I'm new to Programming and to Android and have please a question. I have just easy app to insert, delete and update cars. I create an interface to communicate the RecyclerAdapter to the Fragments. Insert and delete cars work without problemes, however when I update the instance it will be not changed. To make it more clearly,the user has a button "updateButtonOnRecyclerView" on RecyclerView and when he clicks it,he get the UpdateFragment where he can update the instance and finally he clicks the button "updateButtonOnFragment" to save the updates.
I hope that someone can help me. thanks a lot.
UpdateFragment
public class UpdateFragment extends Fragment {
private EditText modelUpdate;
private EditText colorUpdate;
private EditText dplUpdate;
private EditText priceUpdate;
private EditText descriptionUpdate;
private Button updateButtonOnFragment;
private MyViewModel myViewModel;
public UpdateFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view= inflater.inflate(R.layout.fragment_update, container, false);
modelUpdate=view.findViewById(R.id.input_model_update);
colorUpdate=view.findViewById(R.id.input_color_update);
priceUpdate=view.findViewById(R.id.input_price_update);
dplUpdate=view.findViewById(R.id.input_dpl_update);
descriptionUpdate=view.findViewById(R.id.input_description_update);
MyViewModel myViewModel= new ViewModelProvider(this).get(MyViewModel.class);
updateButtonOnFragment =view.findViewById(R.id.btnUpdate);
updateButtonOnFragment.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String model=modelUpdate.getText().toString();
String color=colorUpdate.getText().toString();
String price=priceUpdate.getText().toString();
String dpl=dplUpdate.getText().toString();
String description=descriptionUpdate.getText().toString();
// create an instance of car
Car car = new Car();
car.setCarModel(model);
car.setCarColor(color);
car.setCarDescription(description);
car.setCarDpl(dpl);
car.setCarPrice(price);
myViewModel.updateCar(car);
MainActivity.fragmentManager.beginTransaction().replace(R.id.container,new BaseFragment(),null).commit();
}
});
return view;
}
}
RecyclerAdapter
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MyViewHolder> {
private List<Car>list;
private Context context;
private MyViewModel myViewModel;
private CarAdapterEvent carAdapterEvent;
//Constructor
public RecyclerAdapter(List<Car> list,Context context,CarAdapterEvent carAdapterEvent ) {
this.list = list;
this.context=context;
this.carAdapterEvent=carAdapterEvent;
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.car_item,parent,false);
MyViewHolder myViewHolder = new MyViewHolder(view);
context=parent.getContext();
return myViewHolder;
}
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
Car car = list.get(position);
holder.tvModel.setText(car.getCarModel());
holder.tvColor.setText(car.getCarColor());
holder.tvDpl.setText(car.getCarDpl());
holder.tvDescription.setText(car.getCarDescription());
holder.tvPrice.setText(car.getCarPrice());
}
@Override
public int getItemCount() {
if(list !=null)
{
return list.size();
}
else return 0;
}
public void setData(List<Car>list){
this.list=list;
notifyDataSetChanged();
}
// generate ViewHolder
public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView tvModel;
TextView tvColor;
TextView tvDpl;
TextView tvDescription;
TextView tvPrice;
Button btnDelete;
Button updateButtonOnRecyclerView;
// Constructor of ViewHolder
public MyViewHolder(@NonNull View itemView) {
super(itemView);
// Inflate the views
tvModel=itemView.findViewById(R.id.model);
tvColor=itemView.findViewById(R.id.color);
tvDescription=itemView.findViewById(R.id.description);
tvDpl=itemView.findViewById(R.id.dpl);
tvPrice=itemView.findViewById(R.id.price);
btnDelete=itemView.findViewById(R.id.btn_delete);
updateButtonOnRecyclerView =itemView.findViewById(R.id.btn_update);
// Listener for Delete button
btnDelete.setOnClickListener(this);
btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int position = getAdapterPosition();
carAdapterEvent.onDeleteClicked(list.get(position));
}
});
//Listener for update button
updateButtonOnRecyclerView.setOnClickListener(this);
updateButtonOnRecyclerView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int position = getAdapterPosition();
carAdapterEvent.onUpdateClicked(list.get(position));
}
});
}
private void CreateAlertDialoge()
{
AlertDialog.Builder builder =new AlertDialog.Builder(context);
builder.setMessage("Are you sure to delete");
builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Car car = new Car();
int ID=list.get(getAdapterPosition()).getCarId();
car.setCarId(ID);
myViewModel.deleteCar(car);
MainActivity.fragmentManager.beginTransaction().replace(R.id.container,new BaseFragment(),null).commit();
Toast.makeText(context, "Yes", Toast.LENGTH_SHORT).show();
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(context, "no", Toast.LENGTH_SHORT).show();
}
});
builder.create();
builder.show();
}
@Override
public void onClick(View v) { }
}
}
Interface for communication
public interface CarAdapterEvent {
void onDeleteClicked(Car car);
void onUpdateClicked(Car car);
}
BaseFragment
public class BaseFragment extends Fragment implements CarAdapterEvent {
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;
private List<Car>list=new ArrayList<>();
private MyViewModel myViewModel;
public RecyclerAdapter recyclerAdapter;
// Required empty public constructor
public BaseFragment() { }
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the layout for this fragment
View view= inflater.inflate(R.layout.fragment_base, container, false);
//Inflate recyclerView
recyclerView=view.findViewById(R.id.recyclerViewId);
// define and set LayoutManager
layoutManager= new GridLayoutManager(requireActivity(),2);
recyclerView.setLayoutManager(layoutManager);
//define and set RecyclerView Adapter
recyclerAdapter = new RecyclerAdapter(list, getContext(),this);
recyclerView.setAdapter(recyclerAdapter);
//observer
myViewModel= new ViewModelProvider(this).get(MyViewModel.class);
myViewModel.getGetAllCars().observe(getViewLifecycleOwner(), new Observer<List<Car>>() {
@Override
public void onChanged(List<Car> cars) {
recyclerAdapter.setData(cars);
}
});
return view;
}
@Override
public void onDeleteClicked(Car car) {
myViewModel.deleteCar(car);
MainActivity.fragmentManager.beginTransaction().replace(R.id.container,new BaseFragment(),null).commit();
}
@Override
public void onUpdateClicked(Car car) {
myViewModel.updateCar(car);
MainActivity.fragmentManager.beginTransaction().replace(R.id.container,new UpdateFragment(),null).commit();
}
}
