通知---视图间数据的传递：标签显示输入的内容【多个视图中】

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
//注冊通知
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(recieveData:)
name:BackNotification object:nil];
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];

self.view.backgroundColor = [UIColor greenColor];

//创建显示文字的label
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(50, 100, 200, 40)];
label.tag = 102;
label.backgroundColor = [UIColor grayColor];
[self.view addSubview:label];
[label release];

//加入按钮
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.frame = CGRectMake(20, 20, 90, 60);
[button setTitle:@"打开模态" forState:UIControlStateNormal];
[button addTarget:self action:@selector(buttonAction) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];

}

- (void)recieveData:(NSNotification *)notification {

UILabel *label = (UILabel *)[self.view viewWithTag:102];

NSString *text = [notification.userInfo objectForKey:@"text"];

label.text = text;

}

- (void)buttonAction {

ModalViewController *modalCtrl = [[[ModalViewController alloc] init] autorelease];

modalCtrl.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;

[self presentViewController:modalCtrl animated:YES completion:NULL];

}

#define  BackNotification     @"BackNotification"
@interface ModalViewController ()

@end

@implementation ModalViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];

self.view.backgroundColor = [UIColor redColor];

//加入按钮
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.frame = CGRectMake(20, 20, 90, 60);
[button setTitle:@"关闭模态" forState:UIControlStateNormal];
[button addTarget:self action:@selector(buttonAction) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];

//创建输入框
UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(50, 100, 200, 40)];
textField.tag = 101;
textField.borderStyle = UITextBorderStyleRoundedRect;
[self.view addSubview:textField];
[textField release];

}

- (void)buttonAction {

UITextField *field = (UITextField *)[self.view viewWithTag:101];

NSString *text = field.text;

NSDictionary *dic = @{@"text":text};

//发送通知
[[NSNotificationCenter defaultCenter] postNotificationName:BackNotification
object:self userInfo:dic];

[self dismissViewControllerAnimated:YES completion:NULL];

}