SP的保存与显示:

xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    android:padding="15dp"
    tools:context=".datastorage.SharedPreferencesActivity">

    <EditText
        android:id="@+id/et_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="输入内容" />

    <Button
        android:id="@+id/btn_save"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="保存" />
    <Button
        android:id="@+id/btn_show"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="显示" />
    <TextView
        android:id="@+id/tv_content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"/>
</LinearLayout>

activity:

package com.example.lineralayout.datastorage;

import androidx.appcompat.app.AppCompatActivity;

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

import com.example.lineralayout.R;

public class SharedPreferencesActivity extends AppCompatActivity {
    private EditText mEtName;
    private Button mBtnSave,mBtnShow;
    private TextView mTvContent;
    private SharedPreferences mSharedPreferences;
    private SharedPreferences.Editor mEditor;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_shared_preferences);
        mSharedPreferences = getSharedPreferences("data",MODE_PRIVATE);
        mEditor = mSharedPreferences.edit();
        mEtName = findViewById(R.id.et_name);
        mBtnSave = findViewById(R.id.btn_save);
        mBtnShow = findViewById(R.id.btn_show);
        mTvContent = findViewById(R.id.tv_content);
        mBtnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //获取EditText里面的内容
                mEditor.putString("name",mEtName.getText().toString());
                //提交
                mEditor.apply();
            }
        });
        mBtnShow.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mTvContent.setText(mSharedPreferences.getString("name",""));
            }
        });
    }

}