“`”<\/p>\n
<h2>1 KVC(KeyValueCoding)<\/h2><\/p>\n
<h3>1.1 KVC \u5e38\u7528\u7684\u65b9\u6cd5<\/h3><\/p>\n
<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">(1)\u8d4b\u503c\u7c7b\u65b9\u6cd5
\n– (void)setValue:(nullable id)value forKey:(NSString *)key;
\n– (void)setValue:(nullable id)value forKeyPath:(NSString *)keyPath;
\n– (void)setValue:(nullable id)value forUndefinedKey:(NSString *)key;
\n– (void)setValuesForKeysWithDictionary:(NSDictionary<NSString *, id> *)keyedValues;<\/p>\n
(2)\u53d6\u503c\u7c7b\u65b9\u6cd5
\n\/\/ \u80fd\u53d6\u5f97\u79c1\u6709\u6210\u5458\u53d8\u91cf\u7684\u503c
\n– (id)valueForKey:(NSString *)key;
\n– (id)valueForKeyPath:(NSString *)keyPath;
\n– (NSDictionary *)dictionaryWithValuesForKeys:(NSArray *)keys;
\n<\/code><\/pre><\/p>\n
<h3>1.2 KVC \u5e95\u5c42\u5b9e\u73b0\u539f\u7406<\/h3><\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">\u5f53\u4e00\u4e2a\u5bf9\u8c61\u8c03\u7528setValue:forKey: \u65b9\u6cd5\u65f6,\u65b9\u6cd5\u5185\u90e8\u4f1a\u505a\u4ee5\u4e0b\u64cd\u4f5c:
\n 1.\u5224\u65ad\u6709\u6ca1\u6709\u6307\u5b9akey\u7684set\u65b9\u6cd5,\u5982\u679c\u6709set\u65b9\u6cd5,\u5c31\u4f1a\u8c03\u7528set\u65b9\u6cd5,\u7ed9\u8be5\u5c5e\u6027\u8d4b\u503c
\n 2.\u5982\u679c\u6ca1\u6709set\u65b9\u6cd5,\u5224\u65ad\u6709\u6ca1\u6709\u8ddfkey\u503c\u76f8\u540c\u4e14\u5e26\u6709\u4e0b\u5212\u7ebf\u7684\u6210\u5458\u5c5e\u6027(_key).\u5982\u679c\u6709,\u76f4\u63a5\u7ed9\u8be5\u6210\u5458\u5c5e\u6027\u8fdb\u884c\u8d4b\u503c
\n 3.\u5982\u679c\u6ca1\u6709\u6210\u5458\u5c5e\u6027_key,\u5224\u65ad\u6709\u6ca1\u6709\u8ddfkey\u76f8\u540c\u540d\u79f0\u7684\u5c5e\u6027.\u5982\u679c\u6709,\u76f4\u63a5\u7ed9\u8be5\u5c5e\u6027\u8fdb\u884c\u8d4b\u503c
\n 4.\u5982\u679c\u90fd\u6ca1\u6709,\u5c31\u4f1a\u8c03\u7528 valueforUndefinedKey \u548csetValue:forUndefinedKey:\u65b9\u6cd5
\n<\/code><\/pre><\/p>\n
<h3>1.3 KVC \u7684\u4f7f\u7528\u573a\u666f<\/h3><\/p>\n
<h4>1.3.1 \u8d4b\u503c<\/h4><\/p>\n
(1) KVC \u7b80\u5355\u5c5e\u6027\u8d4b\u503c<\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">Person *p = [[Person alloc] init];
\n\/\/ p.name = @""jack"";
\n\/\/ p.money = 22.2;
\n\u4f7f\u7528setValue: forKey:\u65b9\u6cd5\u80fd\u591f\u7ed9\u5c5e\u6027\u8d4b\u503c,\u7b49\u4ef7\u4e8e\u76f4\u63a5\u7ed9\u5c5e\u6027\u8d4b\u503c
\n[p setValue:@""rose"" forKey:@""name""];
\n[p setValue:@""22.2"" forKey:@""money""];
\n<\/code><\/pre><\/p>\n
(2) KVC\u590d\u6742\u5c5e\u6027\u8d4b\u503c<\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">\/\/\u7ed9Person\u6dfb\u52a0 Dog\u5c5e\u6027
\n Person *p = [[Person alloc] init];
\n p.dog = [[Dog alloc] init];
\n \/\/ p.dog.name = @""\u963f\u9ec4"";<\/p>\n
1)setValue: forKeyPath: \u65b9\u6cd5\u7684\u4f7f\u7528
\n \/\/\u4fee\u6539p.dog \u7684name \u5c5e\u6027
\n [p.dog setValue:@""wangcai"" forKeyPath:@""name""];
\n [p setValue:@""\u963f\u82b1"" forKeyPath:@""dog.name""];<\/p>\n
2)setValue: forKey: \u9519\u8bef\u7528\u6cd5
\n [p setValue:@""\u963f\u82b1"" forKey:@""dog.name""];
\n NSLog(@""%@"", p.dog.name);<\/p>\n
3)\u76f4\u63a5\u4fee\u6539\u79c1\u6709\u6210\u5458\u53d8\u91cf
\n[p setValue:@""\u65fa\u8d22"" forKeyPath:@""_name""];
\n<\/code><\/pre><\/p>\n
(3) \u6dfb\u52a0\u79c1\u6709\u6210\u5458\u53d8\u91cf<\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">Person \u7c7b\u4e2d\u6dfb\u52a0\u79c1\u6709\u6210\u5458\u53d8\u91cf_age
\n[p setValue:@""22"" forKeyPath:@""_age""];
\n<\/code><\/pre><\/p>\n
<h4>1.3.2 \u5b57\u5178\u8f6c\u6a21\u578b<\/h4><\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">(1)\u7b80\u5355\u7684\u5b57\u5178\u8f6c\u6a21\u578b
\n +(instancetype)videoWithDict:(NSDictionary *)dict
\n{
\n JLVideo *videItem = [[JLVideo alloc] init];
\n \/\/\u4ee5\u524d
\n\/\/ videItem.name = dict[@""name""];
\n\/\/ videItem.money = [dict[@""money""] doubleValue] ;<\/p>\n
\/\/KVC,\u4f7f\u7528setValuesForKeysWithDictionary:\u65b9\u6cd5,\u8be5\u65b9\u6cd5\u9ed8\u8ba4\u6839\u636e\u5b57\u5178\u4e2d\u6bcf\u4e2a\u952e\u503c\u5bf9,\u8c03\u7528setValue:forKey\u65b9\u6cd5
\n \/\/ \u7f3a\u70b9:\u5b57\u5178\u4e2d\u7684\u952e\u503c\u5bf9\u5fc5\u987b\u4e0e\u6a21\u578b\u4e2d\u7684\u952e\u503c\u5bf9\u5b8c\u5168\u5bf9\u5e94,\u5426\u5219\u7a0b\u5e8f\u4f1a\u5d29\u6e83
\n [videItem setValuesForKeysWithDictionary:dict];
\n return videItem;
\n}<\/p>\n
(2)\u590d\u6742\u7684\u5b57\u5178\u8f6c\u6a21\u578b
\n\u6ce8\u610f:\u590d\u6742\u5b57\u5178\u8f6c\u6a21\u578b\u4e0d\u80fd\u76f4\u63a5\u901a\u8fc7KVC \u8d4b\u503c,KVC\u53ea\u80fd\u5728\u7b80\u5355\u5b57\u5178\u4e2d\u4f7f\u7528,\u6bd4\u5982:
\n NSDictionary *dict = @{
\n @""name"" : @""jack"",
\n @""money"": @""22.2"",
\n @""dog"" : @{
\n @""name"" : @""wangcai"",
\n @""money"": @""11.1"",<\/p>\n
}<\/p>\n
};
\n JLPerson *p = [[JLPerson alloc]init]; \/\/ p\u662f\u4e00\u4e2a\u6a21\u578b\u5bf9\u8c61
\n [p setValuesForKeysWithDictionary:dict];
\n\u5185\u90e8\u8f6c\u6362\u539f\u7406:
\n\/\/ [p setValue:@""jack"" forKey:@""name""];
\n\/\/ [p setValue:@""22.2"" forKey:@""money""];
\n\/\/ [p setValue:@{
\n\/\/ @""name"" : @""wangcai"",
\n\/\/ @""money"": @""11.1"",
\n\/\/
\n\/\/ } forKey:@""dog""]; \/\/\u7ed9 dog\u8d4b\u503c\u4e00\u4e2a\u5b57\u5178\u80af\u5b9a\u662f\u4e0d\u5bf9\u7684<\/p>\n
(3)KVC\u89e3\u6790\u590d\u6742\u5b57\u5178\u7684\u6b63\u786e\u6b65\u9aa4
\n NSDictionary *dict = @{
\n @""name"" : @""jack"",
\n @""money"": @""22.2"",
\n @""dog"" : @{
\n @""name"" : @""wangcai"",
\n @""price"": @""11.1"",
\n },
\n \/\/\u4eba\u6709\u597d\u591a\u4e66
\n @""books"" : @[
\n @{
\n @""name"" : @""5\u5206\u949f\u7a81\u7834iOS\u5f00\u53d1"",
\n @""price"" : @""19.8""
\n },
\n @{
\n @""name"" : @""3\u5206\u949f\u7a81\u7834iOS\u5f00\u53d1"",
\n @""price"" : @""24.8""
\n },
\n @{
\n @""name"" : @""1\u5206\u949f\u7a81\u7834iOS\u5f00\u53d1"",
\n @""price"" : @""29.8""
\n }
\n ]
\n };<\/p>\n
XMGPerson *p = [[XMGPerson alloc] init];
\n p.dog = [[XMGDog alloc] init];
\n [p.dog setValuesForKeysWithDictionary:dict[@""dog""]];<\/p>\n
\/\/\u4fdd\u5b58\u6a21\u578b\u7684\u53ef\u53d8\u6570\u7ec4
\n NSMutableArray *arrayM = [NSMutableArray array];<\/p>\n
for (NSDictionary *dict in dict[@""books""]) {
\n \/\/\u521b\u5efa\u6a21\u578b
\n Book *book = [[Book alloc] init];
\n \/\/KVC
\n [book setValuesForKeysWithDictionary:dict];
\n \/\/\u5c06\u6a21\u578b\u4fdd\u5b58
\n [arrayM addObject:book];
\n }<\/p>\n
p.books = arrayM;<\/p>\n
\u5907\u6ce8:
\n (1)\u5f53\u5b57\u5178\u4e2d\u7684\u952e\u503c\u5bf9\u5f88\u590d\u6742,\u4e0d\u9002\u5408\u7528KVC;
\n (2)\u670d\u52a1\u5668\u8fd4\u8fd8\u7684\u6570\u636e,\u4f60\u53ef\u80fd\u4e0d\u4f1a\u5168\u7528\u4e0a,\u5982\u679c\u5728\u6a21\u578b\u4e00\u4e2a\u4e00\u4e2a\u5199\u5c5e\u6027\u975e\u5e38\u9ebb\u70e6,\u6240\u4ee5\u4e0d\u5efa\u8bae\u4f7f\u7528KVC\u5b57\u5178\u8f6c\u6a21\u578b
\n<\/code><\/pre><\/p>\n
<h4>1.3.3 \u53d6\u503c<\/h4><\/p>\n
(1) \u6a21\u578b\u8f6c\u5b57\u5178<\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc""> Person *p = [[Person alloc]init];
\n p.name = @""jack"";
\n p.money = 11.1;
\n \/\/KVC\u53d6\u503c
\n NSLog(@""%@ %@"", [p valueForKey:@""name""], [p valueForKey:@""money""]);<\/p>\n
\/\/\u6a21\u578b\u8f6c\u5b57\u5178, \u6839\u636e\u6570\u7ec4\u4e2d\u7684\u952e\u83b7\u53d6\u5230\u503c,\u7136\u540e\u653e\u5230\u5b57\u5178\u4e2d
\n NSDictionary *dict = [p dictionaryWithValuesForKeys:@[@""name"", @""money""]];
\n NSLog(@""%@"", dict);
\n<\/code><\/pre><\/p>\n
(2) \u8bbf\u95ee\u6570\u7ec4\u4e2d\u5143\u7d20\u7684\u5c5e\u6027\u503c<\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">Book *book1 = [[Book alloc] init];
\nbook1.name = @""5\u5206\u949f\u7a81\u7834iOS\u5f00\u53d1"";
\nbook1.price = 10.7;<\/p>\n
Book *book2 = [[Book alloc] init];
\nbook2.name = @""4\u5206\u949f\u7a81\u7834iOS\u5f00\u53d1"";
\nbook2.price = 109.7;<\/p>\n
Book *book3 = [[Book alloc] init];
\nbook3.name = @""1\u5206\u949f\u7a81\u7834iOS\u5f00\u53d1"";
\nbook3.price = 1580.7;<\/p>\n
\/\/ \u5982\u679cvalueForKeyPath:\u65b9\u6cd5\u7684\u8c03\u7528\u8005\u662f\u6570\u7ec4\uff0c\u90a3\u4e48\u5c31\u662f\u53bb\u8bbf\u95ee\u6570\u7ec4\u5143\u7d20\u7684\u5c5e\u6027\u503c
\n\/\/ \u53d6\u5f97books\u6570\u7ec4\u4e2d\u6240\u6709Book\u5bf9\u8c61\u7684name\u5c5e\u6027\u503c\uff0c\u653e\u5728\u4e00\u4e2a\u65b0\u7684\u6570\u7ec4\u4e2d\u8fd4\u56de
\n NSArray *books = @[book1, book2, book3];
\n NSArray *names = [books valueForKeyPath:@""name""];
\n NSLog(@""%@"", names);<\/p>\n
\/\/\u8bbf\u95ee\u5c5e\u6027\u6570\u7ec4\u4e2d\u5143\u7d20\u7684\u5c5e\u6027\u503c
\nPerson *p = [[Person alloc]init];
\np.books = @[book1, book2, book3];
\nNSArray *names = [p valueForKeyPath:@""books.name""];
\nNSLog(@""%@"", names);
\n<\/code><\/pre><\/p>\n
<h2>2 KVO (Key Value Observing)<\/h2><\/p>\n
<h3>2.1 KVO \u7684\u5e95\u5c42\u5b9e\u73b0\u539f\u7406<\/h3><\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">(1)KVO \u662f\u57fa\u4e8e runtime \u673a\u5236\u5b9e\u73b0\u7684
\n(2)\u5f53\u4e00\u4e2a\u5bf9\u8c61(\u5047\u8bbe\u662fperson\u5bf9\u8c61,\u5bf9\u5e94\u7684\u7c7b\u4e3a JLperson)\u7684\u5c5e\u6027\u503cage\u53d1\u751f\u6539\u53d8\u65f6,\u7cfb\u7edf\u4f1a\u81ea\u52a8\u751f\u6210\u4e00\u4e2a\u7ee7\u627f\u81eaJLperson\u7684\u7c7bNSKVONotifying_JLPerson,\u5728\u8fd9\u4e2a\u7c7b\u7684 setAge \u65b9\u6cd5\u91cc\u9762\u8c03\u7528
\n [super setAge:age];
\n [self willChangeValueForKey:@""age""];
\n [self didChangeValueForKey:@""age""];
\n \u4e09\u4e2a\u65b9\u6cd5,\u800c\u540e\u9762\u4e24\u4e2a\u65b9\u6cd5\u5185\u90e8\u4f1a\u4e3b\u52a8\u8c03\u7528
\n -(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context\u65b9\u6cd5,\u5728\u8be5\u65b9\u6cd5\u4e2d\u53ef\u4ee5\u62ff\u5230\u5c5e\u6027\u6539\u53d8\u524d\u540e\u7684\u503c.
\n<\/code><\/pre><\/p>\n
<h3>2.2 KVO\u7684\u4f5c\u7528<\/h3><\/p>\n
<ul>
\n<li>\u4f5c\u7528:\u80fd\u591f\u76d1\u542c\u67d0\u4e2a\u5bf9\u8c61\u5c5e\u6027\u503c\u7684\u6539\u53d8<\/li>
\n<\/ul><\/p>\n
\u00a0<\/p>\n
<pre><code class=""language-objc"" lang=""objc"">\/\/ \u5229\u7528KVO\u76d1\u542cp\u5bf9\u8c61name \u5c5e\u6027\u503c\u7684\u6539\u53d8
\n Person *p = [[XMGPerson alloc] init];
\n p.name = @""jack"";<\/p>\n
\/* \u5bf9\u8c61p\u6dfb\u52a0\u4e00\u4e2a\u89c2\u5bdf\u8005\uff08\u76d1\u542c\u5668\uff09
\n Observer\uff1a\u89c2\u5bdf\u8005\uff08\u76d1\u542c\u5668\uff09
\n KeyPath\uff1a\u5c5e\u6027\u540d\uff08\u9700\u8981\u76d1\u542c\u54ea\u4e2a\u5c5e\u6027\uff09
\n *\/
\n [p addObserver:self forKeyPath:@""name"" options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:@""123""];<\/p>\n
\/**
\n * \u5229\u7528KVO \u76d1\u542c\u5230\u5bf9\u8c61\u5c5e\u6027\u503c\u6539\u53d8\u540e,\u5c31\u4f1a\u8c03\u7528\u8fd9\u4e2a\u65b9\u6cd5
\n *
\n * @param keyPath \u54ea\u4e00\u4e2a\u5c5e\u6027\u88ab\u6539\u4e86
\n * @param object \u54ea\u4e00\u4e2a\u5bf9\u8c61\u7684\u5c5e\u6027\u88ab\u6539\u4e86
\n * @param change \u6539\u6210\u4ec0\u4e48\u6837\u4e86
\n *\/
\n– (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
\n{
\n \/\/ NSKeyValueChangeNewKey == @""new""
\n NSString *new = change[NSKeyValueChangeNewKey];
\n \/\/ NSKeyValueChangeOldKey == @""old""
\n NSString *old = change[NSKeyValueChangeOldKey];<\/p>\n
NSLog(@""%@-%@"",new,old);
\n}<\/p>\n
<\/code><\/pre><\/p>\n
<pre><code> "“`
\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
“`” <h2>1 KVC(KeyValueCoding)<\/h2& […]<\/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-42411","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/42411","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=42411"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/42411\/revisions"}],"predecessor-version":[{"id":42412,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/42411\/revisions\/42412"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=42411"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=42411"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=42411"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}