25条iOS开发中类型的转换和常用的知识点-总结
2014-07-01 19:32
459 查看
转自：http://www.cnblogs.com/pengyingh/articles/2382942.html
在写代码的时候很容易被一些那些我们看似简单的问题难住，也严重影响了我们工作的进度，所以今天把一些在iOS中常用 关于类型的转换和常用的用法总结下。
字符的表示含义：
%c 一个单一的字符
%d 一个十进制整数
%i 一个整数 //原来i%是这个区别啊
%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 //也挺特别的
%n 一个等于读取字符数量的整数 //特别的东东
%u 一个无符号整数
%[] 一个字符集 //没见过
%% 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 = @”This is a String!”;
2、创建空字符串，给予赋值。
NSString *astring = [[NSString alloc] init];
astring = @”This is a String!”;
NSLog(@”astring:%@”,astring); //NSLog要这么用？反正当直接使用NSLog(astring)会有警告
[astring release];
3、在以上方法中，提升速度:initWithString方法
NSString *astring = [[NSString alloc] initWithString:@”This is a String!”];
NSLog(@”astring:%@”,astring);
[astring release];
4、用标准c创建字符串:initWithCString方法
char *Cstring = “This is a String!”;
NSString *astring = [[NSString alloc] initWithCString:Cstring];
NSLog(@”astring:%@”,astring);
[astring release];
5、创建格式化字符串:占位符（由一个%加一个字符组成）
int i = 1;
int j = 2;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];
NSLog(@”astring:%@”,astring);
[astring release];
6、创建临时字符串
NSString *astring;
astring = [NSString stringWithCString:"This is a temporary string"];
NSLog(@”astring:%@”,astring);
/*—————-从文件读取字符串:initWithContentsOfFile方法 —————-*/
NSString *path = @”astring.text”;
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@”astring:%@”,astring);
[astring release];
/*—————-写字符串到文件:writeToFile方法 —————-*/
NSString *astring = [[NSString alloc] initWithString:@”This is a String!”];
NSLog(@”astring:%@”,astring);
NSString *path = @”astring.text”;
[astring writeToFile: path atomically: YES];
[astring release];
/*—————- 比较两个字符串—————-*/
用C比较:strcmp函数
char string1[] = “string!”;
char string2[] = “string!”;
if(strcmp(string1, string2) = = 0)
{
NSLog(@”1″);
}
isEqualToString方法
NSString *astring01 = @”This is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 isEqualToString:astring02];
NSLog(@”result:%d”,result);
compare方法(comparer返回的三种值)
NSString *astring01 = @”This is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 compare:astring02] = = NSOrderedSame;
NSLog(@”result:%d”,result);
NSOrderedSame 判断两者内容是否相同
NSString *astring01 = @”This is a String!”;
NSString *astring02 = @”this is a String!”;
BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;
NSLog(@”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 = @”this is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 compare: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1
NSString *astring01 = @”this is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 caseInsensitiveCompare: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2
NSString *astring01 = @”this is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 compare:astring02
options: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 = @”A String”;
NSString *string2 = @”String”;
NSLog(@”string1:%@”,[string1 uppercaseString]);//大写
NSLog(@”string2:%@”,[string2 lowercaseString]);//小写
NSLog(@”string2:%@”,[string2 capitalizedString]);//首字母大小
/*—————-在串中搜索子串 —————-*/
NSString *string1 = @”This is a string”;
NSString *string2 = @”string”;
NSRange range = [string1 rangeOfString:string2];
int location = range.location;
int leight = range.length;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%i,Leight:%i",location,leight]];
NSLog(@”astring:%@”,astring);
[astring release];
/*—————-抽取子串 —————-*/
-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 = @”This is a string”;
NSString *string2 = [string1 substringToIndex: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
NSString *string1 = @”This is a string”;
NSString *string2 = [string1 substringFromIndex: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串
NSString *string1 = @”This is a string”;
NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];
NSLog(@”string2:%@”,string2);
const char *fieldValue = [value cStringUsingEncoding:NSUTF8StringEncoding];
const char *fieldValue = [value UTF8String];
NSString 转 NSData
NSString* str= @”kilonet”;
NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding];
Date format用法：
-(NSString *) getDay:(NSDate *) d
{
NSString *s ;
NSDateFormatter *format = [[NSDateFormatter alloc] init];
[format setDateFormat:@"YYYY/MM/dd hh:mm:ss"];
s = [format stringFromDate:d];
[format release];
return s;
}
各地时区获取：
代码
NSDate *nowDate = [NSDate new]; //竟然是这个样子，干嘛，四不像。你以为你是c++啊
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy/MM/dd HH: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 = [NSTimeZone timeZoneWithName:@"Europe/Andorra"];
// [formatter setTimeZone:timeZone];
//获取所有的时区名字
NSArray *array = [NSTimeZone knownTimeZoneNames];
// NSLog(@”array:%@”,array);
//for循环
// for(int i=0;i<[array count];i++)
// {
// NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:[array objectAtIndex:i]];
// [formatter setTimeZone:timeZone];
// NSString *locationTime = [formatter stringFromDate:nowDate];
// NSLog(@"时区名字:%@ : 时区当前时间: %@",[array objectAtIndex:i],locationTime);
// //NSLog(@"timezone name is:%@",[array objectAtIndex:i]);
// }
//快速枚举法
for(NSString *timeZoneName in array){
[formatter setTimeZone:[NSTimeZone timeZoneWithName:timeZoneName]];
NSLog(@"%@,%@",timeZoneName,[formatter stringFromDate:nowDate]);
}
[formatter release];
[nowDate release];
NSCalendar用法：
-(NSString *) getWeek:(NSDate *) d {
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
unsigned units = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekdayCalendarUnit;
NSDateComponents *components = [calendar components:units fromDate:d];
[calendar release];
switch ([components weekday]) {
case 2:
return @"Monday";
break;
case 3:
return @"Tuesday";
break;
case 4:
return @"Wednesday";
break;
case 5:
return @"Thursday";
break;
case 6:
return @"Friday";
break;
case 7:
return @"Saturday";
break;
case 1:
return @"Sunday";
break;
default:
return @"No Week";
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 *) url {
return [[NSString alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]] encoding:NSUTF8StringEncoding];
}
//读取网络图片
- (UIImage *) getImageByURL:(NSString *) url {
return [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]];
}
多线程（这种方式，只管建立线程，不管回收线程，为什么大家都只会这种方式）
[NSThread detachNewThreadSelector:@selector(scheduleTask) toTarget:self withObject:nil];
-(void) scheduleTask {
//create a pool
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
//release the pool;
[pool release];
}
//如果有参数，则这么使用：//注意这里有个冒号
[NSThread detachNewThreadSelector:@selector(scheduleTask:) toTarget:self withObject:[NSDate date]];
-(void) scheduleTask:(NSDate *) mdate {
//create a pool 这里都重新建立一个内存池！！！
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
//release the pool;
[pool release];
}
//注意selector里有冒号。
//在线程里运行主线程里的方法
[self performSelectorOnMainThread:@selector(moveToMain) withObject:nil waitUntilDone:FALSE];
6. 定时器NSTimer用法:
代码
// 一个可以自动关闭的Alert窗口
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil
message:[@"一个可以自动关闭的Alert窗口"
delegate:nil
cancelButtonTitle:nil //NSLocalizedString(@"OK", @"OK") //取消任何按钮
otherButtonTitles:nil];
//[alert setBounds:CGRectMake(alert.bounds.origin.x, alert.bounds.origin.y, alert.bounds.size.width, alert.bounds.size.height+30.0)];
[alert show];
UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
// Adjust the indicator so it is up a few pixels from the bottom of the alert
indicator.center = CGPointMake(alert.bounds.size.width/2, alert.bounds.size.height-40.0);
[indicator startAnimating];
[alert insertSubview:indicator atIndex:0];
[indicator release];
[NSTimer scheduledTimerWithTimeInterval:3.0f
target:self
selector:@selector(dismissAlert:)
userInfo:[NSDictionary dictionaryWithObjectsAndKeys: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(@"release alert");
[alert release];
-(void) dismissAlert:(NSTimer *)timer{
NSLog(@"release timer");
NSLog([[timer userInfo] objectForKey:@"key"]);
UIAlertView *alert = [[timer userInfo] objectForKey:@"alert"];
[alert dismissWithClickedButtonIndex:0 animated:YES];
}
定时器停止使用：
[timer invalidate];
timer = nil;
7. 用户缺省值NSUserDefaults读取：
//得到用户缺省值
NSUserDefaults *defs = [NSUserDefaults standardUserDefaults];
//在缺省值中找到AppleLanguages, 返回值是一个数组
NSArray* languages = [defs objectForKey:@"AppleLanguages"];
NSLog(@"all language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 %@",[languages objectAtIndex:0]);
//get the language & country code
NSLocale *currentLocale = [NSLocale currentLocale];
NSLog(@"Language Code is %@", [currentLocale objectForKey:NSLocaleLanguageCode]);
NSLog(@"Country Code is %@", [currentLocale objectForKey:NSLocaleCountryCode
8. View之间切换的动态效果设置：//这么简单。。这个类很强大啊
SettingsController *settings = [[SettingsController alloc]initWithNibName:@"SettingsView" bundle:nil];
settings.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal; //水平翻转
[self presentModalViewController:settings animated:YES];
[settings release];
9.NSScrollView 滑动用法：
-(void) scrollViewDidScroll:(UIScrollView *)scrollView{
NSLog(@"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NSScrollView滑动，看不到滑动条
- (void) scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
}
11.键盘处理系列
//set the UIKeyboard to switch to a different text field when you press return
//switch textField to the name of your textfield
[textField becomeFirstResponder];
srandom(time(NULL)); //随机数种子
id d = random(); // 随机数
4. iPhone的系统目录:
//得到Document目录：
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex: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：
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
6.app Icon显示数字：
- (void)applicationDidEnterBackground:(UIApplication *)application{
[[UIApplication sharedApplication] setApplicationIconBadgeNumber:5];
}
7.sqlite保存地址：
代码
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *thePath = [paths objectAtIndex:0];
NSString *filePath = [thePath stringByAppendingPathComponent:@"kilonet1.sqlite"];
NSString *dbPath = [[[NSBundle mainBundle] resourcePath]
stringByAppendingPathComponent:@"kilonet2.sqlite"];
8.Application退出：exit(0);
9. AlertView，ActionSheet的cancelButton点击事件：
代码
-(void) actionSheet UIActionSheet *) actionSheet didDismissWithButtonIndex:(NSInteger) buttonIndex {
NSLog(@"cancel actionSheet........");
//当用户按下cancel按钮
if( buttonIndex == [actionSheet cancelButtonIndex]) {
exit(0);
}
// //当用户按下destructive按钮
// if( buttonIndex == [actionSheet destructiveButtonIndex]) {
// // DoSomething here.
// }
}
- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex {
NSLog(@"cancel alertView........");
if (buttonIndex == [alertView cancelButtonIndex]) {
exit(0);
}
}
10.给Window设置全局的背景图片：
window.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"coolblack.png"]];
11. UITextField文本框显示及对键盘的控制:
代码
#pragma mark -
#pragma mark UITextFieldDelegate
//控制键盘跳转
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
if (textField == _txtAccount) {
if ([_txtAccount.text length]==0) {
return NO;
}
[_txtPassword becomeFirstResponder];
} else if (textField == _txtPassword) {
[_txtPassword resignFirstResponder];
}
return YES;
}
//输入框背景更换
-(BOOL) textFieldShouldBeginEditing:(UITextField *)textField{
[textField setBackground:[UIImage imageNamed:@"ctext_field_02.png"]];
return YES;
}
-(void) textFieldDidEndEditing:(UITextField *)textField{
[textField setBackground:[UIImage imageNamed:@"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
CGRect frame = [_txtAccount frame];
frame.size.width = 5;
UIView *leftview = [[UIView alloc] initWithFrame:frame];
_txtAccount.leftViewMode = UITextFieldViewModeAlways;
_txtAccount.leftView = leftview;
13. UIScrollView 设置滑动不超出本身范围：
[fcScrollView setBounces:NO];
14. 遍历View里面所有的Subview：
代码
NSLog(@"subviews count=%d",[self.view.subviews count]);
if ([self.view.subviews count] > 0) {
for (UIView *curView in self.view.subviews) {
NSLog(@”view.subviews=%@”, [NSString stringWithUTF8String:object_getClassName(curView)]);
}
}
14. 在drawRect里画文字：
UIFont * f = [UIFont systemFontOfSize:20];
[[UIColor darkGrayColor] set];
NSString * text = @”hi \nKiloNet”;
[text drawAtPoint: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 = [string componentsSeparatedByString:@","];
string = [[array valueForKey:@"description"] componentsJoinedByString:@”,”];
17. TabController随意切换tab bar：
[self.tabBarController setSelectedIndex:tabIndex];
或者 self.tabBarController.selectedIndex = tabIndex;
或者实现下面的delegate来扑捉tab bar的事件：
代码-(BOOL) tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController { if ([viewController.tabBarItem.title isEqualToString: NSLocalizedString(@"Logout",nil)]) { [self showLogout]; return NO; } return
YES;}
18. 自定义View之间切换动画：
代码
- (void) pushController: (UIViewController*) controller
withTransition: (UIViewAnimationTransition) transition
{
[UIView beginAnimations:nil context:NULL];
[self pushViewController:controller animated:NO];
[UIView setAnimationDuration:.5];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationTransition:transition forView:self.view cache:YES];
[UIView commitAnimations];
}
CATransition *transition = [CATransition animation];
transition.duration = kAnimationDuration;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionPush;
transition.subtype = kCATransitionFromTop;
transitioning = YES;
transition.delegate = self;
[self.navigationController.view.layer addAnimation:transition forKey:nil];
self.navigationController.navigationBarHidden = NO;
[self.navigationController pushViewController:tableViewController animated:YES];
20.计算字符串长度：
CGFloat w = [title sizeWithFont:[UIFont fontWithName:@"Arial" size:18]].width;
23.在使用UISearchBar时，将背景色设定为clearColor，或者将translucent设为YES，都不能使背景透明，经过一番研究，发现了一种超级简单和实用的方法：
1
[[searchbar.subviews objectAtIndex:0]removeFromSuperview];
背景完全消除了，只剩下搜索框本身了。
24. 图像与缓存 :
UIImageView *wallpaper = [[UIImageView alloc] initWithImage:
[UIImage imageNamed:@"icon.png"]]; // 会缓存图片
UIImageView *wallpaper = [[UIImageView alloc] initWithImage:
[UIImage imageWithContentsOfFile:@"icon.png"]]; // 不会缓存图片
25. iphone-常用的对视图图层(layer)的操作
对图层的操作：
(1.给图层添加背景图片：//这里都是layer的，要研究下layer
myView.layer.contents = (id)[UIImage imageNamed:@"view_BG.png"].CGImage;
(2.将图层的边框设置为圆脚
myWebView.layer.cornerRadius = 8;
myWebView.layer.masksToBounds = YES;
(3.给图层添加一个有色边框
myWebView.layer.borderWidth = 5;
myWebView.layer.borderColor = [[UIColor colorWithRed:0.52 green:0.09 blue:0.07 alpha:1] CGColor];
在写代码的时候很容易被一些那些我们看似简单的问题难住，也严重影响了我们工作的进度，所以今天把一些在iOS中常用 关于类型的转换和常用的用法总结下。
字符的表示含义：
%c 一个单一的字符
%d 一个十进制整数
%i 一个整数 //原来i%是这个区别啊
%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 //也挺特别的
%n 一个等于读取字符数量的整数 //特别的东东
%u 一个无符号整数
%[] 一个字符集 //没见过
%% 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 = @”This is a String!”;
2、创建空字符串，给予赋值。
NSString *astring = [[NSString alloc] init];
astring = @”This is a String!”;
NSLog(@”astring:%@”,astring); //NSLog要这么用？反正当直接使用NSLog(astring)会有警告
[astring release];
3、在以上方法中，提升速度:initWithString方法
NSString *astring = [[NSString alloc] initWithString:@”This is a String!”];
NSLog(@”astring:%@”,astring);
[astring release];
4、用标准c创建字符串:initWithCString方法
char *Cstring = “This is a String!”;
NSString *astring = [[NSString alloc] initWithCString:Cstring];
NSLog(@”astring:%@”,astring);
[astring release];
5、创建格式化字符串:占位符（由一个%加一个字符组成）
int i = 1;
int j = 2;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];
NSLog(@”astring:%@”,astring);
[astring release];
6、创建临时字符串
NSString *astring;
astring = [NSString stringWithCString:"This is a temporary string"];
NSLog(@”astring:%@”,astring);
/*—————-从文件读取字符串:initWithContentsOfFile方法 —————-*/
NSString *path = @”astring.text”;
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@”astring:%@”,astring);
[astring release];
/*—————-写字符串到文件:writeToFile方法 —————-*/
NSString *astring = [[NSString alloc] initWithString:@”This is a String!”];
NSLog(@”astring:%@”,astring);
NSString *path = @”astring.text”;
[astring writeToFile: path atomically: YES];
[astring release];
/*—————- 比较两个字符串—————-*/
用C比较:strcmp函数
char string1[] = “string!”;
char string2[] = “string!”;
if(strcmp(string1, string2) = = 0)
{
NSLog(@”1″);
}
isEqualToString方法
NSString *astring01 = @”This is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 isEqualToString:astring02];
NSLog(@”result:%d”,result);
compare方法(comparer返回的三种值)
NSString *astring01 = @”This is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 compare:astring02] = = NSOrderedSame;
NSLog(@”result:%d”,result);
NSOrderedSame 判断两者内容是否相同
NSString *astring01 = @”This is a String!”;
NSString *astring02 = @”this is a String!”;
BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;
NSLog(@”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 = @”this is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 compare: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1
NSString *astring01 = @”this is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 caseInsensitiveCompare: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2
NSString *astring01 = @”this is a String!”;
NSString *astring02 = @”This is a String!”;
BOOL result = [astring01 compare:astring02
options: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 = @”A String”;
NSString *string2 = @”String”;
NSLog(@”string1:%@”,[string1 uppercaseString]);//大写
NSLog(@”string2:%@”,[string2 lowercaseString]);//小写
NSLog(@”string2:%@”,[string2 capitalizedString]);//首字母大小
/*—————-在串中搜索子串 —————-*/
NSString *string1 = @”This is a string”;
NSString *string2 = @”string”;
NSRange range = [string1 rangeOfString:string2];
int location = range.location;
int leight = range.length;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%i,Leight:%i",location,leight]];
NSLog(@”astring:%@”,astring);
[astring release];
/*—————-抽取子串 —————-*/
-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 = @”This is a string”;
NSString *string2 = [string1 substringToIndex: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
NSString *string1 = @”This is a string”;
NSString *string2 = [string1 substringFromIndex: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串
NSString *string1 = @”This is a string”;
NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];
NSLog(@”string2:%@”,string2);
const char *fieldValue = [value cStringUsingEncoding:NSUTF8StringEncoding];
const char *fieldValue = [value UTF8String];
NSString 转 NSData
NSString* str= @”kilonet”;
NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding];
Date format用法：
-(NSString *) getDay:(NSDate *) d
{
NSString *s ;
NSDateFormatter *format = [[NSDateFormatter alloc] init];
[format setDateFormat:@"YYYY/MM/dd hh:mm:ss"];
s = [format stringFromDate:d];
[format release];
return s;
}
各地时区获取：
代码
NSDate *nowDate = [NSDate new]; //竟然是这个样子，干嘛，四不像。你以为你是c++啊
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy/MM/dd HH: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 = [NSTimeZone timeZoneWithName:@"Europe/Andorra"];
// [formatter setTimeZone:timeZone];
//获取所有的时区名字
NSArray *array = [NSTimeZone knownTimeZoneNames];
// NSLog(@”array:%@”,array);
//for循环
// for(int i=0;i<[array count];i++)
// {
// NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:[array objectAtIndex:i]];
// [formatter setTimeZone:timeZone];
// NSString *locationTime = [formatter stringFromDate:nowDate];
// NSLog(@"时区名字:%@ : 时区当前时间: %@",[array objectAtIndex:i],locationTime);
// //NSLog(@"timezone name is:%@",[array objectAtIndex:i]);
// }
//快速枚举法
for(NSString *timeZoneName in array){
[formatter setTimeZone:[NSTimeZone timeZoneWithName:timeZoneName]];
NSLog(@"%@,%@",timeZoneName,[formatter stringFromDate:nowDate]);
}
[formatter release];
[nowDate release];
NSCalendar用法：
-(NSString *) getWeek:(NSDate *) d {
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
unsigned units = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekdayCalendarUnit;
NSDateComponents *components = [calendar components:units fromDate:d];
[calendar release];
switch ([components weekday]) {
case 2:
return @"Monday";
break;
case 3:
return @"Tuesday";
break;
case 4:
return @"Wednesday";
break;
case 5:
return @"Thursday";
break;
case 6:
return @"Friday";
break;
case 7:
return @"Saturday";
break;
case 1:
return @"Sunday";
break;
default:
return @"No Week";
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 *) url {
return [[NSString alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]] encoding:NSUTF8StringEncoding];
}
//读取网络图片
- (UIImage *) getImageByURL:(NSString *) url {
return [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]];
}
多线程（这种方式，只管建立线程，不管回收线程，为什么大家都只会这种方式）
[NSThread detachNewThreadSelector:@selector(scheduleTask) toTarget:self withObject:nil];
-(void) scheduleTask {
//create a pool
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
//release the pool;
[pool release];
}
//如果有参数，则这么使用：//注意这里有个冒号
[NSThread detachNewThreadSelector:@selector(scheduleTask:) toTarget:self withObject:[NSDate date]];
-(void) scheduleTask:(NSDate *) mdate {
//create a pool 这里都重新建立一个内存池！！！
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
//release the pool;
[pool release];
}
//注意selector里有冒号。
//在线程里运行主线程里的方法
[self performSelectorOnMainThread:@selector(moveToMain) withObject:nil waitUntilDone:FALSE];
6. 定时器NSTimer用法:
代码
// 一个可以自动关闭的Alert窗口
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil
message:[@"一个可以自动关闭的Alert窗口"
delegate:nil
cancelButtonTitle:nil //NSLocalizedString(@"OK", @"OK") //取消任何按钮
otherButtonTitles:nil];
//[alert setBounds:CGRectMake(alert.bounds.origin.x, alert.bounds.origin.y, alert.bounds.size.width, alert.bounds.size.height+30.0)];
[alert show];
UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
// Adjust the indicator so it is up a few pixels from the bottom of the alert
indicator.center = CGPointMake(alert.bounds.size.width/2, alert.bounds.size.height-40.0);
[indicator startAnimating];
[alert insertSubview:indicator atIndex:0];
[indicator release];
[NSTimer scheduledTimerWithTimeInterval:3.0f
target:self
selector:@selector(dismissAlert:)
userInfo:[NSDictionary dictionaryWithObjectsAndKeys: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(@"release alert");
[alert release];
-(void) dismissAlert:(NSTimer *)timer{
NSLog(@"release timer");
NSLog([[timer userInfo] objectForKey:@"key"]);
UIAlertView *alert = [[timer userInfo] objectForKey:@"alert"];
[alert dismissWithClickedButtonIndex:0 animated:YES];
}
定时器停止使用：
[timer invalidate];
timer = nil;
7. 用户缺省值NSUserDefaults读取：
//得到用户缺省值
NSUserDefaults *defs = [NSUserDefaults standardUserDefaults];
//在缺省值中找到AppleLanguages, 返回值是一个数组
NSArray* languages = [defs objectForKey:@"AppleLanguages"];
NSLog(@"all language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 %@",[languages objectAtIndex:0]);
//get the language & country code
NSLocale *currentLocale = [NSLocale currentLocale];
NSLog(@"Language Code is %@", [currentLocale objectForKey:NSLocaleLanguageCode]);
NSLog(@"Country Code is %@", [currentLocale objectForKey:NSLocaleCountryCode
8. View之间切换的动态效果设置：//这么简单。。这个类很强大啊
SettingsController *settings = [[SettingsController alloc]initWithNibName:@"SettingsView" bundle:nil];
settings.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal; //水平翻转
[self presentModalViewController:settings animated:YES];
[settings release];
9.NSScrollView 滑动用法：
-(void) scrollViewDidScroll:(UIScrollView *)scrollView{
NSLog(@"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NSScrollView滑动，看不到滑动条
- (void) scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
}
11.键盘处理系列
//set the UIKeyboard to switch to a different text field when you press return
//switch textField to the name of your textfield
[textField becomeFirstResponder];
srandom(time(NULL)); //随机数种子
id d = random(); // 随机数
4. iPhone的系统目录:
//得到Document目录：
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex: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：
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
6.app Icon显示数字：
- (void)applicationDidEnterBackground:(UIApplication *)application{
[[UIApplication sharedApplication] setApplicationIconBadgeNumber:5];
}
7.sqlite保存地址：
代码
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *thePath = [paths objectAtIndex:0];
NSString *filePath = [thePath stringByAppendingPathComponent:@"kilonet1.sqlite"];
NSString *dbPath = [[[NSBundle mainBundle] resourcePath]
stringByAppendingPathComponent:@"kilonet2.sqlite"];
8.Application退出：exit(0);
9. AlertView，ActionSheet的cancelButton点击事件：
代码
-(void) actionSheet UIActionSheet *) actionSheet didDismissWithButtonIndex:(NSInteger) buttonIndex {
NSLog(@"cancel actionSheet........");
//当用户按下cancel按钮
if( buttonIndex == [actionSheet cancelButtonIndex]) {
exit(0);
}
// //当用户按下destructive按钮
// if( buttonIndex == [actionSheet destructiveButtonIndex]) {
// // DoSomething here.
// }
}
- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex {
NSLog(@"cancel alertView........");
if (buttonIndex == [alertView cancelButtonIndex]) {
exit(0);
}
}
10.给Window设置全局的背景图片：
window.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"coolblack.png"]];
11. UITextField文本框显示及对键盘的控制:
代码
#pragma mark -
#pragma mark UITextFieldDelegate
//控制键盘跳转
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
if (textField == _txtAccount) {
if ([_txtAccount.text length]==0) {
return NO;
}
[_txtPassword becomeFirstResponder];
} else if (textField == _txtPassword) {
[_txtPassword resignFirstResponder];
}
return YES;
}
//输入框背景更换
-(BOOL) textFieldShouldBeginEditing:(UITextField *)textField{
[textField setBackground:[UIImage imageNamed:@"ctext_field_02.png"]];
return YES;
}
-(void) textFieldDidEndEditing:(UITextField *)textField{
[textField setBackground:[UIImage imageNamed:@"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
CGRect frame = [_txtAccount frame];
frame.size.width = 5;
UIView *leftview = [[UIView alloc] initWithFrame:frame];
_txtAccount.leftViewMode = UITextFieldViewModeAlways;
_txtAccount.leftView = leftview;
13. UIScrollView 设置滑动不超出本身范围：
[fcScrollView setBounces:NO];
14. 遍历View里面所有的Subview：
代码
NSLog(@"subviews count=%d",[self.view.subviews count]);
if ([self.view.subviews count] > 0) {
for (UIView *curView in self.view.subviews) {
NSLog(@”view.subviews=%@”, [NSString stringWithUTF8String:object_getClassName(curView)]);
}
}
14. 在drawRect里画文字：
UIFont * f = [UIFont systemFontOfSize:20];
[[UIColor darkGrayColor] set];
NSString * text = @”hi \nKiloNet”;
[text drawAtPoint: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 = [string componentsSeparatedByString:@","];
string = [[array valueForKey:@"description"] componentsJoinedByString:@”,”];
17. TabController随意切换tab bar：
[self.tabBarController setSelectedIndex:tabIndex];
或者 self.tabBarController.selectedIndex = tabIndex;
或者实现下面的delegate来扑捉tab bar的事件：
代码-(BOOL) tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController { if ([viewController.tabBarItem.title isEqualToString: NSLocalizedString(@"Logout",nil)]) { [self showLogout]; return NO; } return
YES;}
18. 自定义View之间切换动画：
代码
- (void) pushController: (UIViewController*) controller
withTransition: (UIViewAnimationTransition) transition
{
[UIView beginAnimations:nil context:NULL];
[self pushViewController:controller animated:NO];
[UIView setAnimationDuration:.5];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationTransition:transition forView:self.view cache:YES];
[UIView commitAnimations];
}
CATransition *transition = [CATransition animation];
transition.duration = kAnimationDuration;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionPush;
transition.subtype = kCATransitionFromTop;
transitioning = YES;
transition.delegate = self;
[self.navigationController.view.layer addAnimation:transition forKey:nil];
self.navigationController.navigationBarHidden = NO;
[self.navigationController pushViewController:tableViewController animated:YES];
20.计算字符串长度：
CGFloat w = [title sizeWithFont:[UIFont fontWithName:@"Arial" size:18]].width;
23.在使用UISearchBar时，将背景色设定为clearColor，或者将translucent设为YES，都不能使背景透明，经过一番研究，发现了一种超级简单和实用的方法：
1
[[searchbar.subviews objectAtIndex:0]removeFromSuperview];
背景完全消除了，只剩下搜索框本身了。
24. 图像与缓存 :
UIImageView *wallpaper = [[UIImageView alloc] initWithImage:
[UIImage imageNamed:@"icon.png"]]; // 会缓存图片
UIImageView *wallpaper = [[UIImageView alloc] initWithImage:
[UIImage imageWithContentsOfFile:@"icon.png"]]; // 不会缓存图片
25. iphone-常用的对视图图层(layer)的操作
对图层的操作：
(1.给图层添加背景图片：//这里都是layer的，要研究下layer
myView.layer.contents = (id)[UIImage imageNamed:@"view_BG.png"].CGImage;
(2.将图层的边框设置为圆脚
myWebView.layer.cornerRadius = 8;
myWebView.layer.masksToBounds = YES;
(3.给图层添加一个有色边框
myWebView.layer.borderWidth = 5;
myWebView.layer.borderColor = [[UIColor colorWithRed:0.52 green:0.09 blue:0.07 alpha:1] CGColor];
内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 
相关文章推荐
- 25条iOS开发中类型的转换和常用的知识点-总结
- 25条iOS开发中类型的转换和常用的知识点-总结
- ios类型转换和25条常用知识点总结
- ios开发常用知识点总结
- IOS开发，知识点小结,ios开发中常用的宏定义总结
- iOS 各种数据类型的转换 和知识点的总结
- ios开发之某些知识点总结
- 总结iOS 开发的几个常用代码
- 学习IOS开发UI篇--UI知识点总结(四) UITabelView/UITableViewCell
- iOS开发(Objective-C)常用库索引（十分有用的总结）
- JavaScript开发中几个常用知识点总结
- ios开发——NSData相关类型转换
- IOS开发时间格式转换之──C语言中time_t数据类型转为NSString类型
- 学习IOS开发UI篇--UI知识点总结(一) UIButton/UITextField
- iOS开发 -- UITableView 完整知识点总结(一)
- JavaScript开发中几个常用知识点总结
- 【无限互联】iOS开发视频教程—2.4iPhone开发之基本数据类型转换
- iOS开发中很重要，很常用，但却容易被忽略的知识点：id ,NSObject, id<NSObject>区别
- Objective-C开发——数据类型知识点总结
- ios开发之某些知识点总结