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:%"

2、,astring);astringrelease;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;

3、NSLog("astring：%",astring);astringrelease;5、创建格式化字符串：占位符(由一个%加一个字符组成)inti=1;intj=2;NSString*astring=NSStringallocinitWithString：NSStringstringWithFormat："%d.Thisis%istring!",i,j;NSLog("astring:%",astring);astringrelease;6、创建临时字符串NSString*astring;astring=NSStringstringWi

4、thCString:"Thisisatemporarystring"NSLog("astring:%",astring);/*从文件读取字符串:initWithContentsOfFile方法*/NSString*path="astring.text"NSString*astring=NSStringallocinitWithContentsOfFile:path;NSLog("astring:%",astring);astringrelease;/*写字符串到文件:writeToFile方法*/NSString*

5、astring=NSStringallocinitWithString:"ThisisaString!"NSLog("astring:%",astring);NSString*path="astring.text"astringwriteToFile:pathatomically:YES;astringrelease;/*比较两个字符串*/用C比较:strcmp函数charstring1="string!"charstring2="string!"if(strcmp(string1,string

6、2)=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*astrin

7、g02="ThisisaString!"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!"BOOLresult=astring01compare:astring02=NSOrderedAscending;NSLog("

8、result:%d",result);/NSOrderedAscending判断两对象值的大小(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(

9、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!"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

10、)不考虑大小写比较字符串2NSString*astring01="thisisaString!"NSString*astring02="ThisisaString!"BOOLresult=astring01compare: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N

11、SNumericSearch: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NSLog("string2:%",string2lowercaseString);/小写NSLog("string2:%",string2capitalizedString);/首字母大小/*在串中搜索子串*/NS

12、String*string2="string"NSString*string1="Thisisastring"NSRangerange=string1rangeOfString:string2;intlocation=range.location;intleight=range.length;NSString*astring=NSStringallocinitWithString:NSStringstringWithFormat:"Location:%i,Leight:%i",location,leight;NSLog("a

13、string:%",astring);astringrelease;/*抽取子串*/但不包括该位，并包括之-substringToIndex:从字符串的开头一直截取到指定的位置，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)后的全部字符NSString*string1="Thisisastring

14、"NSString*string2=string1substringFromIndex:3;-substringWithRange:/按照所给出的位置，长度，任意地从字符串中截取子串NSString*string1="Thisisastring"NSString*string2=string1substringWithRange:NSMakeRange(0,4);NSLog("string2:%",string2);constchar*fieldValue=valuecStringUsingEncoding:NSUTF8StringEncodi

15、ng;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=format

16、stringFromDate: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=NSTimeZonetimeZoneWithName:"Europe/Andorra"/formattersetTi

17、meZone:timeZone;/获取所有的时区名字NSArray*array=NSTimeZoneknownTimeZoneNames;/NSLog("array:%",array);/for循环/for(inti=0;i<arraycount;i+)/NSTimeZone*timeZone=NSTimeZonetimeZoneWithName:arrayobjectAtIndex:i;/formattersetTimeZone:timeZone;/NSString*locationTime=formatterstringFromDate:nowDate;/NSLo

18、g("时区名字:%:时区当前时间:%",arrayobjectAtIndex:i,locationTime);/NSLog("timezonenameis:%",arrayobjectAtIndex:i);/快速枚举法for(NSString*timeZoneNameinarray)formattersetTimeZone:NSTimeZonetimeZoneWithName:timeZoneName;NSLog("%,%",timeZoneName,formatterstringFromDate:nowDate);formatter

19、release;nowDaterelease;NSCalendar用法：-(NSString*)getWeek:(NSDate*)dNSCalendar*calendar=NSCalendarallocinitWithCalendarIdentifier:NSGregorianCalendar;unsignedunits=NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSWeekdayCalendarUnit;NSDateComponents*components=calendarcomponents:unitsfromDat

20、e:d;calendarrelease;switch(componentsweekday)case2:return"Monday"break;case3:return"Tuesday"break;case4:return"Wednesday"break;case5:return"Thursday"break;case6:return"Friday"break;case7:return"Saturday"break;case1:return"Sunday"b

21、reak;default:return"NoWeek"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*)urlreturnNSStringallocinitWithData:NSDatadataWithContentsOfURL:NSURLURLWithString:urlstringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncodingencoding:NSUTF8StringEn

22、coding;/读取网络图片-(UIImage*)getImageByURL:(NSString*)urlreturnUIImageallocinitWithData:NSDatadataWithContentsOfURL:NSURLURLWithString:urlstringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding;多线程NSThreaddetachNewThreadSelector:selector(scheduleTask)toTarget:selfwithObject:nil;-(void)scheduleTas

23、k/createapoolNSAutoreleasePool*pool=NSAutoreleasePoolallocinit;/releasethepool;poolrelease;/如果有参数，则这么使用：NSThreaddetachNewThreadSelector:selector(scheduleTask:)toTarget:selfwithObject:NSDatedate;-(void)scheduleTask:(NSDate*)mdate/createapoolNSAutoreleasePool*pool=NSAutoreleasePoolallocinit;/releaseth

24、epool;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. 定时器NSTimer用法：代码/一个可以自动关闭的Alert窗口UIAlertView*alert=UIAlertViewallocinitWithTitle:nilmessage:"一个可以自动关闭的Alert窗口"delegate:nilcancelButtonTitle:nil/NSLocalize

25、dString("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.bounds.size.height+30.0);alertshow;UIActivityIndicatorView*indicator=UIActivityIndicatorViewallocinitWithActivityIndicatorStyle:UIAc

26、tivityIndicatorViewStyleWhiteLarge;/Adjusttheindicatorsoitisupafewpixelsfromthebottomofthealertindicator.center=CGPointMake(alert.bounds.size.width/2,alert.bounds.size.height-40.0);indicatorstartAnimating;alertinsertSubview:indicatoratIndex:0;indicatorrelease;NSTimerscheduledTimerWithTimeInterval:3.

27、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("releasealert");alertrelease;-(void)dismissAlert:(NSTimer*)timerNSLog("releasetimer&qu

28、ot;);NSLog(timeruserInfoobjectForKey:"key");UIAlertView*alert=timeruserInfoobjectForKey:"alert"alertdismissWithClickedButtonIndex: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*defs=NSUserDefaultsstandardUserDefaults;/在缺省值中找到AppleL

29、anguages,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;NSLog("LanguageCodei

30、s%",currentLocaleobjectForKey:NSLocaleLanguageCode);NSLog("CountryCodeis%",currentLocaleobjectForKey:NSLocaleCountryCode8. View之间切换的动态效果设置：SettingsController*settings=SettingsControllerallocinitWithNibName:"SettingsView"bundle:nil;settings.modalTransitionStyle=UIModalTransit

31、ionStyleFlipHorizontal;/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/通过其他控件触发NSScrollV

32、iew滑动，看不到滑动条-(void)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:/得到Document目录：NSArray

33、*paths=NSSearchPathForDirectoriesInDomains(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：文件NSString*文件地址=目录地址stringByAppendingPathComponent:"名.扩展名"5. 状态栏显示Indicator：UIApplicationsha

34、redAworkActivityIndicatorVisible=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);

35、NSString*thePath=pathsobjectAtIndex: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

36、)actionSheet:(UIActionSheet*)actionSheetdidDismissWithButtonIndex:(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:(UIAl

37、ertView*)alertViewwillDismissWithButtonIndex:(NSInteger)buttonIndexNSLog("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. UITextField文本框显示及对键盘的控制代码#pr

38、agmamark-#pragmamarkUITextFieldDelegate/控制键盘跳转-(BOOL)textFieldShouldReturn:(UITextField*)textFieldif(textField=_txtAccount)if(_txtAccount.textlength=0)returnNO;_txtPasswordbecomeFirstResponder;elseif(textField=_txtPassword)_txtPasswordresignFirstResponder;returnYES;/输入框背景更换-(BOOL)textFieldShouldBegi

39、nEditing:(UITextField*)textFieldtextFieldsetBackground:UIImageimageNamed:"ctext_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

40、.rightView=_btnDropDown;_txtAccount.rightViewMode=UITextFieldViewModeAlways;/给文本输入框前面加入空白CGRectframe=_txtAccountframe;frame.size.width=5;UIView*leftview=UIViewallocinitWithFrame:frame;_txtAccount.leftViewMode=UITextFieldViewModeAlways;_txtAccount.leftView=leftview;13. UIScrollView设置滑动不超出本身范围：fcScrol

41、lViewsetBounces:NO;14. 在drawRect里画文字：UIFont*f=UIFontsystemFontOfSize:20;UIColordarkGrayColorset;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.NString与NSArray之间相互转换:array=stringcomponentsSeparatedByS

42、tring:","string=arrayvalueForKey:"description"componentsJoinedByString:","16. TabController随意切换tabbar：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*

43、)tabBarControllershouldSelectViewController:(UIViewController*)viewControllerif(viewController.tabBarItem.titleisEqualToString:NSLocalizedString("Logout",nil)selfshowLogout;returnNO;returnYES;17. 自定义View之间切换动画：代码-(void)pushController:(UIViewController*)controllerwithTransition:(UIViewAnima

44、tionTransition)transitionUIViewbeginAnimations:nilcontext:NULL;selfpushViewController:controlleranimated:NO;UIViewsetAnimationDuration:.5;UIViewsetAnimationBeginsFromCurrentState:YES;UIViewsetAnimationTransition:transitionforView:self.viewcache:YES;UIViewcommitAnimations;CATransition*transition=CATransitionanimatio