Como atualizar dados em uma caixa de diálogo personalizada

1. criar a caixa de diálogo
2. definir texto padrão em textos de edição
3. definir onClickListener para botões

public class MyDialog extends DialogFragment {

   public static final String SimpleName = MyDialog.class.getSimpleName();
   private EditText name,category, quantity, importance;
   private Button update, positive, negative;
   private Builder builder;

    private static MyDialog instance = new MyDialog();

    public static MyDialog getInstance(){
        return instance;
    }

   @Override
    public void onCreate(Bundle savedInstanceState) {
        this.setCancelable(true);

        if (savedInstanceState != null) {
            if (builder != null) {
                builder = savedInstanceState.getParcelable(Builder.class.getSimpleName());
            }
        }
        setRetainInstance(true);
        super.onCreate(savedInstanceState);
    }

    @NonNull
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        Dialog dialog = super.onCreateDialog(savedInstanceState);
        // make the dialog's default background transparent so that you can customize the window
        dialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
        dialog.getWindow().requestFeature(Window.FEATURE_NO_TITLE);
        return dialog;
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.my_dialog_layout, container, false);
    }

    @Override
    public void onViewCreated(View view, @Nullable final Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        initViews(view);
        if (builder != null) {

            if (builder.getTextName() != null) {
                name.setText(builder.getTextName());
            }
            if (builder.getTextCategory() != null) {
                category.setText(builder.getTextCategory());
            }
            if (builder.getTextQuantity() != null) {
                quantity.setText(builder.getTextQuantity());
            }
            if (builder.getTextImportance() != null) {
                importance.setText(builder.getTextImportance());
            }



            update.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    builder.getOnUpdateClicked().OnClick(view, getDialog());
                }
            });

            positive.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                   builder.getOnPositiveClicked().OnClick(view, getDialog());
                }
            });

            negative.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                  builder.getOnNegativeClicked().OnClick(view, getDialog());
                }
            });

        }
    }

    private void initViews(View view) {       
        name = (EditText) view.findViewById(R.id.editText_name);
        category = (EditText) view.findViewById(R.id. editText_category);
        quantity = (EditText) view.findViewById(R.id. editText_quantity);
        importance = (EditText) view.findViewById(R.id.editText_importance);
        update = (Button) view.findViewById(R.id.update);
        positive = (Button) view.findViewById(R.id.positive);
        negative = (Button) view.findViewById(R.id.negative);

    }

    private Dialog show(Activity activity, Builder builder) {             
         this.builder = builder;
         if (!isAdded()){
             show(((AppCompatActivity) activity).getSupportFragmentManager(), SimpleName);
         }
         return getDialog();
     }

    public static class Builder implements Parcelable  {

        private OnPositiveClicked onPositiveClicked;
        private OnNegativeClicked onNegativeClicked;
        private OnUpdateClicked onUpdateClicked;

        private textName;
        private textCategory;
        private textQuantity;
        private textImportance;

        private Context context;

        protected Builder(Parcel in) {
            textName = in.readString();
            textCategory = in.readString();
            textQuantity = in.readString();
            textImportance = in.readString();
        }

        public static final Creator<Builder> CREATOR = new Creator<Builder>() {
            @Override
            public Builder createFromParcel(Parcel in) {
                return new Builder(in);
            }

            @Override
            public Builder[] newArray(int size) {
                return new Builder[size];
            }
        };

        public Context getContext() {
            return context;
        }

        public Builder setActivity(Context context) {
            this.context = context;
            return this;
        }

        public Builder(Context context) {
            this.context = context;
        }

        public Builder setTextName(String textName) {
            this.textName = textName;
            return this;
        }

        public String getTextName() {
            return textName;
        }

        public Builder setTextCategory(String textCategory) {
            this.textCategory = textCategory;
            return this;
        }

        public String getTextCategory() {
            return textCategory;
        }

        public Builder setTextQuantity(String textQuantity) {
            this.textQuantity = textQuantity;
            return this;
        }

        public String getTextQuantity() {
            return textQuantity;
        }

        public Builder setTextImportance(String textImportance) {
            this.textImportance = textImportance;
            return this;
        }

        public String getTextImportance() {
            return textImportance;
        }


        public OnPositiveClicked getOnPositiveClicked() {
            return onPositiveClicked;
        }

        public Builder setOnPositiveClicked(OnPositiveClicked onPositiveClicked) {
            this.onPositiveClicked = onPositiveClicked;
            return this;
        }

        public OnNegativeClicked getOnNegativeClicked() {
            return onNegativeClicked;
        }

        public Builder setOnNegativeClicked(OnNegativeClicked onNegativeClicked) {
            this.onNegativeClicked = onNegativeClicked;
            return this;
        }

        public OnUpdateClicked getOnUpdateClicked() {
            return onUpdateClicked;
        }

        public Builder setOnUpdateClicked(OnUpdateClicked onUpdateClicked) {
            this.onUpdateClicked = onUpdateClicked;
            return this;
        }

        public Builder build() {
            return this;
        }

        public Dialog show() {
            return getInstance().show(((Activity) context), this);
        }

        @Override
        public int describeContents() {
            return 0;
        }

        @Override
        public void writeToParcel(Parcel parcel, int i) {
            parcel.writeString(textName);
            parcel.writeString(textCategory);
            parcel.writeString(textQuantity);
            parcel.writeString(textImportance);
        }

    }

    public interface OnPositiveClicked {
        void OnClick(View view, Dialog dialog);
    }

    public interface OnNegativeClicked {
        void OnClick(View view, Dialog dialog);
    }


}

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            MyDialog.Builder dialog=null;

            // TODO get the strings from database at the position i
            String name = 
            String category = 
            String quantity = 
            String importance = 

            dialog.setTextName(name)
                .setTextCategory(category)
                .setTextQuantity(quantity)
                .setTextImportance(importance)
                .setOnPositiveClicked(new MyDialog.OnPositiveClicked() { 
                             @Override
                            public void OnClick(View view, Dialog dialog) {

                            }
                        })
                .setOnNegativeClicked(new MyDialog.OnNegativeClicked() { 
                            @Override
                            public void OnClick(View view, Dialog dialog) {

                            }
                        })
                .setOnUpdateClicked(new MyDialog.OnUpdateClicked() { 
                            @Override
                            public void OnClick(View view, Dialog dialog) {
                                // TODO update database here
                            }
                        })

                .build();
                dialog.show();
        }
    });