iphone 使用委托（delegate）在不同的窗口之间传递数据

iphone 使用委托（delegate）在不同的窗口之间传递数据

 

在IOS里两个UIView窗口之间传递参数方法有很多，比如

 1.使用SharedApplication,定义一个变量来传递.

 2.使用文件，或者NSUserdefault来传递

 3.通过一个单例的class来传递

 4.通过Delegate来传递。

前面3种方法，暂且不说，这次主要学习如何使用通过Delegate的方法来在不同的UIView里传递数据 。

比如： 在窗口1中打开窗口2，然后在窗口2中填入一个数字，这个数字又回传给窗口1。

 

窗口1

 

窗口2

 

窗口2的结果传递给窗口1

 

 

 1.首先定义个一委托UIViewPassValueDelegate用来传递值

@protocol UIViewPassValueDelegate

- (void)passValue:(NSString *)value;

@end

 这个protocol 就是用来传递值

 

2.在窗口1的头文件里，声明delegate

#import <UIKit/UIKit.h>
#import "UIViewPassValueDelegate.h"
@interface DelegateSampleViewController : UIViewController <UIViewPassValueDelegate>
{
    UITextField *_value;
}
@property(nonatomic, retain) IBOutlet UITextField *value;

- (IBAction)buttonClick:(id)sender;

@end

 并实现这个委托

 

- (void)passValue:(NSString *)value
{
  self.value.text = value;
    NSLog(@"the get value is %@", value);
}

 

 button的Click方法，打开窗口2，并将窗口2的delegate实现方法指向窗口1。

- (IBAction)buttonClick:(id)sender
{
    ValueInputView *valueView = [[ValueInputView alloc] initWithNibName:@"ValueInputView" bundle:[NSBundle mainBundle]];
    valueView.delegate = self;
    [self setModalTransitionStyle:UIModalTransitionStyleCoverVertical];
    [self presentModalViewController:valueView animated:YES];
}

 

 第二个窗口的实现

 .h 头文件

 

#import <UIKit/UIKit.h>
#import "UIViewPassValueDelegate.h"

@interface ValueInputView : UIViewController {

    NSObject<UIViewPassValueDelegate> * delegate;
    UITextField *_value;
}

@property(nonatomic, retain)IBOutlet UITextField *value;
@property(nonatomic, retain) NSObject<UIViewPassValueDelegate> * delegate;

- (IBAction)buttonClick:(id)sender;

@end

 

 .m实现文件

 

#import "ValueInputView.h"


@implementation ValueInputView

@synthesize delegate;
@synthesize value = _value;
- (void)dealloc {
    [self.value release];
    [super dealloc];
}

- (IBAction)buttonClick:(id)sender
{
    [delegate passValue:self.value.text];
    NSLog(@"self.value.text is%@", self.value.text);
    [self dismissModalViewControllerAnimated:YES];    
   
}
- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    
    // Release any cached data, images, etc. that aren't in use.
}

- (void)viewDidUnload {
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code.
}
*/


@end

 

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