iOS开发常用代码

1、iOS 开发常用的代码%c 一个单一的字符%d 一个十进制整数%i 一个整数%e,%f,%g 一个浮点数%o 一个八进制数%s 一个字符串%x 一个十六进制数%p 一个指针%n 一个等于读取字符数量的整数%u 一个无符号整数%一个字符集%一个精度符号一、NSString/*创建字符串的方法*/1、创建常量字符串。NSString*astring=ThisisaString!;2、创建空字符串，给予赋值NSString*astring=NSStringallocinit;astring=ThisisaString!;NSLog(astring:%,astring);astringrelease;

2、3、在以上方法中，提升速度：initWithString 方法NSString*astring=NSStringallocinitWithString:ThisisaString!;NSLog(astring:%,astring);astringrelease;4、用标准 c 创建字符串：initWithCString 方法char*Cstring=ThisisaString!;NSString*astring=NSStringallocinitWithCString:Cstring;NSLog(astring:%,astring);astringrelease;5、创建格式化字符串：占位符(

3、由一个加一个字符组成)inti=1;intj=2;NSString*astring=NSStringallocinitWithString:NSStringNSLog(astring:%,astring);astringrelease;6、创建临时字符串NSString*astring;astring=NSStringstringWithCString:Thisisatemporarystring;NSLog(astring:%,astring);/*从文件读取字符串：initWithContentsOfFile 方法*/NSString*path=astring.text;NSString*

4、astring=NSStringallocinitWithContentsOfFile:path;NSLog(astring:%,astring);astringrelease;/*写字符串到文件：writeToFile 方法*/NSString*astring=NSStringallocinitWithString:ThisisaString!;NSLog(astring:%,astring);NSString*path=astring.text;astringwriteToFile:pathatomically:YES;用 C 比较:strcmp 函数charstring1=string!

5、;charstring2=string!;if(strcmp(string1,string2)=0)NSLog(1);isEqualToString 方法NSString*astring01=ThisisaString!;NSString*astring02=ThisisaString!;BOOLresult=astring01isEqualToString:astring02;NSLog(result:%d,result);compare 方法(comparer 返回的三种值)NSString*astring01=ThisisaString!;NSString*astring02=Thisi

6、saString!;BOOLresult=astring01compare:astring02=NSOrderedSame;NSLog(result:%d,result);NSOrderedSame 判断两者内容是否相同NSString*astring01=ThisisaString!;NSString*astring02=thisisaString!;/*比较两个字符串*/BOOLresult=astring01compare:astring02=NSOrderedAscending;NSLog(result:%d,result);/NSOrderedAscending 判断两对象值的大小(

7、按字母顺序进行比较，astring02 大于 astring01 为真)NSString*astring01=thisisaString!;NSString*astring02=ThisisaString!;BOOLresult=astring01compare:astring02=NSOrderedDescending;NSLog(result:%d,result);/NSOrderedDescending 判断两对象值的大小(按字母顺序进行比较，astring02 小于 astring01 为真)不考虑大小写比较字符串 1NSString*astring01=thisisaString!;

8、NSString*astring02=ThisisaString!;BOOLresult=astring01caseInsensitiveCompare:astring02=NSOrderedSame;NSLog(result:%d,result);/NSOrderedDescending 判断两对象值的大小(按字母顺序进行比较，astring02小于 astring01 为真)不考虑大小写比较字符串 2NSString*astring01=thisisaString!;NSString*astring02=ThisisaString!;BOOLresult=astring01compare:

9、astring02options:NSCaseInsensitiveSearch|NSNumericSearch=NSOrderedSame;NSLog(result:%d,result);/NSCaseInsensitiveSearch:不区分大小写比较 NSLiteralSearch:进行完全比较，区分大小写 NSNumericSearch:比较字符串的字符个数，而不是字符值。/*改变字符串的大小写*/NSString*string1=AString;NSString*string2=String;NSLog(string1:%,string1uppercaseString);/大写NSL

10、og(string2:%,string2lowercaseString);/小写NSLog(string2:%,string2capitalizedString);/首字母大小/*在审中搜索子用*/NSString*string1=Thisisastring;NSString*string2=string;NSRangerange=stringlrangeOfString:string2;intlocation=range.location;intleight=range.length;NSString*astring=NSStringallocinitWithString:NSStrings

11、tringWithFormat:Location:%i,Leight:%i”,location,leight;NSLog(astring:%,astring);astringrelease;/*抽取子用*/-substringToIndex:从字符串的开头一直截取到指定的位置，但不包括该位置的字符NSString*string1=Thisisastring;NSString*string2=string1substringToIndex:3;NSLog(string2:%,string2);-substringFromIndex:以指定位置开始(包括指定位置的字符)，并包括之后的全部字符NSS

12、tring*string1=Thisisastring;NSString*string2=string1substringFromIndex:3;NSLog(string2:%,string2);-substringWithRange:/按照所给出的位置，长度，任意地从字符串中截取子用NSString*string1=Thisisastring;NSString*string2=string1substringW 计 hRange:NSMakeRange(0,4);NSLog(string2:%,string2);constchar*fieldValue=valuecStringUsingEn

13、coding:NSUTF8StringEncoding;constchar*fieldValue=valueUTF8String;NSString 转 NSDataNSString*str=kilonet;NSData*data=strdataUsingEncoding:NSUTF8StringEncoding;Dateformat 用法：-(NSString*)getDay:(NSDate*)dNSString*s;NSDateFormatter*format=NSDateFormatterallocinit;formatsetDateFormat:YYYY/MM/ddhh:mm:ss;s=

14、formatstringFromDate:d;formatrelease;returns;)各地时区获取：NSDate*nowDate=NSDatenew;NSDateFormatter*formatter=NSDateFormatterallocinit;formattersetDateFormat:yyyy/MM/ddHH:mm:ss;/根据时区名字获取当前时间，如果该时区不存在，默认获取系统当前时区的时间/NSTimeZone*timeZone=NSTimeZonetimeZoneW 计 hName:Europe/Andorra;/formattersetTimeZone:timeZon

15、e;/获取所有的时区名字NSArray*array=NSTimeZoneknownTimeZoneNames;/NSLog(array:%,array);/for 循环/for(inti=0;iarraycount;i+)/NSTimeZone*timeZone=NSTimeZonetimeZoneWithName:arrayobjectAtIndex:i;/formattersetTimeZone:timeZone;/NSString*locationTime=formatterstringFromDate:nowDate;/NSLog(”时区名字:时区当前时间：,arrayobjectAt

16、Index:i,locationTime);/NSLog(timezonenameis:%”,arrayobjectAtIndex:i);/快速枚举法for(NSString*timeZoneNameinarray)formattersetTimeZone:NSTimeZonetimeZoneWithName:timeZoneName;NSLog(%,%”,timeZoneName,formatterstringFromDate:nowDate);formatterrelease;nowDaterelease;NSCalendar 用法：-(NSString*)getWeek:(NSDate*

17、)dNSCalendar*calendar=NSCalendarallocinitW 让 hCalendarIdentifier:NSGregorianCalendar;unsignedunits=NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSWeekdayCalendarUnit;NSDateComponents*components=calendarcomponents:unitsfromDate:d;calendarrelease;switch(componentsweekday)case 2:returnMonda

18、y;break;case 3:returnTuesday;break;case 4:returnWednesday;break;case 5:returnThursday;break;case 6:returnFriday;break;case 7:returnSaturday;break;case1:returnSunday;break;default:returnNoWeek;break;/用 components,我们可以读取其他更多的数据4.用 Get 方式读取网络数据：将网络数读取为字符串- (NSString*)getDataByURL:(NSString*)urlreturnNS

19、StringallocinitWithData:NSDatadataWithContentsOfURL:NSURLURLWithString:urlstringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncodingencoding:NSUTF8StringEncoding;/读取网络图片- (UIImage*)getImageByURL:(NSString*)urlreturnUllmageallocinitWithData:NSDatadataWithContentsOfURL:NSURLURLWithString:urlstring

20、ByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding;多线程NSThreaddetachNewThreadSelector:selector(scheduleTask)toTarget:selfwithObject:nil;- (void)scheduleTask/createapoolNSAutoreleasePool*pool=NSAutoreleasePoolallocinit;/releasethepool;poolrelease;/如果有参数，则这么使用：NSThreaddetachNewThreadSelector:sel

21、ector(scheduleTask:)toTarget:selfwithObject:NSDatedate;- (void)scheduleTask:(NSDate*)mdate/createapoolNSAutoreleasePool*pool=NSAutoreleasePoolallocinit;/releasethepool;poolrelease;/注意 selector 里有冒号。/在线程里运行主线程里的方法selfperformSelectorOnMainThread:selector(moveToMain)withObject:nilwaitUntilDone:FALSE;6.

22、定时器 NSTimer 用法：代码/一个可以自动关闭的 Alert 窗口UlAlertView*alert=UlAlertViewallocinitWithTitle:nilmessage:一个可以自动关闭的 Alert 窗口delegate:nilcancelButtonTitle:nil/NSLocalizedString(OK,OK)/取消任何按钮otherButtonTitles:nil;/alertsetBounds:CGRectMake(alert.bounds.origin.x,alert.bounds.origin.y,alert.bounds.size.width,alert

23、.bounds.size.height+30.0);alertshow;UIActivityIndicatorView*indicator=UIActivityIndicatorViewallocinitWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge;/Adjusttheindicatorsoitisupafewpixelsfromthebottomofthealertindicator.center=CGPointMake(alert.bounds.size.width/2,alert.bounds.size

24、.height-40.0);indicatorstartAnimating;alertinsertSubview:indicatoratIndex:0;indicatorrelease;NSTimerscheduledTimerWithTimeInterval:3.0ftarget:selfselector:selector(dismissAlert:)userInfo:NSDictionarydictionaryWithObjectsAndKeys:alert,alert,testing,key,nil/如果不用传递参数,那么可以将此项设置为 nil.repeats:NO;NSLog(rel

25、easealert);alertrelease;-(void)dismissAlert:(NSTimer*)timerNSLog(releasetimer);NSLog(timeruserInfoobjectForKey:key);UIAlertView*alert=timeruserInfoobjectForKey:alert;alertdismissW 让 hClickedButtonIndex:0animated:YES;定时器停止使用：timerinvalidate;timer=nil;7.用户缺省值 NSUserDefaults 读取：/得到用户缺省值NSUserDefaults*d

26、efs=NSUserDefaultsstandardUserDefaults;/在缺省值中找到 AppleLanguages,返回值是一个数组NSArray*languages=defsobjectForKey:AppleLanguages;NSLog(alllanguage 语言 is%,languages);/在得到的数组中的第一个项就是用户的首选语言了NSLog(”首选语言 is%,languagesobjectAtIndex:0);/getthelanguage&countrycodeNSLocale*currentLocale=NSLocalecurrentLocale;NS

27、Log(LanguageCodeis%,currentLocaleobjectForKey:NSLocaleLanguageCode);NSLog(CountryCodeis%,currentLocaleobjectForKey:NSLocaleCountryCode8 .View 之间切换的动态效果设置：SettingsController*settings=SettingsControllerallocinitWithNibName:SettingsViewbundle:nil;settings.modalTransitionStyle=UIModalTransitionStyleFlip

28、Horizontal;水平翻转selfpresentModalViewController:settingsanimated:YES;settingsrelease;9 .NSScrollView 滑动用法：- (void)scrollViewDidScroll:(UIScrollView*)scrollViewNSLog(正在滑动中.”)；/用户直接滑动 NSScrollView,可以看到滑动条- (void)scrollViewDidEndDecelerating:(UIScrollView*)scrollView/通过其他才$件触发 NSScrollView 滑动，看不到滑动条- (vo

29、id)scrollViewDidEndScrollingAnimation:(UIScrollView*)scrollView11.键盘处理系列/settheUIKeyboardtoswitchtoadifferenttextfieldwhenyoupressreturn/switchtextFieldtothenameofyourtextfieldtextFieldbecomeFirstResponder;srandom(time(NULL);/随机数种子idd=random();/随机数4 .iPhone 的系统目录:得至 UDocument 目录:NSArray*paths=NSSear

30、chPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);NSString*documentsDirectory=pathsobjectAtIndex:0;得到 temp 临时目录：NSString*tempPath=NSTemporaryDirectory();/得到目录上的文件地址：NSString*文件地址=目录地址 stringByAppendingPathComponent:”文件名.扩展名;5 .状态栏显示 Indicator：UlApplicationsharedAworkActivityInd

31、icatorVisible=YES;6 .appIcon 显示数字：-(void)applicationDidEnterBackground:(UIApplication*)applicationUIApplicationsharedApplicationsetApplicationIconBadgeNumber:5;7.sqlite 保存地址:代码NSArray*paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);NSString*thePath=pathsobjectAtIn

32、dex:0;NSString*filePath=thePathstringByAppendingPathComponent:kilonet1.sqlite;NSString*dbPath=NSBundlemainBundleresourcePathstringByAppendingPathComponent:kilonet2.sqlite;8.Application 退出：exit(0);9. AlertView,ActionSheet 的 cancelButton 点击事件：代码-(void)actionSheet:(UIActionSheet*)actionSheetdidDismissW

33、ithButtonIndex:(NSInteger)buttonIndexNSLog(cancelactionSheet);/当用户按下 cancel 按钮if(buttonindex=actionSheetcancelButtonIndex)exit(0);)/当用户按下 destructive 按钮/if(buttonindex=actionSheetdestructiveButtonindex)/DoSomethinghere./)-(void)alertView:(UIAlertView*)alertViewwillDismissWithButtonindex:(NSinteger)b

34、uttonindexNSLog(cancelalertView);if(buttonindex=alertViewcancelButtonindex)exit(0);)10 .给 Window 设置全局的背景图片：window.backgroundColor=UiColorcolorWithPatternimage:UiimageimageNamed:coolblack.png;11 .UlTextField 文本框显示及对键盘的控制：代码#pragmamark-#pragmamarkUlTextFieldDelegate/控制键盘跳转-(BOOL)textFieldShouldReturn:

35、(UITextField*)textFieldif(textField=_txtAccount)if(_txtAccount.textlength=0)returnNO;_txtPasswordbecomeFirstResponder;elseif(textField=_txtPassword)_txtPasswordresignFirstResponder;returnYES;/输入框背景更换-(BOOL)textFieldShouldBeginEditing:(UITextField*)textFieldtextFieldsetBackground:UIImageimageNamed:ct

36、ext_field_02.png;returnYES;-(void)textFieldDidEndEditing:(UITextField*)textFieldtextFieldsetBackground:UIImageimageNamed:ctext_field_01.png;12.UITextField 文本框前面空白宽度设置以及后面组合按钮设置:代码/给文本输入框后面加入空白_txtAccount.rightView=_btnDropDown;_txtAccount.rightViewMode=UITextFieldViewModeAlways;/给文本输入框前面加入空白CGRectfr

37、ame=_txtAccountframe;frame.size.width=5;UIView*leftview=UIViewallocinitWithFrame:frame;_txtAccount.leftViewMode=UITextFieldViewModeAlways;txtAccount.leftView=leftview;13 .UlScrollView 设置滑动不超出本身范围:fcScrollViewsetBounces:NO;14 .在 drawRect 里画文字:UIFont*f=UlFontsystemFontOfSize:20;UlColordarkGrayColorset

38、;NSString*text=hinKiloNet;textdrawAtPoint:CGPointMake(center.x,center.y)withFont:f;15. NSArray 查找是否存在对象时用 indexOfObject,如果不存在则返回为NSNotFound.16. NString 与 NSArray 之间相互转换:array=stringcomponentsSeparatedByString:,;string=arrayvalueForKey:descriptioncomponentsJoinedByString:,;17.TabController 随意切换 tabba

39、r:self.tabBarControllersetSelectedIndex:tabIndex;或者 self.tabBarController.selectedIndex=tabIndex;或者实现下面的 delegate 来扑捉 tabbar 的事件：代码-(BOOL)tabBarController:(UITabBarController*)tabBarControllershouldSelectViewController:(UIViewController*)viewControllerif(viewController.tabBarItem.titleisEqualToStrin

40、g:NSLocalizedString(Logout,nil)selfshowLogout;returnNO;returnYES;18.自定义 View 之间切换动画：代码-(void)pushController:(UIViewController*)controllerwithTransition:(UIViewAnimationTransition)transitionUlViewbeginAnimations:nilcontext:NULL;selfpushViewController:controlleranimated:NO;UIViewsetAnimationDuration:.5;UIViewsetAnimationBeginsFromCurrentState:YES;UIViewsetAnimationTransition:transitionforView:self.viewcache:YES;UIViewcommitAnimations;CATransition*transition=CATransitionanimation;transition.duration=kAnimationDuration;transition.timingFu