android中SharedPreferences的用法

SharedPreferences的用法非常简单，因为原理和Map差不多，所以下面给出一个参考程序：

MainActivity.java

import android.content.Context;
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 java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class MainActivity extends AppCompatActivity {
    SharedPreferences preferences;
    SharedPreferences.Editor editor;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        //获取只能被本应用程序读、写的SharedPreferences对象
        preferences = getSharedPreferences("raid", Context.MODE_WORLD_READABLE);
        editor = preferences.edit();
        Button write = (Button)findViewById(R.id.write);
        Button read = (Button)findViewById(R.id.read);
        final TextView txt = (TextView)findViewById(R.id.txt);
        write.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                editor.putBoolean("booleanValue", true);
                editor.putFloat("floatValue", 12.5f);
                editor.putInt("intValue", 12);
                editor.putLong("longValue", 22222222);
                editor.putString("stringValue", getDateString());
                Set<String> set = new HashSet<String>();
                for(int i = 0; i < 3; i++) {
                    set.add("set"+i);
                }
                editor.putStringSet("setValue", set);
                editor.commit();
            }
        });

        read.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                StringBuilder sb = new StringBuilder();
                sb.append(preferences.getBoolean("booleanValue", false) + "\n");
                sb.append(preferences.getFloat("floatValue", 0.0f) + "\n");
                sb.append(preferences.getInt("intValue", 0) + "\n");
                sb.append(preferences.getLong("longValue", 0) + "\n");
                sb.append(preferences.getString("stringValue", null) + "\n");
                sb.append("the set is : " + "\n");
                Set<String> set = preferences.getStringSet("setValue", null);
                if(set != null) {
                    Iterator<String> iterator = set.iterator();
                    while(iterator.hasNext()) {
                        sb.append(iterator.next() + "\n");
                    }
                }
                txt.setText(sb.toString());
            }
        });
    }

    private String getDateString() {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日hh:mm:ss");
        return sdf.format(new Date());
    }

}

main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:gravity="center">

        <Button
            android:id="@+id/write"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/write"
            android:paddingRight="20dp"/>

        <Button
            android:id="@+id/read"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/read" />

    </LinearLayout>

    <TextView
        android:id="@+id/txt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>


</LinearLayout>