#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad
{[super viewDidLoad];[self saveNSUserDefaults];  //调用此方法将各种数据存储到NSUserDefautls中，在下面定义[self readNSUserDefaults];  //调用此方法从NSUserDefautls中读取各种数据，在下面定义
}- (void)viewDidUnload
{[txtNSString release];txtNSString = nil;[txtNSDate release];txtNSDate = nil;[txtNSArray release];txtNSArray = nil;[txtNSDictionary release];txtNSDictionary = nil;[txtInteger release];txtInteger = nil;[txtFloat release];txtFloat = nil;[txtDouble release];txtDouble = nil;[super viewDidUnload];// Release any retained subviews of the main view.
}- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}- (void)dealloc {[txtNSString release];[txtNSDate release];[txtNSArray release];[txtNSDictionary release];[txtInteger release];[txtFloat release];[txtDouble release];[super dealloc];
}//保存数据到NSUserDefaults
-(void)saveNSUserDefaults
{NSString *myString = @"enuola";int myInteger = 100;float myFloat = 50.0f;double myDouble = 20.0;NSDate *myDate = [NSDate date];NSArray *myArray = [NSArray arrayWithObjects:@"hello", @"world", nil];NSDictionary *myDictionary = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:@"enuo", @"20", nil] forKeys:[NSArray arrayWithObjects:@"name", @"age", nil]];//将上述数据全部存储到NSUserDefaults中NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];//存储时，除NSNumber类型使用对应的类型意外，其他的都是使用setObject:forKey:[userDefaults setInteger:myInteger forKey:@"myInteger"];[userDefaults setFloat:myFloat forKey:@"myFloat"];[userDefaults setDouble:myDouble forKey:@"myDouble"];[userDefaults setObject:myString forKey:@"myString"];[userDefaults setObject:myDate forKey:@"myDate"];[userDefaults setObject:myArray forKey:@"myArray"];[userDefaults setObject:myDictionary forKey:@"myDictionary"];//这里建议同步存储到磁盘中，但是不是必须的
    [userDefaults synchronize];}//从NSUserDefaults中读取数据
-(void)readNSUserDefaults
{NSUserDefaults *userDefaultes = [NSUserDefaults standardUserDefaults];//读取数据到各个label中//读取整型int类型的数据NSInteger myInteger = [userDefaultes integerForKey:@"myInteger"];txtInteger.text = [NSString stringWithFormat:@"%d",myInteger];//读取浮点型float类型的数据float myFloat = [userDefaultes floatForKey:@"myFloat"];txtFloat.text = [NSString stringWithFormat:@"%f",myFloat];//读取double类型的数据double myDouble = [userDefaultes doubleForKey:@"myDouble"];txtDouble.text = [NSString stringWithFormat:@"%f",myDouble];//读取NSString类型的数据NSString *myString = [userDefaultes stringForKey:@"myString"];txtNSString.text = myString;//读取NSDate日期类型的数据NSDate *myDate = [userDefaultes valueForKey:@"myDate"];NSDateFormatter *df = [[NSDateFormatter alloc] init];[df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];txtNSDate.text = [NSString stringWithFormat:@"%@",[df stringFromDate:myDate]];//读取数组NSArray类型的数据NSArray *myArray = [userDefaultes arrayForKey:@"myArray"];NSString *myArrayString = [[NSString alloc] init];for(NSString *str in myArray){NSLog(@"str= %@",str);myArrayString = [NSString stringWithFormat:@"%@  %@", myArrayString, str];[myArrayString stringByAppendingString:str];
//        [myArrayString stringByAppendingFormat:@"%@",str];NSLog(@"myArrayString=%@",myArrayString);}txtNSArray.text = myArrayString;//读取字典类型NSDictionary类型的数据NSDictionary *myDictionary = [userDefaultes dictionaryForKey:@"myDictionary"];NSString *myDicString = [NSString stringWithFormat:@"name:%@, age:%d",[myDictionary valueForKey:@"name"], [[myDictionary valueForKey:@"age"] integerValue]];txtNSDictionary.text = myDicString;
}@end

其实它存储在应用程序内置的一个plist文件里，这个可以根据路径看到。

比如说这个是你的程序沙盒位置
/UsersLibrary/Application Support/iPhoneSimulator/4.1/Applicati*****/29788E40-AF47-45A0-8E92-3AC0F501B7F4/,（这个是应用程序对应在mac上的位置）
这个下面有/Library/Prefereces，里面有个plist文件，存储的就是你的userDefaults
想要删掉的话，用removeObjectForKey或者删掉沙盒，也就是你的应用程序然后重新安装。