target-action传值

Target-Action传值

实质就是：A页面要给B页面传值,A就提供接口出去,抓A到B内部来,A间接调用自己内部方法(相当于,A把自己内部需                     要操作的方法,传到B内来,到B内部进行赋值,这样就不存在訪问不到各自的局部实例变量)

      @property (nonatomic,assign)id traget;
 @property (nonatomic,assign)SEL action;

       [self.traget performSelector:self.action withObject:nil];(是否须要传參数自己定,最多2个)

代码例如以下:

#import "FirstViewController.h"
#import "SecondViewController.h"
#import "UIButton+Create.h"
@interface FirstViewController ()
{
    UILabel * _label;
}
@end

@implementation FirstViewController
- (void)dealloc
{
    [_label release];
    [super dealloc];
}
- (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];
    self.navigationItem.title = @"首页";

    _label = [[UILabel alloc]initWithFrame:CGRectMake(50, 80, 200, 30)];
    _label.backgroundColor = [UIColor greenColor];

    //    _label.text = self.text;
    [self.view addSubview:_label];

    UIButton * button = [UIButton systemButtonWithFrame:CGRectMake(100, 120, 50, 50) title:@"Push" target:self action:@selector(didClickButtonAction)];
    [self.view addSubview:button];

	// Do any additional setup after loading the view.
}

- (void)didClickButtonAction
{

    SecondViewController * secondVC = [[SecondViewController alloc]init];
    secondVC.target = self;
    secondVC.action = @selector(didClick:);
    [self.navigationController pushViewController:secondVC animated:YES];
    [secondVC release];
}

- (void)didClick:(NSString *)text
{
    _label.text = text;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

#import <UIKit/UIKit.h>

@interface SecondViewController : UIViewController

@property (nonatomic,assign)id target;
@property (nonatomic,assign)SEL action;
@end

#import "SecondViewController.h"
#import "FirstViewController.h"
#import "UIButton+Create.h"
@interface SecondViewController ()
{
    UITextField * _textField;//创建一个输入框
}
@end
@implementation SecondViewController

- (void)dealloc
{
    [_textField release];
    [super dealloc];
}
- (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 orangeColor];
    self.navigationItem.title = @"第二页";

    _textField = [[UITextField alloc]initWithFrame:CGRectMake(50, 80, 200, 30)];
    _textField.borderStyle = UITextBorderStyleRoundedRect;
    [self.view addSubview:_textField];

    UIButton * button = [UIButton systemButtonWithFrame:CGRectMake(100, 120, 50, 50) title:@"Back" target:self action:@selector(didClickButtonAction)];
    [self.view addSubview:button];

	// Do any additional setup after loading the view.
}

- (void)didClickButtonAction
{
    [_target performSelector:_action withObject:_textField.text];
    [self.navigationController popToRootViewControllerAnimated:YES];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end