{"id":564,"date":"2023-02-09T22:42:05","date_gmt":"2023-02-09T14:42:05","guid":{"rendered":"https:\/\/iichen.cn\/?p=564"},"modified":"2023-02-09T22:42:05","modified_gmt":"2023-02-09T14:42:05","slug":"flutter-2","status":"publish","type":"post","link":"https:\/\/iichen.cn\/?p=564","title":{"rendered":"Flutter-\u5f02\u6b65"},"content":{"rendered":"<h4>1. FutureBuilder<\/h4>\n<pre><code class=\"language-dart line-numbers\">Center(\n    child: FutureBuilder(\n      \/\/ initialData: \"\u52a0\u8f7d\u4e2d\",\n      \/\/ future: Future.delayed(Duration(seconds: 2), () =&gt; \"123\"),\n      future: Future.delayed(Duration(seconds: 2), () =&gt; throw \"\u7f51\u7edc\u9519\u8beferror\"),\n      builder: (BuildContext context, AsyncSnapshot&lt;dynamic&gt; snapshot){\n        \/\/ snapshot.connectionState\n        if(snapshot.hasError) {\n          return Text(\"${snapshot.error}\");\n        }\n        \/\/ initialData\n        if(snapshot.hasData) {\n          return Text(\"\u6570\u636e ${snapshot.data}\");\n        }\n        return CircularProgressIndicator();\n      },\n    ),\n  ),\n);\n<\/code><\/pre>\n<h4>2. StreamBuild\uff08StreamController\uff09<\/h4>\n<blockquote><p>\n  \u9ed8\u8ba4\uff1a \u5355\u6b21\u76d1\u542c \uff08\u65e0\u76d1\u542c\u65f6 \u4f1a\u7f13\u5b58\u4e8b\u4ef6\uff09<br \/>\n  \u591a\u76d1\u542c\uff1a StreamController.broadcast(); \uff08\u65e0\u76d1\u542c\u65f6 \u4e0d\u4f1a\u7f13\u5b58\u4e8b\u4ef6\uff09\n<\/p><\/blockquote>\n<p><strong>\u5176\u4ed6Stream\u6784\u5efa\u65b9\u5f0f<\/strong><\/p>\n<pre><code class=\"language-dart line-numbers\">Stream&lt;DateTime&gt; getDate() async*{\n    while(true) {\n        await Future.delayed(Duration(seconds: 1));\n        yield DateTime.now();\n    }\n}\n<\/code><\/pre>\n<pre><code class=\"language-dart line-numbers\">StreamController _streamController = StreamController();\n\/\/ StreamController _streamController = StreamController.broadcast();\nint index = 0;\n\n@override\nWidget build(BuildContext context) {\n    return Scaffold(\n      appBar: AppBar(\n        title: Text('Test'),\n      ),\n      body: Center(\n        child: StreamBuilder(\n          stream: _streamController.stream,\n          builder: (BuildContext context, AsyncSnapshot&lt;dynamic&gt; snapshot){\n            \/\/ snapshot.connectionState\n            if(snapshot.hasError) {\n              return Text(\"${snapshot.error}\");\n            }\n            \/\/ initialData\n            if(snapshot.hasData) {\n              return Text(\"\u6570\u636e ${snapshot.data}\");\n            }\n            return CircularProgressIndicator();\n          },\n        ),\n      ),\n      floatingActionButton: FloatingActionButton(\n        onPressed: () {\n          _streamController.sink.add(\"event ${index++}\");\n        },\n      ),\n    );\n}\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>1. FutureBuilder Center( child: FutureBuilder( \/\/ initi [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,8],"tags":[],"class_list":["post-564","post","type-post","status-publish","format-standard","hentry","category-flutter","category-8"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v24.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Flutter-\u5f02\u6b65 - IIchen<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/iichen.cn\/?p=564\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Flutter-\u5f02\u6b65 - IIchen\" \/>\n<meta property=\"og:description\" content=\"1. 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