想给你的iPhone计算离午夜12:00点的剩余时间吗？看看小编为大家整理的在iOS中倒数计时的实例编程吧！

首先运行以安装好的 xCode

选择: File->New Project.

从 "New Project" 窗口

选择 : iPhone OS ->Applications-> View-Based Application

命名 : 我这里命名为 "minutesToMidnight"

(1)  在xCode打开 minutesToMidnightViewController.h 文件

#import

@interface minutesToMidnightViewController : UIViewController {

NSTimer *timer;

IBOutlet UILabel *countdownLabel;

}

@property(nonatomic,retain)  UILabel *countdownLabel;

@property (nonatomic, retain) NSTimer *timer;

-(void)onTimer;

@end

(2)  在xCode打开 minutesToMidnightViewController.m 文件

#import "minutesToMidnightViewController.h"

@implementation minutesToMidnightViewController

@synthesize timer;

@synthesize countdownLabel;

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

- (void)viewDidLoad {

[super viewDidLoad];

[countdownLabel setFont:[UIFont fontWithName:@"DBLCDTempBlack" size:128.0]];

countdownLabel.text = @"00:00:00";

self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(onTimer) userInfo:nil repeats: YES];

}

-(void)onTimer{

NSDate* now = [NSDate date];

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *dateComponents = [gregorian components:(NSHourCalendarUnit  | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:now]; //

NSInteger hour = [dateComponents hour];

NSInteger min = [dateComponents minute];

NSInteger sec = [dateComponents second];

sec = 60 - sec;

min = 59 - min;

hour = 23 -  hour;

[gregorian release];

countdownLabel.text = [NSString stringWithFormat:@"%d:%d:%d", hour, min,sec];

}

- (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 {

// Release any retained subviews of the main view.

// e.g. self.myOutlet = nil;

}

- (void)dealloc {

[super dealloc];

[timer release];

[countdownLabel release];

}

@end

完成后打开Interface Builder，进行UIView设置

(3) UIView 界面设置- 黑色背景，红色字体，让它看起来像一个闹钟。

双击文件： "MinutesToMidnightViewController.xib" ;

然后 "Interface Builder"  会自动打开，在这里我们可以编辑改变界面

选择： Tools -> Reveal In Document Window -> View

选择:  Tools -> Attributes Inspector

在色条内选择 "黑色"，可以看到背景变为黑色

(4) 加入 UILabel 显示我们的倒数时间

选择: Tools -> Library ; 从Library显示菜单中拖拉一个 Label 到 Main View

在主显示上点击 Label;从Label Attributes 上选着字体的颜色和字体大小。

(5)从 Interface Builder 写入 UILabel 的 class file

再打开SDK工具 Interface Builder

在主视窗口或文件窗口;点击 Label

选择: Tools -> Connection Inspector

移动鼠标在"New Referencing Outlet" 后面圆圈上; 圆圈变为(+); 拖向直线连接到"File's Owner";

放开鼠标选择键出现 "countdownLabel"; 选上它。

选择： File -> Save then close Interface Builde

最后在 xCode 选择 Build->Build and Go

以上就是小编为大家整理的在iOS中倒数计时的实例编程，希望对大家有所帮助。