9. iOS 编程之 使用 NSUserDefaults 读取、保存应用程序参数

1、认识一下 NSUserDefaults

平时我们可能要不离开应用程序，直接在应用程序里边设置配置的参数等，这就需要用到 NSUserDefaults，而 NSUserDefaults 是一个单例类，每个应用程序只有一个 NSUserDefaults 对象。

1）获取 NSUserDefaults 实例的方法（Getting the Shared NSUserDefaults Instance）

+ (NSUserDefaults *)standardUserDefaults：返回默认对象。

+ (void)resetStandardUserDefaults：重置用户默认对象。

2）获取默认值（Getting Default Values）

- (NSArray
*)arrayForKey:(NSString
*)defaultName

- (BOOL)boolForKey:(NSString
*)defaultName

- (NSData
*)dataForKey:(NSString
*)defaultName

- (NSDictionary
*)dictionaryForKey:(NSString
*)defaultName

- (float)floatForKey:(NSString
*)defaultName

- (NSInteger)integerForKey:(NSString
*)defaultName

- (id)objectForKey:(NSString
*)defaultName

- (NSArray
*)stringArrayForKey:(NSString
*)defaultName

- (NSString
*)stringForKey:(NSString
*)defaultName

- (double)doubleForKey:(NSString
*)defaultName

- (NSURL
*)URLForKey:(NSString
*)defaultName

3）设置默认值（Setting Default Values）

- (void)setBool:(BOOL)value

         forKey:(NSString
*)defaultName

- (void)setFloat:(float)value

          forKey:(NSString
*)defaultName

- (void)setInteger:(NSInteger)value

            forKey:(NSString
*)defaultName

- (void)setObject:(id)value

           forKey:(NSString
*)defaultName

- (void)setDouble:(double)value

           forKey:(NSString
*)defaultName

- (void)setURL:(NSURL
*)url

        forKey:(NSString
*)defaultName

还有好多好多的方法，属性，请参考官方文档。

2、代码示例

@implementation ViewController

- (void)viewDidLoad {

[super
viewDidLoad];

}

- (void)didReceiveMemoryWarning {

[super
didReceiveMemoryWarning];

}

- (IBAction)save:(id)sender {

//获取默认配置文件

NSUserDefaults *userDefaults = [NSUserDefaults
standardUserDefaults];

[userDefaults setValue:self.userName.text
forKey:@"userName"];

[userDefaults setValue:self.userPassword.text
forKey:@"userPassword"];

[userDefaults setObject:self.phone.text
forKey:@"phone"];

[userDefaults setObject:self.address.text
forKey:@"address"];

NSArray *addList =
@[self.add1.text,self.add2.text,self.add3.text];

[userDefaults setValue:addList
forKey:@"addList"];

//马上提交保存

[userDefaults synchronize];

self.show.text =
@"set value success";

//打印沙盒位置，方便查看（可省略）

NSLog(@"[%@]",
NSHomeDirectory());

}

- (IBAction)get:(id)sender {

NSUserDefaults *userDefaults = [NSUserDefaults
standardUserDefaults];

NSString *username = [userDefaults
objectForKey:@"userName"];

NSString *userpassword = [userDefaults
objectForKey:@"userPassword"];

NSString *phone = [userDefaults
objectForKey:@"phone"];

NSString *address = [userDefaults
objectForKey:@"address"];

NSArray *addlist = [userDefaults
objectForKey:@"addList"];

[self.userName
setText:username];

[self.userPassword
setText:userpassword];

[self.phone
setText:phone];

[self.address
setText:address];

[self.add1
setText:addlist[0]];

[self.add2
setText:addlist[1]];

[self.add3
setText:addlist[2]];

self.show.text =
@"get value success";

}

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

[self.userName
resignFirstResponder];

[self.userPassword
resignFirstResponder];

[self.phone
resignFirstResponder];

[self.address
resignFirstResponder];

[self.add1
resignFirstResponder];

[self.add2
resignFirstResponder];

[self.add3
resignFirstResponder];

}

@end

3、运行结果