用单例封装 SharedPreferences

自己封装的 SharedPreferences，很简单的封装，直接上代码

public class SPManager {    private static final String ACCOUNT = "account";    private static final String PASSWORD = "password";    private static final String USER_ID = "user_id";    private static final String USER_NAME = "user_name";    private static final String LAST_DAY = "last_day";    private static Context mContext;    private SharedPreferences sp;    private SharedPreferences.Editor editor;    private SPManager() {        sp = PreferenceManager.getDefaultSharedPreferences(mContext);        editor = sp.edit();    }    public static SPManager getInstance(Context context) {        //使用 ApplicationContext 防止内存泄漏        mContext = context.getApplicationContext();        return Singer.sputils;    }    //使用静态内部类的方式创建单例    private static class Singer {        static SPManager sputils = new SPManager();    }        //封装 SharedPreferences 的各种 put 方法    //返回 this ，方便链式调用    private SPManager put(String key, Object value) {        if (value instanceof String) {            editor.putString(key, (String) value);        } else if (value instanceof Integer) {            editor.putInt(key, (Integer) value);        } else if (value instanceof Boolean) {            editor.putBoolean(key, (Boolean) value);        } else if (value instanceof Long) {            editor.putLong(key, (Long) value);        } else if (value instanceof Float) {            editor.putFloat(key, (Float) value);        }        return this;    }    //封装 SharedPreferences 的各种 get 方法    //使用泛型，调用时不用再强制转换    private <T> T get(String key, Object defValue) {        if (defValue instanceof String) {            return (T) sp.getString(key, (String) defValue);        } else if (defValue instanceof Integer) {            return (T) Integer.valueOf(sp.getInt(key, (Integer) defValue));        } else if (defValue instanceof Boolean) {            return (T) Boolean.valueOf(sp.getBoolean(key, (Boolean) defValue));        } else if (defValue instanceof Long) {            return (T) Long.valueOf(sp.getLong(key, (Long) defValue));        } else if (defValue instanceof Float) {            return (T) Float.valueOf(sp.getFloat(key, (Float) defValue));        }        return null;    }    //以下几个方法是写好的固定的要保存和获取的数据，方便直接调用    public String getAccount() {        return get(ACCOUNT, "");    }    public SPManager putAccount(String account) {        return put(ACCOUNT, account);    }    public String getPassword() {        return get(PASSWORD, "");    }    public SPManager putPassword(String password) {        return put(PASSWORD, password);    }    public int getUserId() {        return get(USER_ID, 0);    }    public SPManager putUserId(int userId) {        return put(USER_ID, userId);    }    public String getUserName() {        return get(USER_NAME, "");    }    public SPManager putUserName(String userName) {        return put(USER_NAME, userName);    }    public int getLastDate() {        return get(LAST_DAY, -1);    }    public SPManager putLastDate(int lastDate) {        return put(LAST_DAY, lastDate);    }    public void apply() {        editor.apply();    }}