{"id":269,"date":"2025-06-03T10:48:42","date_gmt":"2025-06-05T03:17:42","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=269"},"modified":"2025-06-05T10:48:42","modified_gmt":"2025-06-05T03:17:42","slug":"swift-defer-scope-%e7%b5%90%e6%9d%9f%e6%99%82%e5%9f%b7%e8%a1%8c-func%e7%b5%90%e6%9d%9f%e5%9f%b7%e8%a1%8c","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/steven\/swift\/swift-defer-scope-%e7%b5%90%e6%9d%9f%e6%99%82%e5%9f%b7%e8%a1%8c-func%e7%b5%90%e6%9d%9f%e5%9f%b7%e8%a1%8c\/","title":{"rendered":"Swift \u7a0b\u5f0f\u6559\u5b78\uff1a\u6df1\u5165\u7406\u89e3 Defer \u4f5c\u7528\u57df\u7d50\u675f\u6642\u7684\u57f7\u884c\u884c\u70ba\uff082025 \u6700\u65b0\u8a9e\u6cd5\u8207\u6700\u4f73\u5be6\u8e10\uff09"},"content":{"rendered":"<h2>\u7c21\u4ecb<\/h2>\n<p>\u5728 Swift \u4e2d\uff0c`defer` \u662f\u4e00\u500b\u975e\u5e38\u6709\u7528\u7684\u8a9e\u6cd5\uff0c\u53ef\u4ee5\u78ba\u4fdd\u5728\u51fd\u6578\u7d50\u675f\u6216\u4f5c\u7528\u57df\u7d50\u675f\u6642\u57f7\u884c\u67d0\u4e9b\u4ee3\u78bc\u3002\u7121\u8ad6\u51fd\u6578\u662f\u5f9e\u54ea\u500b\u5206\u652f\u8fd4\u56de\uff0c\u6216\u662f\u6bcf\u500b `for` \u5faa\u74b0\u7684\u6bcf\u500b\u7d22\u5f15\u7d50\u675f\u524d\uff0c`defer` \u90fd\u6703\u88ab\u57f7\u884c\u3002\u9019\u4f7f\u5f97 `defer` \u5728\u8cc7\u6e90\u7ba1\u7406\u3001\u6e05\u7406\u64cd\u4f5c\u7b49\u5834\u666f\u4e2d\u975e\u5e38\u9069\u7528\u3002<\/p>\n<h2>\u5982\u4f55\u4f7f\u7528 Defer<\/h2>\n<p>`defer` \u8a9e\u53e5\u53ef\u4ee5\u653e\u7f6e\u5728\u4efb\u4f55\u6709\u82b1\u62ec\u865f `{}` \u7684\u4f5c\u7528\u57df\u4e2d\u3002\u9019\u610f\u5473\u8457\u4f60\u53ef\u4ee5\u5728\u51fd\u6578\u3001\u689d\u4ef6\u8a9e\u53e5\u3001\u5faa\u74b0\u7b49\u4e2d\u4f7f\u7528 `defer`\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u4f8b\u5b50\uff0c\u5c55\u793a\u5982\u4f55\u5728 `viewDidLoad` \u4e2d\u4f7f\u7528 `defer`\u3002<\/p>\n<pre><code class=\"language-swift line-numbers\">override func viewDidLoad() {\n    super.viewDidLoad()\n    deferTest()\n}\n<\/code><\/pre>\n<h2>\u4f7f\u7528 For \u5faa\u74b0\u8207 Defer<\/h2>\n<p>\u5728 `for` \u5faa\u74b0\u4e2d\uff0c\u6bcf\u500b\u7d22\u5f15\u7d50\u675f\u6642\u90fd\u6703\u57f7\u884c `defer` \u8a9e\u53e5\u3002\u4e0b\u9762\u7684\u7bc4\u4f8b\u5c55\u793a\u4e86\u9019\u4e00\u9ede\uff1a<\/p>\n<pre><code class=\"language-swift line-numbers\">func deferTest() {\n    for i in 0...10 {\n        defer {\n            print(\"\u7d50\u675f\")\n        }\n        print(\"\u57f7\u884c \\(i)\")\n    }\n}\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u793a\u4f8b\u4e2d\uff0c\u7576\u5faa\u74b0\u7d50\u675f\u6642\uff0c`defer` \u6703\u88ab\u57f7\u884c\uff0c\u7121\u8ad6\u5faa\u74b0\u7684\u7d42\u6b62\u689d\u4ef6\u5982\u4f55\u3002<\/p>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2020\/09\/wp_editor_md_15850c29ba5ab6ecf328b8113ce9587d.jpg\"><img decoding=\"async\" src=\"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2020\/09\/wp_editor_md_15850c29ba5ab6ecf328b8113ce9587d.jpg\" alt=\"\u793a\u7bc4 defer \u5728 for \u5faa\u74b0\u4e2d\u7684\u4f7f\u7528\" title=\"\"><\/a><\/p>\n<h2>\u666e\u901a\u51fd\u6578\u4e2d\u7684 Defer<\/h2>\n<p>\u5728\u666e\u901a\u51fd\u6578\u4e2d\uff0c`defer` \u6703\u5728\u51fd\u6578\u7684\u6700\u5f8c\u57f7\u884c\u3002\u4ee5\u4e0b\u662f\u7bc4\u4f8b\uff1a<\/p>\n<pre><code class=\"language-swift line-numbers\">func deferTest() {\n    defer {\n        print(\"\u7d50\u675f\")\n    }\n    print(\"\u57f7\u884c\")\n}\n<\/code><\/pre>\n<p>\u9019\u6bb5\u4ee3\u78bc\u5c55\u793a\u4e86\u5373\u4f7f\u5728\u51fd\u6578\u4e2d\u57f7\u884c\u5176\u4ed6\u4ee3\u78bc\uff0c`defer` \u4e5f\u6703\u5728\u51fd\u6578\u7684\u7d50\u5c3e\u88ab\u57f7\u884c\u3002<\/p>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2020\/09\/wp_editor_md_194b36370a1d95a2e3b4f75346636304.jpg\"><img decoding=\"async\" src=\"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2020\/09\/wp_editor_md_194b36370a1d95a2e3b4f75346636304.jpg\" alt=\"\u793a\u7bc4 defer \u5728\u666e\u901a\u51fd\u6578\u4e2d\u7684\u4f7f\u7528\" title=\"\"><\/a><\/p>\n<h2>Defer \u57f7\u884c\u9806\u5e8f<\/h2>\n<p>`defer` \u7684\u57f7\u884c\u9806\u5e8f\u662f\u5f9e\u6700\u5f8c\u4e00\u500b\u5230\u7b2c\u4e00\u500b\uff0c\u4e5f\u5c31\u662f\u8aaa\uff0c\u5f8c\u9762\u5b9a\u7fa9\u7684 `defer` \u6703\u5148\u57f7\u884c\u3002\u9019\u5728\u9700\u8981\u78ba\u4fdd\u7279\u5b9a\u9806\u5e8f\u7684\u6e05\u7406\u5de5\u4f5c\u6642\u975e\u5e38\u6709\u7528\u3002<\/p>\n<pre><code class=\"language-swift line-numbers\">func deferTest() {\n    print(\"1\")\n    defer {\n        print(\"6\")\n    }\n    print(\"2\")\n    defer {\n        print(\"5\")\n    }\n    print(\"3\")\n    defer {\n        print(\"4\")\n    }\n}\n<\/code><\/pre>\n<p>\u9019\u500b\u4f8b\u5b50\u5c07\u986f\u793a\u57f7\u884c\u7684\u9806\u5e8f\uff0c\u5e6b\u52a9\u4f60\u7406\u89e3\u5982\u4f55\u5229\u7528 `defer` \u4f86\u63a7\u5236\u4ee3\u78bc\u7684\u57f7\u884c\u6d41\u3002<\/p>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2020\/09\/wp_editor_md_4e1475349902ab14b881f13ca62ea1c7.jpg\"><img decoding=\"async\" src=\"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2020\/09\/wp_editor_md_4e1475349902ab14b881f13ca62ea1c7.jpg\" alt=\"\u793a\u7bc4 defer \u57f7\u884c\u9806\u5e8f\u7684\u7bc4\u4f8b\" title=\"\"><\/a><\/p>\n<h2>\u5e38\u898b\u932f\u8aa4\u6392\u9664<\/h2>\n<p>1. **\u932f\u8aa4\u4f7f\u7528 `defer` \u7684\u4f4d\u7f6e**\uff1a\u78ba\u4fdd `defer` \u4f4d\u65bc\u9069\u7576\u7684\u4f5c\u7528\u57df\u5167\uff0c\u5426\u5247\u53ef\u80fd\u4e0d\u6703\u5982\u9810\u671f\u57f7\u884c\u3002<br \/>\n2. **\u591a\u500b `defer` \u7684\u9806\u5e8f**\uff1a\u8a18\u4f4f `defer` \u7684\u57f7\u884c\u9806\u5e8f\u662f\u5f8c\u9032\u5148\u51fa\uff08LIFO\uff09\uff0c\u9019\u6709\u52a9\u65bc\u78ba\u4fdd\u6e05\u7406\u64cd\u4f5c\u6309\u7167\u6b63\u78ba\u7684\u9806\u5e8f\u57f7\u884c\u3002<\/p>\n<h2>\u5ef6\u4f38\u61c9\u7528<\/h2>\n<p>`defer` \u9664\u4e86\u5728\u51fd\u6578\u4e2d\u4f7f\u7528\u5916\uff0c\u9084\u53ef\u4ee5\u61c9\u7528\u65bc\u7570\u6b65\u64cd\u4f5c\u3001\u6587\u4ef6\u64cd\u4f5c\u7b49\u5834\u666f\u4e2d\uff0c\u78ba\u4fdd\u5728\u64cd\u4f5c\u7d50\u675f\u6642\u91cb\u653e\u8cc7\u6e90\u6216\u57f7\u884c\u5fc5\u8981\u7684\u6e05\u7406\u5de5\u4f5c\u3002<\/p>\n<h2>Q&#038;A\uff08\u5e38\u898b\u554f\u984c\u89e3\u7b54\uff09<\/h2>\n<p>**Q1\uff1a`defer` \u53ef\u4ee5\u5728\u4ec0\u9ebc\u5730\u65b9\u4f7f\u7528\uff1f**<br \/>\nA1\uff1a`defer` \u53ef\u7528\u65bc\u4efb\u4f55\u6709 `{}` \u7684\u4f5c\u7528\u57df\uff0c\u5305\u62ec\u51fd\u6578\u3001\u689d\u4ef6\u8a9e\u53e5\u548c\u5faa\u74b0\u7b49\u3002<\/p>\n<p>**Q2\uff1a`defer` \u7684\u57f7\u884c\u9806\u5e8f\u662f\u4ec0\u9ebc\uff1f**<br \/>\nA2\uff1a`defer` \u8a9e\u53e5\u7684\u57f7\u884c\u9806\u5e8f\u662f\u5f8c\u9032\u5148\u51fa\uff08LIFO\uff09\uff0c\u5373\u6700\u5f8c\u5b9a\u7fa9\u7684 `defer` \u6700\u5148\u57f7\u884c\u3002<\/p>\n<p>**Q3\uff1a\u4f7f\u7528 `defer` \u7684\u6700\u4f73\u5be6\u8e10\u662f\u4ec0\u9ebc\uff1f**<br \/>\nA3\uff1a\u5728\u9700\u8981\u78ba\u4fdd\u4ee3\u78bc\u5728\u4f5c\u7528\u57df\u7d50\u675f\u6642\u57f7\u884c\u7684\u60c5\u6cc1\u4e0b\u4f7f\u7528 `defer`\uff0c\u7279\u5225\u662f\u5728\u8cc7\u6e90\u7ba1\u7406\u548c\u932f\u8aa4\u8655\u7406\u6642\u3002<\/p>\n<p>&#8212;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>defer\u5c31\u662f return\/block \u4e4b\u524d\u57f7\u884c\uff0c\u7121\u8ad6\u51fd\u6578\u662f\u5f9e\u54ea\u500b\u5206\u652f return \u7684\uff0c\u6216\u662f\u55ae\u4e00\u500bfor\u6bcf\u500bindex \u7d50\u675f\u524d\u90fd\u6703\u57f7\u884c\u4e00\u6b21<br \/>\n\u4efb\u610f scope \u90fd\u53ef\u4ee5\u6709 defer<br \/>\n\u53ea\u8981\u6709{ }\u5c31\u53ef\u4ee5\u585e<\/p>\n","protected":false},"author":1,"featured_media":559,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"aside","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[5],"tags":[66,63,67,68],"class_list":["post-269","post","type-post","status-publish","format-aside","has-post-thumbnail","hentry","category-swift","tag-defer","tag-for","tag-scope","tag-68","post_format-post-format-aside"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2020\/11\/cup-1-1.png","jetpack-related-posts":[],"jetpack_shortlink":"https:\/\/wp.me\/pcFK27-4l","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/269","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/comments?post=269"}],"version-history":[{"count":4,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/269\/revisions"}],"predecessor-version":[{"id":1004,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/269\/revisions\/1004"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media\/559"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=269"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=269"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}