{"id":254,"date":"2017-02-14T02:57:36","date_gmt":"2017-02-14T02:57:36","guid":{"rendered":"https:\/\/boochlin.com\/?p=254"},"modified":"2026-09-16T09:54:04","modified_gmt":"2026-09-16T09:54:04","slug":"android-issue-avoid-non-default-constructors-in-fragments","status":"publish","type":"post","link":"https:\/\/boochlin.com\/?p=254","title":{"rendered":"Android issue – Avoid non-default constructors in fragments"},"content":{"rendered":"

<\/h3>\n
\n\n\n\n\n\n\n\n
\u5e8f\u5217\u5316\u6a5f\u5236<\/th>\n1000 \u6b21\u5e8f\u5217\u5316\u5ef6\u9072 (ms)<\/th>\n1000 \u6b21\u53cd\u5e8f\u5217\u5316\u5ef6\u9072 (ms)<\/th>\n\u53cd\u5c04\u958b\u92b7<\/th>\n\u8a18\u61b6\u9ad4\u958b\u92b7<\/th>\n<\/tr>\n<\/thead>\n
**Parcelable**<\/td>\n**16.2 ms** (\u57fa\u6e96 1x)<\/td>\n**12.5 ms** (\u57fa\u6e96 1x)<\/td>\n\u7121 (\u76f4\u63a5\u8a18\u61b6\u9ad4\u584a\u8b80\u5beb)<\/td>\n\u6975\u4f4e<\/td>\n<\/tr>\n
**Serializable**<\/td>\n104.8 ms (\u6162 6.5x)<\/td>\n98.4 ms (\u6162 7.8x)<\/td>\n\u6975\u91cd (\u52d5\u614b\u578b\u5225\u53cd\u5c04)<\/td>\n\u9ad8<\/td>\n<\/tr>\n
**Gson \/ JSON**<\/td>\n382.1 ms (\u6162 23.5x)<\/td>\n415.6 ms (\u6162 33.2x)<\/td>\n\u91cd (\u5b57\u4e32\u89e3\u6790\u8207\u6620\u5c04)<\/td>\n\u6975\u9ad8<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\u672c\u7bc7\u91cd\u9ede<\/h3>\n
    \n
  1. \n

    \u6211\u9047\u5230\u4e86 non-default constructors in fragments: use a default constructor plus Fragment#setArguments(Bundle) instead\u3002<\/strong><\/p>\n<\/li>\n

  2. \n

    Parcelable \u5f88\u53b2\u5bb3\u3002<\/strong><\/p>\n<\/li>\n<\/ol>\n

    \u9019\u6b21\u958b\u767c side project \u7528\u5230\u5927\u91cf\u7684 fragment\u51fa\u65bc\u65b9\u4fbf\u7684\u60c5\u6cc1\u5c31\u4f7f\u7528\u5e95\u4e0b\u7684\u7528\u6cd5<\/p>\n

    public<\/span> class<\/span> MainPageTabFragment<\/span> extends<\/span> Fragment<\/span> {\n    String tab;\n    User user;\n    public<\/span> MainPageTabFragment<\/span>(String tab , User user)<\/span> {\n        this<\/span>.tab = tab;\n        this<\/span>.user = user;\n    }\n}\n\/\/ How to use<\/span>\nMainPageTabFragment<\/span> fragment<\/span> =<\/span> new<\/span> MainPageTabFragment<\/span>(tab, user);<\/code><\/pre>\n
    \u9019\u5728\u7528 debug build \u6642\u4e26\u6c92\u6709\u9047\u5230\u4efb\u4f55\u554f\u984c\uff0c\u4f46\u662f\u5230\u8981\u7528 release build \u6642\u537b\u51fa\u73fe\u4e86 \u201cAvoid non-default constructors in fragments: use a default constructor plus Fragment#setArguments(Bundle) instead\u201d \u9019\u6a23\u7684\u63d0\u793a\u932f\u8aa4\uff0c\u5c0e\u81f4 release build \u4e0d\u904e\uff0c\u4e3b\u56e0\u662f\u7531\u65bc lint check code \uff0c\u4e26\u540c\u6642\u5efa\u8b70\u4f7f\u7528 setArgument() \u4f86\u53d6\u4ee3\u4f7f\u7528\u542b\u6709\u53c3\u6578\u7684\u5efa\u69cb\u5b50\u3002<\/p>\n
    \u770b\u5230\u9019\u908a\u5982\u679c\u5c31\u53ea\u662f\u60f3\u55ae\u7d14\u89e3\u6c7a lint \u7684\u554f\u984c\uff0c\u90a3\u63d0\u4f9b\u6700\u7c21\u55ae\u7684\u65b9\u6cd5\uff5e\uff5e\uff5e\uff5e\uff5e\u90a3\u5c31\u4e0d\u8981\u6aa2\u67e5\u554a\uff0c\u53ea\u8981\u5728 build.gradle \u5167\u52a0\u5165\u5e95\u4e0b\u7684 code<\/p>\n
    android {\n          lintOptions {\n              checkReleaseBuilds false<\/span>\n          }\n      }<\/code><\/pre>\n
    \u6216\u662f\u5728 fragment \u52a0\u4e0a @SuppressLint(\u201cValidFragment\u201d)<\/p>\n
    ref:stackoverflow<\/a><\/p>\n
    \u5230\u9019\u88e1\uff0c\u5c31\u89e3\u6c7a\u4e86 lint \u5c0e\u81f4 release build \u7684\u554f\u984c\uff0c\u5ba2\u500c\u60f3\u5148\u4ea4\u5dee\u7d66\u8001\u95c6\u7684\u8a71\uff0c\u9019\u908a\u53ef\u4ee5\u6536\u5de5\u5566\uff0c\u5982\u679c\u9084\u6709\u8208\u8da3\u7684\u8a71\u5c31\u7e7c\u7e8c\u4f86\u7814\u7a76\u70ba\u4f55 lint \u4e0d\u5efa\u8b70\u9019\u6a23\u641e\u3002<\/p>\n
    \u4e3b\u8981\u539f\u56e0\u662f fragment \u7684\u7279\u6027<\/p>\n
    \u300eAll subclasses of Fragment must include a public no-argument constructor. The framework will often re-instantiate a fragment class when needed, in particular during state restore, and needs to be able to find this constructor to instantiate it. If the no-argument constructor is not available, a runtime exception will occur in some cases during state restore.\u300f<\/p>\n
    \u7d50\u8ad6\u5c31\u662f\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff08\u87a2\u5e55\u65b9\u5411\u8f49\u63db\uff09\uff0cfragment \u88ab\u7cfb\u7d71\u91cd\u5efa\u6642\uff0c\u53ea\u6703\u547c\u53eb\u7121\u53c3\u6578\u7684\u5efa\u69cb\u5b50\uff0c\u4f60\u7279\u5730\u7528\u6709\u53c3\u6578\u7684\u5efa\u69cb\u5b50\u5b58\u8d77\u4f86\u7684\u53c3\u6578\u4e0d\u6703\u88ab\u5b58\u8d77\u4f86\u3002\u770b\u5230\u9019\u908a\u5c31\u77e5\u9053\uff0c\u904e\u53bb\u7684\u7528\u6cd5\u591a\u5371\u96aa\uff08\u96d6\u7136\u6211\u9396\u5b9a\u87a2\u5e55\u65b9\u5411\u4e86\uff0c\u4f46\u9084\u662f\u5f88\u96e3\u4fdd\u8b49\u6709\u5565\u9b3c\u60c5\u6cc1\uff09\uff0c\u56e0\u6b64\u63a5\u4e0b\u4f86\u5c31\u4f86\u91cd\u69cb\u7a0b\u5f0f\u78bc<\/p>\n
    public<\/span> static<\/span> MainPageTabFragment<\/span> newInstance<\/span>(String tab, User user)<\/span> {\n        MainPageTabFragment<\/span> fragment<\/span> =<\/span> new<\/span> MainPageTabFragment<\/span>();\n        Bundle<\/span> argument<\/span> =<\/span> new<\/span> Bundle<\/span>();\n        argument.putString(MainPageTabFragment.KEY_TAB, tab);\n        argument.putParcelable(MainPageTabFragment.KEY_LOGIN_USER, user);\n        fragment.setArguments(argument);\n        return<\/span> fragment;\n    }\n\/\/ then get argument on onCreate() or onCreateView()<\/span>\npublic<\/span> View<\/span> onCreateView<\/span>(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)<\/span> {\n        Bundle<\/span> argument<\/span> =<\/span> getArguments();\n        this<\/span>.tab = argument.getString(KEY_TAB);\n        this<\/span>.loginUser = (User) argument.getParcelable(KEY_LOGIN_USER);\n}\n\/\/ How to use<\/span>\nMainPageTabFragment<\/span> fragment<\/span> =<\/span> MainPageTabFragment.newInstance(tab,user);<\/code><\/pre>\n
    \u770b\u5230\u9019\u908a\u767c\u73fe\u4e00\u4ef6\u7cdf\u7cd5\u7684\u4e8b\u60c5\uff0c\u5c31\u662f User \u4e26\u975e java \u57fa\u672c\u578b\u5225\uff0c\u6839\u672c\u7121\u6cd5\u653e\u9032 Bundle \u88e1\u9762\uff0c\u90a3\u5c31\u4e0d\u80fd setArgument()\uff0c\u7136\u5f8c\u6574\u5957\u91cd\u4f86\u3002<\/p>\n
    \u4e8b\u60c5\u7576\u7136\u6c92\u6709\u90a3\u9ebc\u56b4\u91cd\uff0c\u628a User \u5e8f\u5217\u5316\u5c31\u53ef\u4ee5\u4e86\uff0c\u5e8f\u5217\u5316\u7684\u65b9\u6cd5\u4e0d\u5c11\uff08\u81ea\u5df1\u5beb\u90fd\u53ef\u4ee5\uff09\uff0c\u4f46\u76ee\u524d\u6700\u4e3b\u6d41\u7684\u6709\u4e09\u7a2e<\/p>\n
      \n
    1. \n
      Serializable<\/p>\n<\/li>\n
    2. \n
      Parcelable<\/p>\n<\/li>\n
    3. \n
      Gson<\/p>\n<\/li>\n<\/ol>\n
      \u6b63\u7576\u982d\u75db\u8981\u7528\u54ea\u4e00\u5957\u6642\uff0c\u770b\u5230\u9019\u7bc7\u6587\u7ae0<\/a>\u9084\u6709\u9019\u5f35\u5716<\/p>\n
      \n\n\n\n\n\n\n\n
      \u5e8f\u5217\u5316\u6a5f\u5236<\/th>\n1000 \u6b21\u5e8f\u5217\u5316\u5ef6\u9072 (ms)<\/th>\n1000 \u6b21\u53cd\u5e8f\u5217\u5316\u5ef6\u9072 (ms)<\/th>\n\u53cd\u5c04\u958b\u92b7<\/th>\n\u8a18\u61b6\u9ad4\u958b\u92b7<\/th>\n<\/tr>\n<\/thead>\n
      **Parcelable**<\/td>\n**16.2 ms** (\u57fa\u6e96 1x)<\/td>\n**12.5 ms** (\u57fa\u6e96 1x)<\/td>\n\u7121 (\u76f4\u63a5\u8a18\u61b6\u9ad4\u584a\u8b80\u5beb)<\/td>\n\u6975\u4f4e<\/td>\n<\/tr>\n
      **Serializable**<\/td>\n104.8 ms (\u6162 6.5x)<\/td>\n98.4 ms (\u6162 7.8x)<\/td>\n\u6975\u91cd (\u52d5\u614b\u578b\u5225\u53cd\u5c04)<\/td>\n\u9ad8<\/td>\n<\/tr>\n
      **Gson \/ JSON**<\/td>\n382.1 ms (\u6162 23.5x)<\/td>\n415.6 ms (\u6162 33.2x)<\/td>\n\u91cd (\u5b57\u4e32\u89e3\u6790\u8207\u6620\u5c04)<\/td>\n\u6975\u9ad8<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
      Parcelable \u8d85\u7d1a\u5feb\uff0c\u5c31\u6c7a\u5b9a\u662f\u4f60\u4e86\u3002\uff08\u81f3\u65bc\u70ba\u4f55\u90a3\u9ebc\u5feb\uff0c\u53ef\u4ee5\u8a73\u7d30\u95b1\u8b80\u6587\u7ae0\uff0c\u4e3b\u8981\u662f gson and Serializable \u90fd\u6709\u9700\u8981\u578b\u5225\u6620\u5c04\u7684\u6642\u9593\uff09\u5b9a\u6848\u5f8c\u63a5\u8005\u5c31\u8981\u4f86\u5be6\u4f5c User \u7684 Parcelable interface\uff0c\u9019\u90e8\u5206\u4e3b\u8981\u6709\u5e7e\u500b\u6a21\u584a<\/p>\n
      \/\/ \u8b1b\u4e00\u4e0b\u505a\u5565<\/span>\n    @Override<\/span>\n    public<\/span> int<\/span> describeContents<\/span>()<\/span> {\n        return<\/span> 0<\/span>;\n    }\n    \/\/ \u5beb\u5165\u5bb9\u5668 parcel<\/span>\n    @Override<\/span>\n    public<\/span> void<\/span> writeToParcel<\/span>(Parcel dest, int<\/span> flags)<\/span> {\n        dest.writeValue(this<\/span>.id);\n        dest.writeString(this<\/span>.userName);\n        dest.writeString(this<\/span>.email);\n        dest.writeString(this<\/span>.userID);\n        dest.writeString(this<\/span>.userCode);\n        dest.writeString(this<\/span>.userIcon);\n    }\n    \/\/ \u50b3\u5165\u5bb9\u5668 parcel<\/span>\n    protected<\/span> User<\/span>(Parcel in)<\/span> {\n        this<\/span>.id = (Long) in.readValue(Long.class.getClassLoader());\n        this<\/span>.userName = in.readString();\n        this<\/span>.email = in.readString();\n        this<\/span>.userID = in.readString();\n        this<\/span>.userCode = in.readString();\n        this<\/span>.userIcon = in.readString();\n    }\n    \/\/ \u63d0\u4f9b\u9084\u539f\u65b9\u6cd5<\/span>\n    public<\/span> static<\/span> final<\/span> Parcelable.Creator<\/span> CREATOR<\/span> =<\/span> new<\/span> Parcelable<\/span>.Creator() {\n        @Override<\/span>\n        public<\/span> User<\/span> createFromParcel<\/span>(Parcel source)<\/span> {\n            return<\/span> new<\/span> User<\/span>(source);\n        }\n\n        @Override<\/span>\n        public<\/span> User<\/span>[] newArray<\/span>(int<\/span> size)<\/span> {\n            return<\/span> new<\/span> User<\/span>[size];\n        }\n    };<\/code><\/pre>\n
      \u6700\u5f8c\u63d0\u4e00\u4e0b\uff0c\u4e0a\u9762\u7684 Parcelable \u6839\u672c\u5c31\u662f dirty code \uff0c\u6240\u4ee5\u76f4\u89ba\u4e00\u5b9a\u6709\u81ea\u52d5\u5316\u5de5\u5177\uff0c\u6240\u4ee5\u5206\u4eabandroid parcelable code generator<\/a>\u00a0\u7d66\u5927\u5bb6\u3002<\/p>\n
      \u5feb\u6377\u9375\uff1aAlt + Insert (Windows\/Linux) \u6216 Cmd + N (macOS) \n-> \u9078\u64c7\u300cParcelable\u300d\n-> \u81ea\u52d5\u751f\u6210 describeContents()\u3001writeToParcel() \u8207 CREATOR \u6a21\u677f\u7a0b\u5f0f\u78bc\u3002<\/code><\/pre>\n
      \u4e00\u500b CLICK \u5c31\u5168\u90e8\u81ea\u52d5\u751f\u51fa CODE\uff0c\u611f\u8b1d\u5404\u4f4d\u770b\u5230\u9019\u88e1\u3002\u6253\u70ca\u5566<\/p>\n
      ref:<\/p>\n
      http:\/\/www.developerphil.com\/parcelable-vs-serializable\/<\/a><\/p>\n
      http:\/\/blog.csdn.net\/kroclin\/article\/details\/40902721<\/a><\/p>\n
      http:\/\/blog.prolificinteractive.com\/2014\/07\/18\/why-we-love-parcelable\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
      \u5e8f\u5217\u5316\u6a5f\u5236 1000 \u6b21\u5e8f\u5217\u5316\u5ef6\u9072 (ms) 1000 \u6b21\u53cd\u5e8f\u5217\u5316\u5ef6\u9072 (ms) \u53cd\u5c04\u958b\u92b7 \u8a18\u61b6\u9ad4\u958b\u92b7 **P […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[168],"tags":[223,293],"_links":{"self":[{"href":"https:\/\/boochlin.com\/index.php?rest_route=\/wp\/v2\/posts\/254"}],"collection":[{"href":"https:\/\/boochlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/boochlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/boochlin.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/boochlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=254"}],"version-history":[{"count":3,"href":"https:\/\/boochlin.com\/index.php?rest_route=\/wp\/v2\/posts\/254\/revisions"}],"predecessor-version":[{"id":1401,"href":"https:\/\/boochlin.com\/index.php?rest_route=\/wp\/v2\/posts\/254\/revisions\/1401"}],"wp:attachment":[{"href":"https:\/\/boochlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=254"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/boochlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=254"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/boochlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=254"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}