NSDictionary 字典 KVC 的使用

字典分為不可變字典(nsdictionary)和可變字典(nsmutabledictionary)

/* 不可變字典 */

1.建立字典 

nsdictionary *dic = [nsdictionary dictionarywithobjectsandkeys:

@"male",@"***",
@"20", @"age",
@"tom", @"name",
@"run", @"hobby", nil];

2.獲取所有的key值和value值

[dic allkeys];

[dic allvalues];

3.根據key值來獲取value值

[dic valueforkey:@"name"];

[dic objectforkey:@"name"];

4.遍歷字典 

nsarray *arr = [dic allkeys];

for (int i = 0; i < [arr count]; i++)

for (nsstring *key in dic)

//寫法2雖然寫的是遍歷字典,實際上還是遍歷陣列[dic allkeys];

/* 可變字典 */

1. 建立可變字典

nsmutabledictionary *mdic = [nsmutabledictionary dictionarywithobjectsandkeys:

@"male",@"***",
@"20", @"age",nil];

2.增加鍵值對

[mdic setvalue:@"tom" forkey:@"name"];

[mdic setobject:@"running" forkey:@"hobby"];

3.修改鍵值對

[mdic setvalue:@"18" forkey:@"age"];

//跟2.增加鍵值對方法是一樣的, 這個key值要是有就覆蓋掉原來的value, 如果沒有這個key值就相當於新新增一對鍵值對

4.刪除鍵值對

[mdic removeobjectforkey:@"age"];

[mdic setvalue:nil forkey:@"age"];

model 類*/

oc中 繼承於 nsobject 的這些類統稱  model 類 (用於訪問字串)

model類更像可變字典

例題1 把下列格式的輸出用字典-陣列巢狀的形式寫出, 並轉成model類的形式 (

;header = (

); }

) [1]字典-陣列巢狀

nsmutablearray *bigarray = [nsmutablearray array];

nsmutabledictionary *bigdic = [nsmutabledictionary dictionary];
[bigarray addobject:bigdic];
nsmutabledictionary *bodydic = [nsmutabledictionary dictionary];
[bodydic setobject:@"錯誤資訊" forkey:@"message"];
[bodydic setobject:@"1" forkey:@"errorcode"];
[bigdic setobject:bodydic forkey:@"body"];
nsmutablearray *headerarray = [nsmutablearray array];
[bigdic setobject:headerarray forkey:@"header"];
nsmutabledictionary *little = [nsmutabledictionary dictionary];
[headerarray addobject:little];
[little setobject:@"10" forkey:@"page"];
[little setobject:@"婚紗" forkey:@"title"];
[little setobject:@"fwefasd" forkey:@"content"];
nsmutablearray *images = [nsmutablearray array];
[images addobject:@""];
[images addobject:@""];
[images addobject:@""];
[little setobject:images forkey:@"image"];

[2] model類的形式

//建立model類要從結構裡往外建立

1.建立headermodel

@inte***ce headermodel : nsobject

@inte***ce bodymodel : nsobject

3.建立bigmodel

@class bodymodel;

@inte***ce bigmodel : nsobject

.h

@class bigmodel;

@inte***ce tools : nsobject
+ (bigmodel *)getbigmodel;

#import "tools.h"

#import "bigmodel.h"
#import "bodymodel.h"
#import "headermodel.h"
@implementation tools
+ (bigmodel *)getbigmodel
+ (nsstring *)getvaluefrom:(nsmutablearray *)array key:(nsstring *)content

main.m

nsmutablearray *bigarray = [nsmutablearray array];

bigmodel *b1 = [tools getbigmodel];
[bigarray addobject:b1];
bigmodel *b2 = [tools getbigmodel];
[bigarray addobject:b2];

/*kvc

*/key - value - coding

1. 給屬性賦值:

[dic setvalue:<#(id)#> forkey:<#(nsstring *)#>];

2. 最大的用處: 字典和model 的轉換

3.通過字典給model 賦值:

[model setvaluesforkeyswithdictionary:<#(nsdictionary *)#>];

必須在model類裡重寫:

-(void)setvalue:(id)value forkey:(nsstring *)key

空著就可以, 

如果沒有定義這個屬性, 就什麼都不用寫

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