SharedPreferences是Android平台上一个轻量级的存储类，用来保存应用的一些常用配置，比如Activity状态，Activity暂停时，将此activity的状态保存到SharedPereferences中；当Activity重载，系统回调方法onSaveInstanceState时，再从SharedPreferences中将值取出……。下面通过一个小小的案例，分享一下我之前做的。
1、最终效果图
大致就是通过SharedPreferences存储类创建一个配置文件（这里是通过按钮去触发的），然后向配置文件中写入配置信息，最后就是读配置中“键”对应的“值”（这里通过按钮触发将读到的值显示出来）。还是比较简单，很容易的。
2、布局文件
activity_main.xml：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="thonlon.example.cn.sharedpreferencesdemo.MainActivity">
<Button
android:id="@+id/btn_create"
android:layout_width="396dp"
android:layout_height="46dp"
android:text="@string/btn_create_sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<Button
android:id="@+id/btn_getInfo"
android:layout_width="396dp"
android:layout_height="46dp"
android:layout_marginLeft="0dp"
android:text="@string/btn_getInfo_sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.1" />
<TextView
android:id="@+id/textView1"
android:layout_width="80dp"
android:layout_height="20dp"
android:background="@color/colorPrimary"
android:text="英文显示:"
android:textAlignment="center"
android:textColor="@color/colorWhite"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.465" />
<TextView
android:id="@+id/textView2"
android:layout_width="80dp"
android:layout_height="20dp"
android:background="@color/colorPrimary"
android:text="中文显示:"
android:textAlignment="center"
android:textColor="@color/colorWhite"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.205" />
<TextView
android:id="@+id/tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.244" />
<TextView
android:id="@+id/tv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.53" />
</android.support.constraint.ConstraintLayout>
3、activity文件
MainActivity.java
package thonlon.example.cn.sharedpreferencesdemo;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private SharedPreferences sharedPreferences;
private Button btn_create, btn_getInfo;
private TextView textView1, textView2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_create = (Button) findViewById(R.id.btn_create);
btn_getInfo = (Button) findViewById(R.id.btn_getInfo);
textView1 = (TextView) findViewById(R.id.tv1);
textView2 = (TextView) findViewById(R.id.tv2);
// 设置配置文件的名称和配置文件的被访问权限
sharedPreferences = getSharedPreferences("config", MODE_ENABLE_WRITE_AHEAD_LOGGING);
btn_create.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
write();
}
private void write() {
//得到配置编辑器
SharedPreferences.Editor edit = sharedPreferences.edit();
//写入配置信息到配置文件中
edit.putString("Chinese", "SharedPreferences是Android平台上一个轻量级的存储类。");
edit.putString("English", "SharedPreferences is a lightweight storage class on the Android platform to save some of the common configuration of the application.");
//注意以上只是将配置信息写入了内存
edit.commit();//提交内存配置信息到本地
Toast.makeText(getApplicationContext(), "成功创建文件", Toast.LENGTH_LONG).show();
}
});
btn_getInfo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
read();
}
private void read() {
String chinese_info = sharedPreferences.getString("Chinese", "");
String english_info = sharedPreferences.getString("English", "");
textView1.setText(chinese_info);
textView2.setText(english_info);
}
});
}
}
4、源码下载
百度云下载链接：https://pan.baidu.com/s/1PRY5fdlAt5ZSl05NGniWrw 密码：tpr0