android中SharedPreferences的用法

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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>

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