SharedPreferencesUtils（一個輕量級存儲工具類）

用途：存放标記性資料和設定資訊

功能：

1.儲存字元串：saveString

2.傳回字元串：getString

3.儲存布爾：saveBoolean

4.傳回布爾：getBoolean

5.儲存int：saveInt

6.傳回int：getInt

7.儲存float：saveFloat

8.傳回float：getFloat

9.查詢某個key是否已經存在：contains

public class SharedPreferencesUtils {

    public static final String SP_NAME = "config";
    private static SharedPreferences sp;

    /**
     * 儲存字元串
     *
     * @param context
     * @param key
     * @param value
     */
    public static void saveString(Context context, String key, String value) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }
        sp.edit().putString(key, value).commit();
    }

    /**
     * 傳回字元串
     *
     * @param context
     * @param key
     * @param defValue 預設值
     * @return
     */
    public static String getString(Context context, String key, String defValue) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }
        return sp.getString(key, defValue);
    }

    /**
     * 儲存布爾
     *
     * @param context
     * @param key
     * @param value
     */
    public static void saveBoolean(Context context, String key, boolean value) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }
        sp.edit().putBoolean(key, value).commit();
    }

    /**
     * 傳回布爾
     *
     * @param context
     * @param key
     * @param defValue 預設值
     * @return
     */
    public static boolean getBoolean(Context context, String key, boolean defValue) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }

        return sp.getBoolean(key, defValue);
    }

    /**
     * 儲存int
     *
     * @param context
     * @param key
     * @param value
     */
    public static void saveInt(Context context, String key, int value) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }

        sp.edit().putInt(key, value).commit();
    }
    /**
     * 傳回int
     *
     * @param context
     * @param key
     * @param defValue 預設值
     * @return
     */
    public static int getInt(Context context, String key, int defValue) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }

        return sp.getInt(key, defValue);
    }
    /**
     * 儲存float
     *
     * @param context
     * @param key
     * @param value
     */
    public static void saveFloat(Context context, String key, float value) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }

        sp.edit().putFloat(key, value).commit();
    }
    /**
     * 傳回float
     *
     * @param context
     * @param key
     * @param defValue 預設值
     * @return
     */
    public static float getFloat(Context context, String key, float defValue) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }

        return sp.getFloat(key, defValue);
    }

    /**
     * 查詢某個key是否已經存在
     *
     * @param context
     * @param key
     * @return
     */
    public static boolean contains(Context context, String key) {
        if (sp == null){
            sp = context.getSharedPreferences(SP_NAME, 0);
        }
        return sp.contains(key);
    }

}