SharedPreferences-SPUtil封装

public class SPUtil {

    private static Application app;
    private static volatile SPUtil singleton;



    private SPUtil(Application app) {
        SPUtil.app = app;
    }

    public static SPUtil init(Application app) {
        if (singleton == null) {
            synchronized (SPUtil.class) {
                if (singleton == null) {
                    singleton = new SPUtil(app);
                }
            }
        }
        return singleton;
    }

    /**
     * 保存数据的方法，拿到数据保存数据的基本类型，然后根据类型调用不同的保存方法
     *
     * @param key
     * @param obj
     */
    public static void put(String key, Object obj) {
        SharedPreferences sharedPreferences = app.getSharedPreferences(Constant.APP_ID, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        if (obj instanceof String) {
            editor.putString(key, (String) obj);
        } else if (obj instanceof Integer) {
            editor.putInt(key, (Integer) obj);
        } else if (obj instanceof Boolean) {
            editor.putBoolean(key, (Boolean) obj);
        } else if (obj instanceof Float) {
            editor.putFloat(key, (Float) obj);
        } else if (obj instanceof Long) {
            editor.putLong(key, (Long) obj);
        } else {
            editor.putString(key, obj.toString());
        }
        SharedPreferencesCompat.apply(editor);
    }


    /**
     * 获取保存数据的方法，我们根据默认值的到保存的数据的具体类型，然后调用相对于的方法获取值
     *
     * @param key
     * @param defaultObject
     * @return
     */
    public static Object get(String key, Object defaultObject) {
        SharedPreferences sharedPreferences = app.getSharedPreferences(Constant.APP_ID, Context.MODE_PRIVATE);
        if (defaultObject instanceof String) {
            return sharedPreferences.getString(key, (String) defaultObject);
        } else if (defaultObject instanceof Integer) {
            return sharedPreferences.getInt(key, (Integer) defaultObject);
        } else if (defaultObject instanceof Boolean) {
            return sharedPreferences.getBoolean(key, (Boolean) defaultObject);
        } else if (defaultObject instanceof Float) {
            return sharedPreferences.getFloat(key, (Float) defaultObject);
        } else if (defaultObject instanceof Long) {
            return sharedPreferences.getLong(key, (Long) defaultObject);
        } else {
            return sharedPreferences.getString(key, null);
        }
    }


    /**
     * 移除某个key值已经对应的值
     *
     * @param key
     */
    public static void remove(Context context, String key) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(Constant.APP_ID, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.remove(key);
        SharedPreferencesCompat.apply(editor);
    }

    /**
     * 清除所有的数据
     */
    public static void clear(Context context) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(Constant.APP_ID, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear();
        SharedPreferencesCompat.apply(editor);
    }

    /**
     * 查询某个key是否存在
     *
     * @param key
     * @return
     */
    public static boolean contains(Context context, String key) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(Constant.APP_ID, Context.MODE_PRIVATE);
        return sharedPreferences.contains(key);
    }

    /**
     * 返回所有的键值对
     *
     * @return
     */
    public static Map getAll(Context context) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(Constant.APP_ID, Context.MODE_PRIVATE);
        return sharedPreferences.getAll();
    }


    private static class SharedPreferencesCompat {
        private static final Method sApplyMethod = findApplyMethod();

        /**
         * 反射查找apply的方法
         *
         * @return
         */
        @SuppressWarnings({"unchecked", "rawtypes"})
        private static Method findApplyMethod() {
            try {
                Class clz = SharedPreferences.Editor.class;
                return clz.getMethod("apply");
            } catch (NoSuchMethodException e) {
            }

            return null;
        }

        /**
         * 如果找到则使用apply执行，否则使用commit
         *
         * @param editor
         */
        public static void apply(SharedPreferences.Editor editor) {
            try {
                if (sApplyMethod != null) {
                    sApplyMethod.invoke(editor);
                    return;
                }
            } catch (IllegalArgumentException e) {
            } catch (IllegalAccessException e) {
            } catch (InvocationTargetException e) {
            }
            editor.commit();
        }
    }
}