Android的SharedPreferences实用技巧

SharedPreferences也是一种轻型的数据存储方式，它的本质是基于XML文件存储key-value键值对数据，通常用来存储一些简单的配置信息。其存储位置在/data/data/<包名>/shared_prefs目录下。SharedPreferences对象本身只能获取数据而不支持存储和修改，存储修改是通过Editor对象实现。实现SharedPreferences存储的步骤如下：
一、根据Context获取SharedPreferences对象
二、利用edit()方法获取Editor对象。
三、通过Editor对象存储key-value键值对数据。
四、通过commit()方法提交数据。

public class MainActivity extends Activity {    @Override    public void onCreate(Bundle savedInstanceState) {       super.onCreate(savedInstanceState);       setContentView(R.layout.main);              //获取SharedPreferences对象       Context ctx = MainActivity.this;              SharedPreferences sp = ctx.getSharedPreferences("pref", MODE_PRIVATE);       //存入数据       Editor editor = sp.edit();       editor.putString("name", "jeff");       editor.putInt("score", 0);       editor.putBoolean("playagain", true);       editor.commit();           }}

上面的例子使用起来比较麻烦，这里给出一种简单的封装方案

import java.util.Map.Entry;import android.content.ContentValues;import android.content.Context;import android.content.SharedPreferences;public class MyPreference {private static final String PREFERENCE_NAME = "my.db";private SharedPreferences mPreference;public MyPreference(Context ctx) {mPreference = ctx.getApplicationContext().getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);}public boolean putStringAndCommit(String key, String value) {return mPreference.edit().putString(key, value).commit();}public boolean putIntAndCommit(String key, int value) {return mPreference.edit().putInt(key, value).commit();}public boolean putBooleanAndCommit(String key, boolean value) {return mPreference.edit().putBoolean(key, value).commit();}public boolean putIntAndCommit(ContentValues values) {SharedPreferences.Editor editor = mPreference.edit();for (Entry<String, Object> value : values.valueSet()) {editor.putString(value.getKey(), value.getValue().toString());}return editor.commit();}public String getString(String key) {return getString(key, "");}public String getString(String key, String defValue) {return mPreference.getString(key, defValue);}public int getInt(String key) {return getInt(key, -1);}public int getInt(String key, int defValue) {return mPreference.getInt(key, defValue);}public boolean getBoolean(String key) {return getBoolean(key, false);}public boolean getBoolean(String key, boolean defValue) {return mPreference.getBoolean(key, defValue);}}

使用方式如下

public class MainActivity extends Activity {    @Override    public void onCreate(Bundle savedInstanceState) {       super.onCreate(savedInstanceState);       setContentView(R.layout.main);              MyPreference pref = new MyPreference(this);       pref.putStringAndCommit("name", "jeff");           }}