How to use Shared Preference from a Button in another activity? - fragment

Question

Im trying to implement SharedPreferences but, since this is all so new to me, Im confused on how to actually do this. I have an activity that contains Two EditTexts and a Button; those EditTtexts are subject and grade, and the button sends it to a fragment activity, which contains a Recyclerview with its cardview etc. I have no trouble getting the input and displaying it in the Recyclerview list. When I try applying the Shared Preferences to save the custom data from the recyclerview, I have no idea where I should input the code.
I tried several tutorials, and I used gson to set a saveData, but I havent been able to call the list, making my app crash.
Activity with the Button
package com.example.repomax;
import android.app.Application;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatDialogFragment;
import androidx.fragment.app.FragmentManager;
import androidx.recyclerview.widget.RecyclerView;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Objects;
public class Binary extends AppCompatDialogFragment {
private PersonAdapter adapter;
private static final String TAG = "Binary Dialog";
public Binary(PersonAdapter adapter) {
this.adapter = adapter;
}
private void onClick(View v) {
if (classtup.getText().toString().isEmpty() || Sectiones.getText().toString().isEmpty()) {
Toast.makeText(getContext(), "Llene todos los campos", Toast.LENGTH_LONG).show();
} else {
ApplicationClass.materias.add(new Lasmaterias(classtup.getText().toString().trim(),
Sectiones.getText().toString().trim()));
adapter.addMaterias(new Lasmaterias(classtup.getText().toString().trim(),
Sectiones.getText().toString().trim()));
Toast.makeText(getContext(), "Clase Registrada", Toast.LENGTH_SHORT).show();
classtup.setText(null);
Sectiones.setText(null);
saveData();
dismiss();
}
}
public void saveData
public interface OnInputSelected {
void SendInput(String input);
}
public OnInputSelected monInputSelected;
//Widgets
private
RecyclerView.Adapter myAdapter;
TextView Title;
EditText classtup, Sectiones;
Button addud;
Planes planes;
FragmentManager fragmentManager;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_binary, container, false);
myAdapter = new PersonAdapter(getContext(), ApplicationClass.materias);
classtup = view.findViewById(R.id.classtup);
Sectiones = view.findViewById(R.id.Sectiones);
fragmentManager = getParentFragmentManager();
planes = (Planes) fragmentManager.findFragmentById(R.id.Planes);
addud = view.findViewById(R.id.addud);
addud.setOnClickListener(this::onClick);
return view;
}
}
FragmentActivity with the RecyclerView:
package com.example.repomax;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import com.google.gson.Gson;
import java.util.ArrayList;
public class Planes extends Fragment {
private static final String TAG = "Planes fragment";
RecyclerView recyclerView;
RecyclerView.Adapter myAdapter;
RecyclerView.LayoutManager layoutManager;
View view;
Button fab;
public Planes() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_planes, container, false);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
recyclerView = view.findViewById(R.id.list);
recyclerView.setHasFixedSize(true);
layoutManager = new LinearLayoutManager(this.getActivity());
recyclerView.setLayoutManager(layoutManager);
myAdapter = new PersonAdapter(getContext(), ApplicationClass.materias);
recyclerView.setAdapter(myAdapter);
fab = view.findViewById(R.id.fab);
fab.setOnClickListener(v -> {
Log.d(TAG, "onClick: Abriendo Ventanilla");
Binary dialog = new Binary((PersonAdapter) myAdapter);
dialog.setTargetFragment(Planes.this, 1);
dialog.show(getParentFragmentManager(), "Binary");
});
}
}
And finally the adapter:
package com.example.repomax;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
public class PersonAdapter extends RecyclerView.Adapter<PersonAdapter.ViewHolder> {
private ArrayList<Lasmaterias> materias;
private Context context;
private PersonAdapter adapter;
public PersonAdapter(Context context, ArrayList<Lasmaterias> list) {
this.context = context;
this.materias = list;
}
public void addMaterias(Lasmaterias lasmaterias) {
notifyDataSetChanged();
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView tvName;
TextView tvGroup;
public ViewHolder(#NonNull View itemView) {
super(itemView);
tvName = itemView.findViewById(R.id.tvName);
tvGroup = itemView.findViewById(R.id.TvPass);
itemView.setOnClickListener(v -> {
});
}
}
#NonNull
#Override
public PersonAdapter.ViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.class_item, viewGroup, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull PersonAdapter.ViewHolder viewHolder, int position) {
viewHolder.itemView.setTag(materias.get(position));
viewHolder.tvName.setText(materias.get(position).getName());
viewHolder.tvGroup.setText(materias.get(position).getTelNr());
}
#Override
public int getItemCount() {
return materias.size();
}
}