如何在不承载该片段的活动中刷新从 Listview 接收数据的片段中的 Textview

Question

I have created a bottomNavigation bar which consists of 5 Fragments, so once each tab is clicked it will switch from one fragment to another.

The question is:The second fragment (Search fragment) have 1 TextView with setOnClickListener so once it is been licked a layout activity will open on the top which includes a ListView to allow the user to select/click on a specific Item, so later on this selected item info should be displayed on that TextView within the(Search fragment).

The issue is that this Textview won't be updated, unless I call the mainActivity to so all fragments in bottom Navigation bar will be updated

My question is how I can refresh that specific fragment without calling the MainActivity.

 public class MainActivity extends AppCompatActivity {



final Fragment f1 = new HomeFragment();
final Fragment f2 = new SearchFragment();
final Fragment f3 = new CameraFragment();
final Fragment f4 = new ChatFragment();
final Fragment f6 = new LogginFragment();

final FragmentManager fm = getSupportFragmentManager();
Fragment active = f1;

@Override
 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);



    BottomNavigationViewEx bnve = (BottomNavigationViewEx) findViewById(R.id.bottom_navigation);

    bnve.enableAnimation(false);
    bnve.enableShiftingMode(false);
    bnve.enableItemShiftingMode(false);
    bnve.setOnNavigationItemSelectedListener(navListener);

    if(SharePrefManager.getInstance(this).isLoggedin()){
        finish();
        startActivity(new Intent(this, SuccessActivity.class));
        return;
    }
    fm.beginTransaction().add(R.id.fragment_container, f6, "6").hide(f6).commit();
    //fm.beginTransaction().add(R.id.fragment_container, f5, "5").hide(f5).commit();
    fm.beginTransaction().add(R.id.fragment_container, f4, "4").hide(f4).commit();
    fm.beginTransaction().add(R.id.fragment_container, f3, "3").hide(f3).commit();
    fm.beginTransaction().add(R.id.fragment_container, f2, "2").hide(f2).commit();
    fm.beginTransaction().add(R.id.fragment_container, f1, "1").commit();



}



public BottomNavigationViewEx.OnNavigationItemSelectedListener navListener =
        new BottomNavigationViewEx.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                switch (item.getItemId()) {

                    case R.id.nav_home:
                        fm.beginTransaction().hide(active).show(f1).commit();
                        active = f1;
                        return true;

                    case R.id.nav_search:
                        fm.beginTransaction().hide(active).show(f2).commit();
                        active = f2;
                        return true;
                    case R.id.nav_camera:
                        fm.beginTransaction().hide(active).show(f3).commit();
                        active = f3;
                        return true;
                    case R.id.nav_chat:
                        fm.beginTransaction().hide(active).show(f4).commit();
                        active = f4;
                        return true;
                    case R.id.nav_account:
                        fm.beginTransaction().hide(active).show(f6).commit();
                        active = f6;
                        return true;

                }



                return false;

            }
        };

    }

------------------------SearchFragment Class----------------------------------

This is the search fragment which has the textView (Categories) which supposed to be updated/be refershed without calling the MainActivity

public class SearchFragment extends Fragment  {


 private Context mContext;
 TextView Categories;


static boolean status = false;
String SelectedItem;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    View v = inflater.inflate(R.layout.fragment_search,container,false);
    Categories = (TextView) v.findViewById(R.id.categories);
    SelectedItem = DataHolder.getInstance().getItem();





        Categories.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(mContext, AllCateActivity.class));

            }
        });

        if(status){Categories.setText(SelectedItem);}


    return v;
}

public void ChangeStatus(Boolean status){

    this.status = status;
    }

@Override
  public void onAttach(Context context) {
    super.onAttach(context);
    mContext=context;
     }




 }

--------------------------DataHolder Class---------------------------------

This works as a design pattern to share arguments between the search fragment and Categories_Activity

  public class DataHolder {

 private static DataHolder dataHolder = null;

 private DataHolder() {
     }

  public static DataHolder getInstance() {
if (dataHolder == null)
{
    dataHolder = new DataHolder();
}
return dataHolder;
 }


  private  String item;

 public String getItem() {
return item;
 }

public void setItem(String item) {
 this.item = item;
     }

 }

--------------------------Categories_Activity---------------------------------

This Activity once it's being called a listview will show allowing user to select an item. So once an Item has been selected it will start the MainActivity in order to refresh the Text field in the search Fragment

 public class Categories_Activity extends AppCompatActivity implements View.OnClickListener {

ImageView BacktoMainCate;
ListView subCate;
public String selectedItem;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.tab_subcategory);
    subCate = (ListView)findViewById(R.id.listview_subcate);
    BacktoMainCate = (ImageView)findViewById(R.id.BacktoMainCate);
    BacktoMainCate.setOnClickListener(this);

           final SearchFragment SF = new SearchFragment();
    subCate.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
             selectedItem = String.valueOf(parent.getItemAtPosition(position));
            DataHolder.getInstance().setItem(selectedItem);
            SF.ChangeStatus(true);

  Intent in = new Intent(Categories_Activity.this,SuccessActivity.class);
                startActivity(in);

    });

}





@Override
public void onClick(View v) {

    if (v == BacktoMainCate){
        //startActivity(new Intent(this,AllCateActivity.class));
        finish();
    }




   }
}

Answer 1

I have used SharedPreferences on both Fragment/Activity life cycle.

So once the Categories_Activity get started, Main Activity will go in onPause and with it all its Fragments will be put in onPause. When user clicks on one of the ListView items in the Categories_Activity, data of that selected item will be store inside SharedPreferences like:

PreferenceManager.getDefaultSharedPreferences(Categories_Activity .this)
        .edit().putString(key, selectedItemInfo).apply();

Then override onResume() method inside MainActivity and SearchFragment:

@Override
public void onResume() {
super.onResume();
String value = PreferenceManager.getDefaultSharedPreferences(getContext())
        .getString(key, "");
if (value != null && !value.isEmpty()) {
    Categories.setText(value);
  PreferenceManager.getDefaultSharedPreferences(getContext()).edit().remove(key);
   }
}