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 <UIKit/UIKit.h>

@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];

[email protected]"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：

在程序代码中设定控件调用的方法

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 <<  0,
   UIControlEventTouchDownRepeat     = 1 <<  1,
   UIControlEventTouchDragInside     = 1 <<  2,
   UIControlEventTouchDragOutside    = 1 <<  3,
   UIControlEventTouchDragEnter      = 1 <<  4,
   UIControlEventTouchDragExit       = 1 <<  5,
   UIControlEventTouchUpInside       = 1 <<  6,
   UIControlEventTouchUpOutside      = 1 <<  7,
   UIControlEventTouchCancel         = 1 <<  8,
   
   UIControlEventValueChanged        = 1 << 12,
   
   UIControlEventEditingDidBegin     = 1 << 16,
   UIControlEventEditingChanged      = 1 << 17,
   UIControlEventEditingDidEnd       = 1 << 18,
   UIControlEventEditingDidEndOnExit = 1 << 19,
   
   UIControlEventAllTouchEvents      = 0x00000FFF,
   UIControlEventAllEditingEvents    = 0x000F0000,
   UIControlEventApplicationReserved = 0x0F000000,
   UIControlEventSystemReserved      = 0xF0000000,
   UIControlEventAllEvents           = 0xFFFFFFFF
};