{"id":7256,"date":"2022-09-05T10:29:01","date_gmt":"2022-09-05T02:29:01","guid":{"rendered":"http:\/\/123.57.164.21\/?p=7256"},"modified":"2022-09-05T10:29:01","modified_gmt":"2022-09-05T02:29:01","slug":"ios-selector","status":"publish","type":"post","link":"https:\/\/92it.top\/?p=7256","title":{"rendered":"iOS Selector"},"content":{"rendered":"\n<p><code>@selector<\/code> \u662f Objective-C \u65f6\u4ee3\u7684\u4e00\u4e2a\u5173\u952e\u5b57\uff0c\u5b83\u53ef\u4ee5\u5c06\u4e00\u4e2a\u65b9\u6cd5\u8f6c\u6362\u5e76\u8d4b\u503c\u7ed9\u4e00\u4e2a <code>SEL<\/code> \u7c7b\u578b\uff0c\u5b83\u7684\u8868\u73b0\u5f88\u7c7b\u4f3c\u4e00\u4e2a\u52a8\u6001\u7684\u51fd\u6570\u6307\u9488\u3002\u5728 Objective-C \u65f6 selector \u975e\u5e38\u5e38\u7528\uff0c\u4ece\u8bbe\u5b9a target-action\uff0c\u5230\u81ea\u4e3e\u8be2\u95ee\u662f\u5426\u54cd\u5e94\u67d0\u4e2a\u65b9\u6cd5\uff0c\u518d\u5230\u6307\u5b9a\u63a5\u53d7\u901a\u77e5\u65f6\u9700\u8981\u8c03\u7528\u7684\u65b9\u6cd5\u7b49\u7b49\uff0c\u90fd\u662f\u7531 selector \u6765\u8d1f\u8d23\u7684\u3002\u5728 Objective-C \u91cc\u751f\u6210\u4e00\u4e2a selector \u7684\u65b9\u6cd5\u4e00\u822c\u662f\u8fd9\u4e2a\u6837\u5b50\u7684\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">-(void) callMe {\n    \/\/...\n}\n\n-(void) callMeWithParam:(id)obj {\n    \/\/...\n}\n\nSEL someMethod = @selector(callMe);\nSEL anotherMethod = @selector(callMeWithParam:);\n\n\/\/ \u6216\u8005\u4e5f\u53ef\u4ee5\u4f7f\u7528 NSSelectorFromString\n\/\/ SEL someMethod = NSSelectorFromString(@\"callMe\");\n\/\/ SEL anotherMethod = NSSelectorFromString(@\"callMeWithParam:\");\n<\/pre>\n\n\n\n<p>\u4e00\u822c\u4e3a\u4e86\u65b9\u4fbf\uff0c\u5f88\u591a\u4eba\u4f1a\u9009\u62e9\u4f7f\u7528 <code>@selector<\/code>\uff0c\u4f46\u662f\u5982\u679c\u8981\u8ffd\u6c42\u7075\u6d3b\u7684\u8bdd\uff0c\u53ef\u80fd\u4f1a\u66f4\u613f\u610f\u4f7f\u7528 <code>NSSelectorFromString<\/code> \u7684\u7248\u672c &#8212; \u56e0\u4e3a\u6211\u4eec\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u52a8\u6001\u751f\u6210\u5b57\u7b26\u4e32\uff0c\u4ece\u800c\u901a\u8fc7\u65b9\u6cd5\u7684\u540d\u5b57\u6765\u8c03\u7528\u5230\u5bf9\u5e94\u7684\u65b9\u6cd5\u3002<\/p>\n\n\n\n<p>\u5728 Swift \u4e2d\u6ca1\u6709 <code>@selector<\/code> \u4e86\uff0c\u53d6\u800c\u4ee3\u4e4b\uff0c\u4ece Swift 2.2 \u5f00\u59cb\u6211\u4eec\u4f7f\u7528 <code>#selector<\/code> \u6765\u4ece\u66b4\u9732\u7ed9 Objective-C \u7684\u4ee3\u7801\u4e2d\u83b7\u53d6\u4e00\u4e2a selector\u3002\u7c7b\u4f3c\u5730\uff0c\u5728 Swift \u91cc\u5bf9\u5e94\u539f\u6765 <code>SEL<\/code> \u7684\u7c7b\u578b\u662f\u4e00\u4e2a\u53eb\u505a <code>Selector<\/code> \u7684\u7ed3\u6784\u4f53\u3002\u50cf\u4e0a\u9762\u7684\u4e24\u4e2a\u4f8b\u5b50\u5728 Swift \u4e2d\u7b49\u6548\u7684\u5199\u6cd5\u662f\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func callMe() {\n    \/\/...\n}\n\nfunc callMeWithParam(obj: AnyObject!) {\n    \/\/...\n}\n\nlet someMethod = #selector(callMe)\nlet anotherMethod = #selector(callMeWithParam(_:))<\/pre>\n\n\n\n<p>\u548c Objective-C \u65f6\u4e00\u6837\uff0c\u8bb0\u5f97\u5728 <code>callMeWithParam<\/code> \u540e\u9762\u52a0\u4e0a\u5192\u53f7 (:)\uff0c\u8fd9\u624d\u662f\u5b8c\u6574\u7684\u65b9\u6cd5\u540d\u5b57\u3002\u591a\u4e2a\u53c2\u6570\u7684\u65b9\u6cd5\u540d\u4e5f\u548c\u539f\u6765\u7c7b\u4f3c\uff0c\u662f\u8fd9\u4e2a\u6837\u5b50\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func turnByAngle(theAngle: Int, speed: Float) {\n    \/\/...\n}\n\nlet method = #selector(turnByAngle(_:speed:))\n<\/pre>\n\n\n\n<p>\u6700\u540e\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0cselector \u5176\u5b9e\u662f Objective-C runtime \u7684\u6982\u5ff5\uff0c\u5982\u679c\u4f60\u7684 selector \u5bf9\u5e94\u7684\u65b9\u6cd5\u53ea\u5728 Swift \u4e2d\u53ef\u89c1\u7684\u8bdd (\u4e5f\u5c31\u662f\u8bf4\u5b83\u662f\u4e00\u4e2a Swift \u4e2d\u7684 private \u65b9\u6cd5)\uff0c\u5728\u8c03\u7528\u8fd9\u4e2a selector \u65f6\u4f60\u4f1a\u9047\u5230\u4e00\u4e2a unrecognized selector \u9519\u8bef\uff1a<\/p>\n\n\n\n<p>\u8fd9\u662f\u9519\u8bef\u4ee3\u7801<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">private func callMe() {\n     \/\/...\n}\n\nNSTimer.scheduledTimerWithTimeInterval(1, target: self,\n            selector:#selector(callMe), userInfo: nil, repeats: true)<\/pre>\n\n\n\n<p>\u6b63\u786e\u7684\u505a\u6cd5\u662f\u5728 <code>private<\/code> \u524d\u9762\u52a0\u4e0a <code>@objc<\/code> \u5173\u952e\u5b57\uff0c\u8fd9\u6837\u8fd0\u884c\u65f6\u5c31\u80fd\u627e\u5230\u5bf9\u5e94\u7684\u65b9\u6cd5\u4e86\u3002<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">@objc private func callMe() {\n    \/\/...\n}\n\nNSTimer.scheduledTimerWithTimeInterval(1, target: self,\n             selector:#selector(callMe), userInfo: nil, repeats: true)<\/pre>\n\n\n\n<p>\u6700\u540e\uff0c\u503c\u5f97\u4e00\u63d0\u7684\u662f\uff0c\u5982\u679c\u65b9\u6cd5\u540d\u5b57\u5728\u65b9\u6cd5\u6240\u5728\u57df\u5185\u662f\u552f\u4e00\u7684\u8bdd\uff0c\u6211\u4eec\u53ef\u4ee5\u7b80\u5355\u5730\u53ea\u662f\u7528\u65b9\u6cd5\u7684\u540d\u5b57\u6765\u4f5c\u4e3a <code>#selector<\/code> \u7684\u5185\u5bb9\u3002\u76f8\u6bd4\u4e8e\u524d\u9762\u5e26\u6709\u5192\u53f7\u7684\u5b8c\u6574\u7684\u5f62\u5f0f\u6765\u8bf4\uff0c\u8fd9\u4e48\u5199\u8d77\u6765\u4f1a\u65b9\u4fbf\u4e00\u4e9b\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">let someMethod = #selector(callMe)\nlet anotherMethod = #selector(callMeWithParam)\nlet method = #selector(turnByAngle)\n<\/pre>\n\n\n\n<p>\u4f46\u662f\uff0c\u5982\u679c\u5728\u540c\u4e00\u4e2a\u4f5c\u7528\u57df\u4e2d\u5b58\u5728\u540c\u6837\u540d\u5b57\u7684\u4e24\u4e2a\u65b9\u6cd5\uff0c\u5373\u4f7f\u5b83\u4eec\u7684\u51fd\u6570\u7b7e\u540d\u4e0d\u76f8\u540c\uff0cSwift \u7f16\u8bd1\u5668\u4e5f\u4e0d\u5141\u8bb8\u7f16\u8bd1\u901a\u8fc7\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func commonFunc() {\n\n}\n\nfunc commonFunc(input: Int) -> Int {\n    return input\n}\n\nlet method = #selector(commonFunc)\n\/\/ \u7f16\u8bd1\u9519\u8bef\uff0c`commonFunc` \u6709\u6b67\u4e49<\/pre>\n\n\n\n<p>\u5bf9\u4e8e\u8fd9\u79cd\u95ee\u9898\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5c06\u65b9\u6cd5\u8fdb\u884c\u5f3a\u5236\u8f6c\u6362\u6765\u4f7f\u7528\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">let method1 = #selector(commonFunc as ()->())\nlet method2 = #selector(commonFunc as Int->Int)<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>@selector \u662f Objective-C \u65f6\u4ee3\u7684\u4e00\u4e2a\u5173\u952e\u5b57\uff0c\u5b83\u53ef\u4ee5\u5c06\u4e00\u4e2a\u65b9\u6cd5\u8f6c\u6362\u5e76\u8d4b\u503c\u7ed9\u4e00\u4e2a SEL \u7c7b [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,8],"tags":[],"_links":{"self":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/7256"}],"collection":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7256"}],"version-history":[{"count":1,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/7256\/revisions"}],"predecessor-version":[{"id":7257,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/7256\/revisions\/7257"}],"wp:attachment":[{"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7256"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7256"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7256"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}