android:用Sharedpreferences保存和读取数据

一，代码：

xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activity.PreferenceActivity">

    <Button
        android:id="@+id/buttonsave"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="168dp"
        android:layout_marginTop="30dp"
        android:layout_marginEnd="155dp"
        android:layout_marginBottom="653dp"
        android:text="保存"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/buttonread"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="174dp"
        android:layout_marginTop="65dp"
        android:layout_marginEnd="149dp"
        android:layout_marginBottom="539dp"
        android:text="读取"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/buttonsave" />
</androidx.constraintlayout.widget.ConstraintLayout>

java:

package com.example.okdemo1.activity;

import android.app.ActivityOptions;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

import com.example.imagelib.ImageListActivity;
import com.example.okdemo1.MainActivity;
import com.example.okdemo1.R;

public class PreferenceActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_preference);

        //给按钮增加点击事件
        Button myButton = findViewById(R.id.buttonsave);
        myButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 处理点击事件
                //获取一个文件名为userInfo、权限为private的xml文件的SharedPreferences对象
                SharedPreferences sharedPreferences = getSharedPreferences("userInfo", MODE_PRIVATE);
                //得到SharedPreferences.Editor对象，并保存数据到该对象中
                SharedPreferences.Editor editor = sharedPreferences.edit();
                //保存key-value对到文件中
                editor.putInt("id", 12345);
                editor.putString("name", "总统秘书王富贵");
                editor.commit();
            }
        });

        //给按钮增加点击事件
        Button readButton = findViewById(R.id.buttonread);
        readButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 处理点击事件
                SharedPreferences sharedPreferences = getSharedPreferences("userInfo", MODE_PRIVATE);
                //读取数据
                int id = sharedPreferences.getInt("id", 0);
                String name = sharedPreferences.getString("name", "");
                //打印已读取数据
                Log.d("id",String.valueOf(id));
                Log.d("name",name);
            }
        });

    }
}

二，测试效果

三，查看文件在手机文件系统中保存的位置:

1,打开设备浏览器

2,文件路径:/data/data/包名/shared_prefs/