IOS开发 NSUserDfaults

本节学习内容：

1.NSUserDefaults基本概念

2.NSUserDefaults函数方法

3.NSUserDefaults的使用

setObjectForKey:根据值和Key存储对象

setInteger:存储整型值

setBoool:存储布尔值

objectForKey:根据Key获取对象值

integerForKey:获取整形值根据Key

boolForKey:获取布乐值根据Key

---

【ViewController.m】

-(void)viewDidLoad{

super viewDidLoad];

UIbutton* btn=[UIButton buttonWithType:UIButtonTypeRoundedRect];

btn.frame=CGRectMake(100,100,80,40);

[btn.frame=CGRectMake(100,100,80,40);

[btn setTitle:@"写入文件"forState:UIcontrolStateNormal];

//添加事件函数

[btn addTarget:self action:@selector(pressWrite)forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:btn];

UIbutton* btnRead=[UIButton buttonWithType:UIButtonTypeRoundedRect];

btnRead.frame=CGRectMake(100,200,80,40);

[btnRead setTitle:@"读出文件"forState:UIControlStateNormal];

[btnRead addTarget:self action:@selector(pressRead)forControlEvents:UIcontrolEventTouchUpInside];

[self.view addSubview:btnRead];

}

//按下写入数据按钮

-(void)pressWrite{

//定义一个用户默认数据对象，不需求alloc创建，用户默认数据对象单例模式，standardUserDefaults:获取全局唯 一的实例对象

NSUserDfaults* ud=[NSUserDefaults standardUserDefaults];

//存储字符吕对象，可以将对象存储到内部文件中，参数1：要存储的对象（id)，参数2：对象的名字(字符串 NSString)

[ud setObject:@"Michael" forKey:@"NAME"];

NSNumber* num=[NSNumber numberWithInt:100];

//存储数据对象。只能存储能够文件 化的对象

[ud setObject:num forKey:@"NUM"];

//不能存储动态创建的对象，不能存储不能文件化的对象

//[ud setObject:self.view forKey:@"VIEW"];

//存储整形数据

[ud setInteger:123 forKey:@"INT"];

//存储布尔型

[ud setBool:YES forKey:@"BOOL"];

//存储浮点型

[ud setFloat:1.555 forKey:@"FLOAT"];

//创建一个可文件化的数组

NSArray* array=【NSArray arrayWithObjects:@"11",@"22",@""33,nil】;

[ud setObject:array forKey:@""ARRAY];

//删除写入元素

[ud removeObjectForKey:@"ARRAY"];

}

-(void)pressRead{

NSUserDefaultes* ud=[NSUserDefaults standardUserDefalults];

id object=[ud objectForKey:@"NAME"];

NSString* name=(NSString*)object;

NSLog(@"name=%@",name);

//输出结果：name=Michael

object=[ud objectForKey:@"NUM"]

NSNumber* num=(NSNumber*)object;

NSLog(@"num=%@,num");

//输出结果：num=100

NSInteger iV=[ud integerForKey:@"INT"];

NSLog(@"iV=%ld",iV);

//输出结果：iV=123

BOOL bv=[ud boolForKey:@"BOOL"];

float fv=[ud floatForKey:@"FLOAT"];

NSLog(@"bv=%d",bv);

//输出结果 bv=1

NSLog(@"fv=%f",fv);

//输出结果 fv=1.555000

NSArray* array=[ud objectForKey:@"ARRAY"];

NSLog(@"array=%@",array);

//输出结果: arry=nil

}