1杜秸、圖片拉伸
QQ20171020-183930@2x.png
2放仗、KVC的使用
KVC: Key Value Coding(鍵值編碼)
#import <Foundation/Foundation.h>
#import "XMGPerson.h"
#import "XMGDog.h"
int main(int argc, const char * argv[]) {
@autoreleasepool {
/**
取出數(shù)組中所有模型的某個(gè)屬性值
*/
XMGPerson *person1 = [[XMGPerson alloc] init];
person1.name = @"zhangsan";
person1.money = 12.99;
XMGPerson *person2 = [[XMGPerson alloc] init];
person2.name = @"zhangsi";
person2.money = 22.99;
XMGPerson *person3 = [[XMGPerson alloc] init];
person3.name = @"wangwu";
person3.money = 122.99;
NSArray *allPersons = @[person1, person2, person3];
NSArray *allPersonName = [allPersons valueForKeyPath:@"name"];
NSLog(@"%@", allPersonName);
}
return 0;
}
/**
* 把模型轉(zhuǎn)成字典
*/
void test6(){
XMGPerson *person = [[XMGPerson alloc] init];
person.name = @"lurry";
person.money = 21.21;
NSDictionary *dict = [person dictionaryWithValuesForKeys:@[@"name", @"money"]];
NSLog(@"%@", dict);
}
/**
* 取值
*/
void test5(){
XMGPerson *person = [[XMGPerson alloc] init];
person.name = @"張三";
person.money = 12332;
// 利用kvc取值
NSLog(@"%@ --- %.2f", [person valueForKeyPath:@"name"], [[person valueForKey:@"money"] floatValue]);
}
/**
作用: 字典轉(zhuǎn)模型
開發(fā)中是不建議使用setValuesForKeysWithDictionary:
1> 字典中的key必須在模型的屬性中找到
2> 如果模型中帶有模型,setValuesForKeysWithDictionary不好使
應(yīng)用場(chǎng)景: 簡(jiǎn)單的字典轉(zhuǎn)模型 ---> 框架 (MJExtention)
*/
void test4(){
NSDictionary *dict = @{
@"name" :@"lurry",
@"money" : @189.88,
@"dog" : @{
@"name" : @"wangcai",
@"price" : @8
},
@"books": @[
@{@"name" :@"iOS快速開發(fā)", @"price" : @1999},
@{@"name" :@"iOS快速發(fā)", @"price" : @199},
@{@"name" :@"iOS快開發(fā)", @"price" : @99}
]
};
XMGPerson *person = [[XMGPerson alloc] initWithDict:dict];
NSLog(@"%@", person.dog.class);
[person setValue: @{
@"name" : @"wangcai",
@"price" : @8
} forKeyPath:@"dog"];
}
/**
* 利用KVC修改類的私有成員變量(UIPageControl)
*/
void test3(){
XMGPerson *person = [[XMGPerson alloc] init];
// person->_age
// 利用KVC修改類的私有成員變量
[person printAge];
[person setValue:@"88" forKeyPath:@"_age"]; // age _age
[person printAge];
}
/**
* 利用KVC進(jìn)行綜合賦值
*/
void test2(){
XMGPerson *person = [[XMGPerson alloc] init];
person.dog = [[XMGDog alloc] init];
// person.dog.name = @"旺財(cái)";
// KVC賦值
/*
forKey和forKeyPath
1>forKeyPath 包含了所有 forKey 的功能
2>forKeyPath 進(jìn)行內(nèi)部的點(diǎn)語法,層層訪問內(nèi)部的屬性
3>注意: key值一定要在屬性中找到
*/
// [person.dog setValue:@"阿黃" forKey:@"name"];
[person setValue:@"旺財(cái)" forKeyPath:@"dog.name"];
NSLog(@"%@", person.dog.name);
}
/**
* 利用KVC進(jìn)行簡(jiǎn)單賦值
*/
void test(){
XMGPerson *person = [[XMGPerson alloc] init];
// 常規(guī)賦值
/*
person.name = @"張三";
person.age = 18;
*/
// KVC賦值
[person setValue:@"王五" forKey:@"name"];
[person setValue:@"19" forKeyPath:@"money"]; // 自動(dòng)類型轉(zhuǎn)換
NSLog(@"%@-----%.2f", person.name, person.money);
}
3、KVO的使用
KVO: Key Value Observing (鍵值監(jiān)聽)--->當(dāng)某個(gè)對(duì)象的屬性值發(fā)生改變的時(shí)候(用KVO監(jiān)聽)
#import "ViewController.h"
#import "XMGPerson.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
XMGPerson *person = [[XMGPerson alloc] init];
person.name = @"zs";
/*
作用:給對(duì)象綁定一個(gè)監(jiān)聽器(觀察者)
- Observer 觀察者
- KeyPath 要監(jiān)聽的屬性
- options 選項(xiàng)(方法方法中拿到屬性值)
*/
[person addObserver:self forKeyPath:@"name" options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:nil];
person.name = @"ls";
person.name = @"ww";
// 移除監(jiān)聽
[person removeObserver:self forKeyPath:@"name"];
}
/**
* 當(dāng)監(jiān)聽的屬性值發(fā)生改變
*
* @param keyPath 要改變的屬性
* @param object 要改變的屬性所屬的對(duì)象
* @param change 改變的內(nèi)容
* @param context 上下文
*/
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context{
NSLog(@"%@------%@------%@", keyPath, object, change);
}
@end
