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在程序代码中设定控件调用的方法

一般情况下，我们都是通过在XIB界面中添加控件，然后在程序中编写控件方法，最后通过XIB将控件和方法进行绑定。

本文，将介绍如何直接在程序中将编写的方法与控件进行绑定。

这里的例子将继续文章《通过Window-based Application创建项目(一) 》中的示例！

操作很简单，参考下面代码中的红色部分。

FirstViewController.h 修改：

#import 

 @interface FirstViewController : UIViewController {

 UILabel *label;

 UIButton *button;

 }

 @property (nonatomic,retain) UILabel *label;

 @property (nonatomic,retain) UIButton *button;

 -(IBAction)myButtonClicked:(id)sender; 

 @end

FirstViewController.m 修改：

#import "FirstViewController.h"

 @implementation FirstViewController

 @synthesize label,button;

-(IBAction)myButtonClicked:(id)sender{

 UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@"my alert" 

   message:@"button is clicked" 

 delegate:self 

 cancelButtonTitle:@"Ok" 

 otherButtonTitles: nil];

 [alert show];

 [alert release];

 } 

 // The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.

 /*

 - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {

     self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

     if (self) {

         // Custom initialization.

     }

     return self;

 }

 */

 /*

 // Implement loadView to create a view hierarchy programmatically, without using a nib.

 - (void)loadView {

 }

 */

 // Implement viewDidLoad to do additional setup after loading the view, typically from a nib.

 - (void)viewDidLoad {

 //create the label

 CGRect frame=CGRectMake(50, 30, 200, 45);

 label=[[UILabel alloc] initWithFrame:frame];

 label.text=@"This is a label";

 //create the button

 frame=CGRectMake(50, 100, 200, 45);

 button=[UIButton buttonWithType:UIButtonTypeRoundedRect];

 button.frame=frame;

 [button setTitle:@"OK" forState:UIControlStateNormal];

[button addTarget:self 

   action:@selector(myButtonClicked:) 

 forControlEvents:UIControlEventTouchUpInside]; 

 //add the label and button into current view.

 [self.view addSubview:label];

 [self.view addSubview:button];

     [super viewDidLoad];

 }

 /*

 // Override to allow orientations other than the default portrait orientation.

 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {

     // Return YES for supported orientations.

     return (interfaceOrientation == UIInterfaceOrientationPortrait);

 }

 */

 - (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;

 }

 - (void)dealloc {

 [label release];

 [button release];

     [super dealloc];

 }

 @end

运行后，点击界面上的【OK】按钮，即显示效果如下图：

关于控件对应方法在系统中的常量定义如下表：

Control Events

Kinds of events possible for control objects.

enum {
   UIControlEventTouchDown           = 1