Clear data of fragments in ViewPager with each swipe

Question

@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;
}}

Hi. I prepare test fragment. I didnt code whole thing.I am still trying to figure out.Thanks — yardımcı Etis, Jul 28 '20 at 15:57

Ankit Gupta · Accepted Answer · 2020-07-28T23:37:00.147

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
    }

}

If there was a reset view method( reset to default xml) in fragment, this would be so simple. but your second aprroach seems good terms in clear code.thank you — yardımcı Etis, Jul 29 '20 at 12:17

Clear data of fragments in ViewPager with each swipe

1 Answers1