“`” \u7b54\u6848\uff1a<\/p>\n
<strong>kvc<\/strong>:<\/p>\n
\u952e\u503c\u7f16\u7801\u662f\u4e00\u79cd\u95f4\u63a5\u8bbf\u95ee\u5bf9\u8c61\u7684\u5c5e\u6027\u4f7f\u7528\u5b57\u7b26\u4e32\u6765\u6807\u8bc6\u5c5e\u6027\uff0c\u800c\u4e0d\u662f\u901a\u8fc7\u8c03\u7528\u5b58\u53d6\u65b9\u6cd5\uff0c\u76f4\u63a5\u6216\u901a\u8fc7\u5b9e\u4f8b\u53d8\u91cf\u8bbf\u95ee\u7684\u673a\u5236\u3002\u5f88\u591a\u60c5\u51b5\u4e0b\u53ef\u4ee5\u7b80\u5316\u7a0b\u5e8f\u4ee3\u7801\u3002apple\u6587\u6863\u5176\u5b9e\u7ed9\u4e86\u4e00\u4e2a\u5f88\u597d\u7684\u4f8b\u5b50\u3002
\n<strong>kvo<\/strong>:<\/p>\n
\u952e\u503c\u89c2\u5bdf\u673a\u5236\uff0c\u4ed6\u63d0\u4f9b\u4e86\u89c2\u5bdf\u67d0\u4e00\u5c5e\u6027\u53d8\u5316\u7684\u65b9\u6cd5\uff0c\u6781\u5927\u7684\u7b80\u5316\u4e86\u4ee3\u7801\u3002 \u5177\u4f53\u7528\u770b\u5230\u55ef\u54fc\u7528\u5230\u8fc7\u7684\u4e00\u4e2a\u5730\u65b9\u662f\u5bf9\u4e8e\u6309\u94ae\u70b9\u51fb\u53d8\u5316\u72b6\u6001\u7684\u7684\u76d1\u63a7\u3002 \u6bd4\u5982\u6211\u81ea\u5b9a\u4e49\u7684\u4e00\u4e2abutton<\/p>\n
<pre><code class=""language-objective-c"" lang=""objective-c""> [cpp]
\n [self addObserver:self forKeyPath:@""highlighted"" options:0 context:nil];
\n \\#pragma mark KVO
\n \\- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
\n {
\n if ([keyPath isEqualToString:@""highlighted""] ) {
\n [self setNeedsDisplay];
\n }
\n }
\n<\/code><\/pre><\/p>\n
\u5bf9\u4e8e\u7cfb\u7edf\u662f\u6839\u636ekeypath\u53bb\u53d6\u7684\u5230\u76f8\u5e94\u7684\u503c\u53d1\u751f\u6539\u53d8\uff0c\u7406\u8bba\u4e0a\u6765\u8bf4\u662f\u548ckvc\u673a\u5236\u7684\u9053\u7406\u662f\u4e00\u6837\u7684\u3002<\/p>\n
\u5bf9\u4e8ekvc\u673a\u5236\u5982\u4f55\u901a\u8fc7key\u5bfb\u627e\u5230value\uff1a
\n \u201c\u5f53\u901a\u8fc7KVC\u8c03\u7528\u5bf9\u8c61\u65f6\uff0c\u6bd4\u5982\uff1a[self valueForKey:@\u201dsomeKey\u201d]\u65f6\uff0c\u7a0b\u5e8f\u4f1a\u81ea\u52a8\u8bd5\u56fe\u901a\u8fc7\u51e0\u79cd\u4e0d\u540c\u7684\u65b9\u5f0f\u89e3\u6790\u8fd9\u4e2a\u8c03\u7528\u3002\u9996\u5148\u67e5\u627e\u5bf9\u8c61\u662f\u5426\u5e26\u6709 someKey \u8fd9\u4e2a\u65b9\u6cd5\uff0c\u5982\u679c\u6ca1\u627e\u5230\uff0c\u4f1a\u7ee7\u7eed\u67e5\u627e\u5bf9\u8c61\u662f\u5426\u5e26\u6709someKey\u8fd9\u4e2a\u5b9e\u4f8b\u53d8\u91cf\uff08iVar\uff09\uff0c\u5982\u679c\u8fd8\u6ca1\u6709\u627e\u5230\uff0c\u7a0b\u5e8f\u4f1a\u7ee7\u7eed\u8bd5\u56fe\u8c03\u7528 -(id) valueForUndefinedKey:\u8fd9\u4e2a\u65b9\u6cd5\u3002\u5982\u679c\u8fd9\u4e2a\u65b9\u6cd5\u8fd8\u662f\u6ca1\u6709\u88ab\u5b9e\u73b0\u7684\u8bdd\uff0c\u7a0b\u5e8f\u4f1a\u629b\u51fa\u4e00\u4e2aNSUndefinedKeyException\u5f02\u5e38\u9519\u8bef\u3002<\/p>\n
(cocoachina.com\u6ce8\uff1aKey-Value Coding\u67e5\u627e\u65b9\u6cd5\u7684\u65f6\u5019\uff0c\u4e0d\u4ec5\u4ec5\u4f1a\u67e5\u627esomeKey\u8fd9\u4e2a\u65b9\u6cd5\uff0c\u8fd8\u4f1a\u67e5\u627egetsomeKey\u8fd9\u4e2a\u65b9\u6cd5\uff0c\u524d\u9762\u52a0\u4e00\u4e2aget\uff0c\u6216\u8005<em>someKey\u4ee5\u53ca<\/em>getsomeKey\u8fd9\u51e0\u79cd\u5f62\u5f0f\u3002\u540c\u65f6\uff0c\u67e5\u627e\u5b9e\u4f8b\u53d8\u91cf\u7684\u65f6\u5019\u4e5f\u4f1a\u4e0d\u4ec5\u4ec5\u67e5\u627esomeKey\u8fd9\u4e2a\u53d8\u91cf\uff0c\u4e5f\u4f1a\u67e5\u627e_someKey\u8fd9\u4e2a\u53d8\u91cf\u662f\u5426\u5b58\u5728\u3002\uff09<\/p>\n
\u8bbe\u8ba1valueForUndefinedKey:\u65b9\u6cd5\u7684\u4e3b\u8981\u76ee\u7684\u662f\u5f53\u4f60\u4f7f\u7528-(id)valueForKey\u65b9\u6cd5\u4ece\u5bf9\u8c61\u4e2d\u8bf7\u6c42\u503c\u65f6\uff0c\u5bf9\u8c61\u80fd\u591f\u5728\u9519\u8bef\u53d1\u751f\u524d\uff0c\u6709\u6700\u540e\u7684\u673a\u4f1a\u54cd\u5e94\u8fd9\u4e2a\u8bf7\u6c42\u3002\u8fd9\u6837\u505a\u6709\u5f88\u591a\u597d\u5904\uff0c\u4e0b\u9762\u7684\u4e24\u4e2a\u4f8b\u5b50\u8bf4\u660e\u4e86\u8fd9\u6837\u505a\u7684\u597d\u5904\u3002\u201c
\n \u6765\u81f3cocoa\uff0c\u8fd9\u4e2a\u8bf4\u6cd5\u5e94\u8be5\u633a\u6709\u9053\u7406\u3002<\/p>\n
\u56e0\u4e3a\u6211\u4eec\u77e5\u9053button\u5374\u662f\u5b58\u5728\u4e00\u4e2ahighlighted\u5b9e\u4f8b\u53d8\u91cf.\u56e0\u6b64\u4e3a\u4f55\u4e0a\u9762\u6211\u4eec\u53ea\u662fadd\u4e00\u4e2a\u76f8\u5173\u7684keypath\u5c31\u884c\u4e86\uff0c <\/p>\n
<pre><code> "“`
\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
“`” \u7b54\u6848\uff1a <strong>kvc<\/strong>: \u952e […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-42501","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/42501","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=42501"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/42501\/revisions"}],"predecessor-version":[{"id":42502,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/42501\/revisions\/42502"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=42501"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=42501"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=42501"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}