实例iPhone编程入门教程-第一天

DAY ONE-MinutesToMidnight

大家一起来建立我们的第一个iPhone app，给你的iPhone计算离午夜12:00点的剩余时间。

现在已经改为：sdk4.2版本。

一切版权归http://blog.sina.com.cn/iphonesdk 所有。

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

(红色为所添加的代码)

#import<UIKit/UIKit.h>

@interface minutesToMidnightViewController : UIViewController{

NSTimer *timer;

IBOutletUILabel *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 afterloading the view, typically from a nib.

- (void)viewDidLoad {

[superviewDidLoad];

[countdownLabel setFont:[UIFontfontWithName:@"DBLCDTempBlack" size:128.0]];

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

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

}

-(void)onTimer{

NSDate* now =[NSDate date];

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

NSDateComponents *dateComponents = [gregoriancomponents:(NSHourCalendarUnit |NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:now];//不换行

NSIntegerhour = [dateComponents hour];

NSIntegermin = [dateComponents minute];

NSIntegersec = [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 {

// Releasesthe view if it doesn't have a superview.

[superdidReceiveMemoryWarning];

// Releaseany cached data, images, etc that aren't in use.

}

- (void)viewDidUnload {

// Releaseany retained subviews of the main view.

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

}

- (void)dealloc {

[superdealloc];

[timerrelease];

[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 -> AttributesInspector

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 InterfaceBuilder

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 InterfaceBuilde

最后在 xCode 选择 Build->Build and Go.

下载今天程序文件:

MinsToMidnight.zip