关于sharedpreferences的应用

  android中数据储存的方式一般有5种,
  1.保存在data/data/包名下
  2.保存在sd卡中
  3.保存在中
  4.保存在SharedPreferences数据库中
  5.保存在contentprovider中

  今天来着重介绍一下关于sp的使用问题:

1.获取SharedPreferences对象

sp = getSharedPreferences("config", MODE_PRIVATE);
    目录：/data/data/包名/shared_prefs/config.xml

2.保存数据

sp.edit().putString("username","晋锐").putInt("age",23).commit();

3.删除数据

删除一个
    sp.edit().remove("age").commit();
删除全部
    sp.edit().clear().commit();

4. 获取数据

String username = sp.getString("username",defValue);

附赠常用的 SpUtil工具类 ：

public enum SharedPreferenceUtil {
    INSTANCE;

    private final String PREF_NAME = "CommonSharedPreference";
    protected SharedPreferences mSettings;
    protected SharedPreferences.Editor mEditor;
    private Context mContext;

    // 初始化构造
    SharedPreferenceUtil() {
        mContext = HomeApplication.getInstance().getApplicationContext();
        if (mContext == null) {
            return;
        }
        mSettings = mContext.getSharedPreferences(PREF_NAME, MODE_PRIVATE);
        mEditor = mSettings.edit();

    }

    public boolean commit() {
        return mEditor.commit();
    }

    public String getString(String key) {
        return mSettings.getString(key, "");
    }

    public String getString(String key, String defaultValue) {
        return mSettings.getString(key, defaultValue);
    }

    public void saveString(String key, String value) {
        mEditor.putString(key, value);
        mEditor.commit();
    }

    public boolean getBoolean(String key, boolean defValue) {
        return mSettings.getBoolean(key, defValue);
    }

    public void saveBoolean(String key, boolean value) {
        mEditor.putBoolean(key, value);
        mEditor.commit();
    }

    public int getInt(String key, int defValue) {
        return mSettings.getInt(AccountAgent.getUserName() + key, defValue);
    }

    public void saveInt(String key, int value) {
        mEditor.putInt(AccountAgent.getUserName() + key, value);
        mEditor.commit();
    }

    public long getLong(String key, long defValue) {
        return mSettings.getLong(AccountAgent.getUserName() + key, defValue);
    }

    public void saveLong(String key, long value) {
        mEditor.putLong(AccountAgent.getUserName() + key, value);
        mEditor.commit();
    }
    public Object getObject(String key, Type type) {
        String json = getString(key);
        if (!TextUtils.isEmpty(json)) {
            try {
                Gson gson = new Gson();
                return gson.fromJson(json, type);
            } catch (JsonParseException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    public void saveObject(String key, Object obj) {
        Gson gson = new Gson();
        String objStr = gson.toJson(obj);
        saveString(key, objStr);
    }
    public void removeKey(String key) {
        mEditor.remove(key);
        mEditor.commit();
    }

    public void clearKeys() {
        mEditor.clear();
        mEditor.commit();
    }

    public boolean isContains(String key) {
        return mSettings.contains(key);
    }
}