdapter);
}
public static class MyAdapter extends FragmentPagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getCount() {
return 2;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
{
return new ImageFragment(R.drawable.image1);
}
case 1:
{
return new ImageFragment(R.drawable.image2);
}
default:
return null;
}
}
}
}
and the ImageFragment class
public class ImageFragment extends Fragment {
private final int imageResourceId;
public ImageFragment(int imageResourceId) {
this.imageResourceId = imageResourceId;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e("Test", "hello");
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.image_layout, container, false);
ImageView imageView = (ImageView) view.findViewById(R.id.imageView1);
imageView.setImageResource(imageResourceId);
return view;
}
}

try something like this
mPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int pager_position) {
// show toast here for images
}
#Override
public void onPageScrollStateChanged(int state) {
}
});

You can use these lines of code to detect the image on swipe
ViewPager.SimpleOnPageChangeListener pageChangeListener = new ViewPager.SimpleOnPageChangeListener(){
#Override
public void onPageSelected(int position) {
super.onPageSelected(position);
System.out.println("Positoin is the=="+position);
if(position==0)
{
///on the zero position you can get the image
}
else
{
///on the first position you can get the image
}
}
};

There is a method yourViewpagerObject.getCurrentItem() which returns the position of currently Viewed page of view pager