java - 为什么 SharedPreference 在 RecyclerView 中不起作用

Question

下面给出了 mainactivity 和 viewactivity 的代码。

MainActivity.java这里是mainActivity的代码

package com.example.calcul;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    SharedPreferences sharedPreferences;

    EditText nameET,itemET,priceET;
    String name,item,price;

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

        nameET=findViewById(R.id.NameET);
        itemET=findViewById(R.id.ItemET);
        priceET=findViewById(R.id.PriceET);

    }

    public void SubmitBT(View view) {

        name=nameET.getText().toString();
        item=itemET.getText().toString();
        price=priceET.getText().toString();

        class SaveData extends AsyncTask<Void, Void, Void>{

            @Override
            protected Void doInBackground(Void... voids) {
                Calculator calculator=new Calculator();

                calculator.setName(name);
                calculator.setItem(item);
                calculator.setPrice(price);

                DatabaseClient.getInstance(getApplicationContext()).appdatabase.calculatorDao().insertData(calculator);

                return null;

            }

            @Override
            protected void onPostExecute(Void aVoid) {
                super.onPostExecute(aVoid);

                Toast.makeText(MainActivity.this, "Saved", Toast.LENGTH_SHORT).show();
            }
        }
        if (name.equals("") && item.equals("") && price.equals("") ){

            Toast.makeText(this, "Please Enter your name and Item and Price ", Toast.LENGTH_SHORT).show();
        }

        else if (name.equals("") ){

            Toast.makeText(this, "Please Enter your name ", Toast.LENGTH_SHORT).show();
        }
        else if (item.equals("")){

            Toast.makeText(this, "Please Enter your  Item", Toast.LENGTH_SHORT).show();
        }
        else if (price.equals("")){

            Toast.makeText(this, "Please Enter your  Price", Toast.LENGTH_SHORT).show();

        }
        else{
            Intent intent=new Intent(this, ViewActivity.class);

            intent.putExtra("PriceKey",price);

            startActivity(intent);

            SaveData saveData =new SaveData();
            saveData.execute();
        }
    }

    public void PreviousViewBT(View view) {
        Intent intent=new Intent(this, ViewActivity.class);
        startActivity(intent);

    }
}

ViewActivity.java这里是查看activiy的代码

package com.example.calcul;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class ViewActivity extends AppCompatActivity {

    RecyclerView recyclerView;
    List<Calculator>calculators;

    String price;
    TextView priceTV;

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

        priceTV=findViewById(R.id.PriceTV);

        if (loadPrice() !=null){
            priceTV.setText("Price : "+loadPrice());

        }
        calculators =new ArrayList<>();

        recyclerView=findViewById(R.id.RecyclerViewID);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));

        price=getIntent().getStringExtra("PriceKey");

        //priceTV.setText("Total : "+price);

        savePrice (price);

        List<Calculator>calculators=DatabaseClient.getInstance(getApplicationContext()).appdatabase.calculatorDao().getData();
        CustomAdapter customAdapter =new CustomAdapter(this, calculators);
        recyclerView.setAdapter(customAdapter);

    }


    private void  savePrice(String price){

        SharedPreferences sharedPreferences=getSharedPreferences("Price",0);
        SharedPreferences.Editor editor=sharedPreferences.edit();
        editor.putString("priceKey",price);
        editor.commit();

    }

    private String loadPrice(){

        SharedPreferences sharedPreferences=getSharedPreferences("Price",0);
        String price=sharedPreferences.getString("priceKey",null);
        return price;

    }

    public void NewBT(View view) {

        Intent  intent=new Intent(this,MainActivity.class);
        startActivity(intent);

    }
}

这里没有任何运行时错误。但不工作共享Prefernce。我的意思是价格的值没有保存。当提交所有信息时，recyclerview 正在工作。但价格并不能节省。

Answer 1

如果我理解正确，那么您可以滚动 recyclerView 从而更改价格，但我没有看到处理元素滚动的代码。请提供更多信息。