使用SharedPreferences将姓名和年龄信息保存在文件中，并读取信息

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:id="@+id/activity_main"
 5     android:layout_width="match_parent"
 6     android:layout_height="match_parent"
 7     android:orientation="vertical"
 8     tools:context="com.example.zhoushasha.myapplication.MainActivity">
 9 
10     <EditText
11         android:id="@+id/et1"
12         android:layout_width="wrap_content"
13         android:layout_height="wrap_content"
14         android:hint="请输入姓名"
15         android:textSize="25dp"/>
16     <EditText
17         android:id="@+id/et2"
18         android:layout_width="wrap_content"
19         android:layout_height="wrap_content"
20         android:hint="请输入年龄"
21         android:textSize="25dp"/>
22     <LinearLayout
23         android:layout_width="wrap_content"
24         android:layout_height="wrap_content"
25         android:layout_weight="0">
26         <Button
27             android:id="@+id/bt1"
28             android:layout_width="208dp"
29             android:layout_height="wrap_content"
30             android:text="写入"
31             android:textSize="25dp"/>
32 
33         <Button
34             android:id="@+id/bt2"
35             android:layout_width="168dp"
36             android:layout_height="wrap_content"
37             android:text="读出"
38             android:textSize="25dp"/>
39     </LinearLayout>
40 </LinearLayout>

 1 package com.example.zhoushasha.myapplication;
 2 
 3 import android.app.Activity;
 4 import android.content.Context;
 5 import android.content.SharedPreferences;
 6 import android.content.SharedPreferences.Editor;
 7 import android.support.v7.app.AppCompatActivity;
 8 import android.os.Bundle;
 9 import android.view.View;
10 import android.widget.Button;
11 import android.widget.EditText;
12 import android.widget.Toast;
13 
14 public class MainActivity extends AppCompatActivity {
15     private EditText nameText;
16     private EditText ageText;
17 
18     @Override
19     protected void onCreate(Bundle savedInstanceState) {
20         super.onCreate(savedInstanceState);
21         setContentView(R.layout.activity_main);
22         nameText = (EditText)this.findViewById(R.id.et1);
23         ageText = (EditText)this.findViewById(R.id.et2);
24         Button button = (Button)this.findViewById(R.id.bt1);
25         Button showButton = (Button)this.findViewById(R.id.bt2);
26         button.setOnClickListener(listener);
27         showButton.setOnClickListener(listener);
28 
29         // 回显
30         SharedPreferences sharedPreferences=getSharedPreferences("王艳",
31                 Activity.MODE_PRIVATE);
32         String nameValue = sharedPreferences.getString("name", "");
33         int ageValue = sharedPreferences.getInt("age",18);
34         nameText.setText(nameValue);
35         ageText.setText(String.valueOf(ageValue));
36     }
37 
38     private View.OnClickListener listener = new View.OnClickListener(){
39         public void onClick(View v) {
40             Button button = (Button)v;
41             //ljq123文件存放在/data/data/<package name>/shared_prefs目录下
42             SharedPreferences sharedPreferences=getSharedPreferences("王艳",
43                     Activity.MODE_PRIVATE );
44             switch (button.getId()) {
45                 case R.id.bt1:
46                     String name = nameText.getText().toString();
47                     int age = Integer.parseInt(ageText.getText().toString());
48                     Editor editor = sharedPreferences.edit(); //获取编辑器
49                     editor.putString("name","王艳");
50                     editor.putInt("age", age);
51                     editor.commit();//提交修改
52                     Toast.makeText( MainActivity.this, "保存成功", Toast.LENGTH_LONG).show();
53                     break;
54                 case R.id.bt2:
55                     String nameValue = sharedPreferences.getString("name", "");
56                     int ageValue = sharedPreferences.getInt("age", 1);
57                     Toast.makeText(MainActivity.this,"姓名："+nameValue + "，年龄：" + ageValue,Toast.LENGTH_LONG).show();
58 
59                     break;
60             }
61         }
62     };
63 }


这样就可以使程序正常运行。