布局文件activity_main.xml

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<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:paddingHorizontal="10dp"
    android:gravity="center">
    <EditText
        android:id="@+id/et_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="名称"
        android:inputType="text"
        android:paddingVertical="10dp"
        android:paddingStart="10dp"
        android:textSize="26sp"/>
    <EditText
        android:id="@+id/et_num"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/et_name"
        android:layout_marginTop="20dp"
        android:hint="数量"
        android:inputType="text"
        android:paddingVertical="10dp"
        android:paddingStart="10dp"
        android:textSize="26sp"/>

    <LinearLayout
        android:id="@+id/lyt_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/et_num"
        android:layout_marginTop="20dp"
        android:gravity="center">

        <Button
            android:id="@+id/btn_save"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_marginHorizontal="2dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:text="保存"
            android:textSize="26sp" />

        <Button
            android:id="@+id/btn_read"
            android:layout_width="0dp"
            android:layout_marginHorizontal="2dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:text="读取"
            android:textSize="26sp" />

        <Button
            android:id="@+id/btn_remove"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_marginHorizontal="2dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:text="删除"
            android:textSize="26sp" />

        <Button
            android:id="@+id/btn_clear"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_marginHorizontal="2dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:text="清除"
            android:textSize="26sp" />
    </LinearLayout>


    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/lyt_btn"
        android:layout_marginTop="20dp"
        android:maxLines="5"
        android:paddingVertical="20dp"
        android:paddingStart="10dp"
        android:textSize="30sp"/>


</RelativeLayout>

Java代码MainActivity.java

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package com.example.datademo;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {
    private EditText mEtName, mEtNumber;
    private Button mBtnSave, mBtnRead, mBtnRemove, mBtnClear;
    private TextView mTv;
    private SharedPreferences sharedPreferences;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mBtnSave = findViewById(R.id.btn_save);
        mBtnRead = findViewById(R.id.btn_read);
        mBtnRemove = findViewById(R.id.btn_remove);
        mBtnClear = findViewById(R.id.btn_clear);
        mTv = findViewById(R.id.tv);
        mEtName = findViewById(R.id.et_name);
        mEtNumber = findViewById(R.id.et_num);
        sharedPreferences = getSharedPreferences("Order", MODE_PRIVATE);

        mBtnSave.setOnClickListener((View view)->dataSave());
        mBtnRead.setOnClickListener((View view)->dataRead());
        mBtnRemove.setOnClickListener((View view)->dataRemove("name"));
        mBtnClear.setOnClickListener((View view)->dataClear());
    }

    private void dataClear() {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear();
        editor.apply();
    }

    private void dataRemove(String name) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.remove(name);
        editor.apply();
    }

    private void dataSave() {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        String name = mEtName.getText().toString();
        editor.putString("name", name);
        String numberText = mEtNumber.getText().toString();
        int number = Integer.parseInt(numberText);
        editor.putInt("number",number);
        editor.putBoolean("pay", true);

        editor.apply();
    }

    private void dataRead() {
        String name = sharedPreferences.getString("name","defaultName");
        int number = sharedPreferences.getInt("number", 0);
        boolean pay = sharedPreferences.getBoolean("pay", false);

        mTv.append(String.format("%s---%d---%s\n", name,number,pay));
    }
}

运行结果

输入如图所示，使用以下操作，分别得到三种输出结果在TextView中显示

  1. 保存->读取
  2. 删除->读取
  3. 清除->读取