一些常用的代码片段，提高开发效率
CGImageRef imageRef = image.CGImage;
CGRect rect = CGRectMake(origin.x, origin.y ,size.width, size.height);
CGImageRef imageRefRect = CGImageCreateWithImageInRect(imageRef, rect);
UIImage *imageRect = [[UIImage alloc] initWithCGImage:imageRefRect];
2、判断设备是iphone还是iphone4的代码：
#define isRetina ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 960), [[UIScreen mainScreen] currentMode].size) : NO)
3、判断邮箱输入的是否正确：
- (BOOL) validateEmail: (NSString *) candidate {
NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
return [emailTest evaluateWithObject:candidate];
}
4、如何把当前的视图作为照片保存到相册中去：
#import
UIGraphicsBeginImageContext(currentView.bounds.size); //currentView 当前的view
[currentView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
5、本地通知（类似于push通知）按home键到后台 十秒后触发：
UILocalNotification *notification=[[UILocalNotification alloc] init];
if (notification!=nil) {
NSLog(@">> support local notification");
NSDate *now=[NSDate new];
notification.fireDate=[now addTimeInterval:10];
notification.timeZone=[NSTimeZone defaultTimeZone];
notification.alertBody=@"该去吃晚饭了！";
[[UIApplication sharedApplication].scheduleLocalNotification:notification];
}
6、捕获iphone通话事件：
CTCallCenter *center = [[CTCallCenter alloc] init];
center.callEventHandler = ^(CTCall *call)
{
NSLog(@"call:%@", call.callState);
}
7、iOS 4 引入了多任务支持，所以用户按下 “Home” 键以后程序可能并没有退出而是转入了后台运行。如果您想让应用直接退出，最简单的方法是：在 info－plist 里面找到 Application does not run in background 一项，勾选即可。
8、使UIimageView的图像旋转：
float rotateAngle = M_PI;
CGAffineTransform transform =CGAffineTransformMakeRotation(rotateAngle);
imageView.transform = transform;
9、设置旋转的原点：
#import
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"bg.png"]];
imageView.layer.anchorPoint = CGPointMake(0.5, 1.0);
10、实现自定义的状态栏（遮盖状态栏）：
CGRect frame = {{0, 0}, {320, 20}};
UIWindow* wd = [[UIWindow alloc] initWithFrame:frame];
[wd setBackgroundColor:[UIColor clearColor]];
[wd setWindowLevel:UIWindowLevelStatusBar];
frame = CGRectMake(100, 0, 30, 20);
UIImageView* img = [[UIImageView alloc] initWithFrame:frame];
[img setContentMode:UIViewContentModeCenter];
[img setImage:[UIImage imageNamed:@"00_0103.png"]];
[wd addSubview:img];
[wd makeKeyAndVisible];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2];
frame.origin.x += 150;
[img setFrame:frame];
[UIView commitAnimations];
11、在程序中实现电话的拨打：
//添加电话图标按钮
UIButton *btnPhone = [[UIButton buttonWithType:UIButtonTypeCustom] retain];
btnPhone.frame = CGRectMake(280,10,30,30);
UIImage *image = [UIImage imageNamed:@"phone.png"];
[btnPhone setBackgroundImage:image forState:UIControlStateNormal];
//点击拨号按钮直接拨号
[btnPhone addTarget:self action:@selector(callAction:event:)forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:btnPhone]; //cell是一个UITableViewCell
//定义点击拨号按钮时的操作
- (void)callAction:(id)sender event:(id)event{
NSSet *touches = [event allTouches];
UITouch *touch = [touches anyObject];
CGPoint currentTouchPosition = [touch locationInView:self.listTable];
NSIndexPath *indexPath = [self.listTable indexPathForRowAtPoint: currentTouchPosition];
if (indexPath == nil) {
return;
}
NSInteger section = [indexPath section];
NSUInteger row = [indexPath row];
NSDictionary *rowData = [datas objectAtIndex:row];
NSString *num = [[NSString alloc] initWithFormat:@"tel://%@",number]; //number为号码字符串
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:num]]; //拨号
}
12、更改iphone的键盘颜色：
1.只有这2种数字键盘才有效果。UIKeyboardTypeNumberPad，UIKeyboardTypePhonePad
2. keyboardAppearance ＝ UIKeyboardAppearanceAlert
- (void)textViewDidBeginEditing:(UITextView *)textView{
NSArray *ws = [[UIApplication sharedApplication] windows];
for(UIView *w in ws){
NSArray *vs = [w subviews];
for(UIView *v in vs)
{
if([[NSString stringWithUTF8String:object_getClassName(v)] isEqualToString:@"UIKeyboard"])
{
v.backgroundColor = [UIColor redColor];
}
}
}
13、设置时区
NSTimeZone *defaultTimeZone = [NSTimeZone defaultTimeZone];
NSTimeZone *tzGMT = [NSTimeZone timeZoneWithName:@"GMT"];
[NSTimeZone setDefaultTimeZone:tzGMT];
上面两个时区任意用一个。
14、Ipad隐藏键盘的同时触发方法。
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
- (IBAction)keyboardWillHide:(NSNotification *)note
14、在一个程序中打开另一个程序的方法。
http://www.cocoachina.com/iphonedev/sdk/2010/0322/768.html
15、计算字符串的字数
-(int)calculateTextNumber:(NSString *)text
{
float number = 0.0;
int index = 0;
for (index; index < [text length]; index++)
{
NSString *protoText = [text substringToIndex:[text length] - index];
NSString *toChangetext = [text substringToIndex:[text length] -1 -index];
NSString *charater;
if ([toChangetext length]==0)
{
charater = protoText;
}
else
{
NSRange range = [text rangeOfString:toChangetext];
charater = [protoText stringByReplacingCharactersInRange:range withString:@""];
}
NSLog(charater);
if ([charater lengthOfBytesUsingEncoding:NSUTF8StringEncoding] == 3)
{
number++;
}
else
{
number = number+0.5;
}
}
return ceil(number);
}
转自:http://blog.sina.com.cn/s/blog_6a2cbc930100m7eh.html
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：
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];
转自:http://www.cnblogs.com/tracy-e/archive/2010/10/14/1851035.html
iPhone中的剪切技巧:
1.获取图形上下文
2.构造剪切的路径(形状)
3.构建剪切区域
4.贴上你的画
// 1CGContextRef context = UIGraphicsGetCurrentContext();
// 2CGRect bounds = CGRectMake(0.0f, 0.0f, SIDELENGTH, SIDELENGTH);
CGMutablePathRef path = CGPathCreateMutable();CGPathAddEllipseInRect(path, NULL, bounds);
// 3CGContextAddPath(context, path);CGContextClip(context);
// 4[LOGO drawInRect:bounds];
截取屏幕图片
//创建一个基于位图的图形上下文并指定大小为CGSizeMake(200,400)
UIGraphicsBeginImageContext(CGSizeMake(200,400));
//renderInContext 呈现接受者及其子范围到指定的上下文
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
//返回一个基于当前图形上下文的图片
UIImage *aImage = UIGraphicsGetImageFromCurrentImageContext();
//移除栈顶的基于当前位图的图形上下文
UIGraphicsEndImageContext();
//以png格式返回指定图片的数据
imageData = UIImagePNGRepresentation(aImage);
//获取用户设置的本机号码(4.0以前的系统有效,4.0以后暂时没找到获取方法)
NSString *phoneNumber = [[NSUserDefaults standardUserDefaults] valueForKey:@"SBFormattedPhoneNumber"];
//iphone获取本机电话薄里的电话号码列表
/private/var/mobile/Library/AddressBook/AddressBook.sqlitedb
*****.m文件
#import "NSDate-Helper.h"
@implementation NSDate(Helpers)
/*
* This guy can be a little unreliable and produce unexpected results,
* you're better off using daysAgoAgainstMidnight
*/
//获取年月日如:19871127.
- (NSString *)getFormatYearMonthDay
{
NSString *string = [NSString stringWithFormat:@"%d%02d%02d",[self getYear],[self getMonth],[self getDay]];
return string;
}
//返回当前月一共有几周(可能为4,5,6)
- (int )getWeekNumOfMonth
{
return [[self endOfMonth] getWeekOfYear] - [[self beginningOfMonth] getWeekOfYear] + 1;
}
//该日期是该年的第几周
- (int )getWeekOfYear
{
int i;
int year = [self getYear];
NSDate *date = [self endOfWeek];
for (i = 1;[[date dateAfterDay:-7 * i] getYear] == year;i++)
{
}
return i;
}
//返回day天后的日期(若day为负数,则为|day|天前的日期)
- (NSDate *)dateAfterDay:(int)day
{
NSCalendar *calendar = [NSCalendar currentCalendar];
// Get the weekday component of the current date
// NSDateComponents *weekdayComponents = [calendar components:NSWeekdayCalendarUnit fromDate:self];
NSDateComponents *componentsToAdd = [[NSDateComponents alloc] init];
// to get the end of week for a particular date, add (7 - weekday) days
[componentsToAdd setDay:day];
NSDate *dateAfterDay = [calendar dateByAddingComponents:componentsToAdd toDate:self options:0];
[componentsToAdd release];
return dateAfterDay;
}
//month个月后的日期
- (NSDate *)dateafterMonth:(int)month
{
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *componentsToAdd = [[NSDateComponents alloc] init];
[componentsToAdd setMonth:month];
NSDate *dateAfterMonth = [calendar dateByAddingComponents:componentsToAdd toDate:self options:0];
[componentsToAdd release];
return dateAfterMonth;
}
//获取日
- (NSUInteger)getDay{
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *dayComponents = [calendar components:(NSDayCalendarUnit) fromDate:self];
return [dayComponents day];
}
//获取月
- (NSUInteger)getMonth
{
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *dayComponents = [calendar components:(NSMonthCalendarUnit) fromDate:self];
return [dayComponents month];
}
//获取年
- (NSUInteger)getYear
{
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *dayComponents = [calendar components:(NSYearCalendarUnit) fromDate:self];
return [dayComponents year];
}
//获取小时
- (int )getHour {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;
NSDateComponents *components = [calendar components:unitFlags fromDate:self];
NSInteger hour = [components hour];
return (int)hour;
}
//获取分钟
- (int)getMinute {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;
NSDateComponents *components = [calendar components:unitFlags fromDate:self];
NSInteger minute = [components minute];
return (int)minute;
}
- (int )getHour:(NSDate *)date {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;
NSDateComponents *components = [calendar components:unitFlags fromDate:date];
NSInteger hour = [components hour];
return (int)hour;
}
- (int)getMinute:(NSDate *)date {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSUInteger unitFlags =NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit|NSMinuteCalendarUnit;
NSDateComponents *components = [calendar components:unitFlags fromDate:date];
NSInteger minute = [components minute];
return (int)minute;
}
//在当前日期前几天
- (NSUInteger)daysAgo {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:(NSDayCalendarUnit)
fromDate:self
toDate:[NSDate date]
options:0];
return [components day];
}
//午夜时间距今几天
- (NSUInteger)daysAgoAgainstMidnight {
// get a midnight version of ourself:
NSDateFormatter *mdf = [[NSDateFormatter alloc] init];
[mdf setDateFormat:@"yyyy-MM-dd"];
NSDate *midnight = [mdf dateFromString:[mdf stringFromDate:self]];
[mdf release];
return (int)[midnight timeIntervalSinceNow] / (60*60*24) *-1;
}
- (NSString *)stringDaysAgo {
return [self stringDaysAgoAgainstMidnight:YES];
}
- (NSString *)stringDaysAgoAgainstMidnight:(BOOL)flag {
NSUInteger daysAgo = (flag) ? [self daysAgoAgainstMidnight] : [self daysAgo];
NSString *text = nil;
switch (daysAgo) {
case 0:
text = @"Today";
break;
case 1:
text = @"Yesterday";
break;
default:
text = [NSString stringWithFormat:@"%d days ago", daysAgo];
}
return text;
}
/返回一周的第几天(周末为第一天)
- (NSUInteger)weekday {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *weekdayComponents = [calendar components:(NSWeekdayCalendarUnit) fromDate:self];
return [weekdayComponents weekday];
}
//转为NSString类型的
+ (NSDate *)dateFromString:(NSString *)string {
return [NSDate dateFromString:string withFormat:[NSDate dbFormatString]];
}
+ (NSDate *)dateFromString:(NSString *)string withFormat:(NSString *)format {
NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init];
[inputFormatter setDateFormat:format];
NSDate *date = [inputFormatter dateFromString:string];
[inputFormatter release];
return date;
}
+ (NSString *)stringFromDate:(NSDate *)date withFormat:(NSString *)format {
return [date stringWithFormat:format];
}
+ (NSString *)stringFromDate:(NSDate *)date {
return [date string];
}
+ (NSString *)stringForDisplayFromDate:(NSDate *)date prefixed:(BOOL)prefixed {
/*
* if the date is in today, display 12-hour time with meridian,
* if it is within the last 7 days, display weekday name (Friday)
* if within the calendar year, display as Jan 23
* else display as Nov 11, 2008
*/
NSDate *today = [NSDate date];
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *offsetComponents = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)
fromDate:today];
NSDate *midnight = [calendar dateFromComponents:offsetComponents];
NSDateFormatter *displayFormatter = [[NSDateFormatter alloc] init];
NSString *displayString = nil;
// comparing against midnight
if ([date compare:midnight] == NSOrderedDescending) {
if (prefixed) {
[displayFormatter setDateFormat:@"'at' h:mm a"]; // at 11:30 am
} else {
[displayFormatter setDateFormat:@"h:mm a"]; // 11:30 am
}
} else {
// check if date is within last 7 days
NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
[componentsToSubtract setDay:-7];
NSDate *lastweek = [calendar dateByAddingComponents:componentsToSubtract toDate:today options:0];
[componentsToSubtract release];
if ([date compare:lastweek] == NSOrderedDescending) {
[displayFormatter setDateFormat:@"EEEE"]; // Tuesday
} else {
// check if same calendar year
NSInteger thisYear = [offsetComponents year];
NSDateComponents *dateComponents = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)
fromDate:date];
NSInteger thatYear = [dateComponents year];
if (thatYear >= thisYear) {
[displayFormatter setDateFormat:@"MMM d"];
} else {
[displayFormatter setDateFormat:@"MMM d, yyyy"];
}
}
if (prefixed) {
NSString *dateFormat = [displayFormatter dateFormat];
NSString *prefix = @"'on' ";
[displayFormatter setDateFormat:[prefix stringByAppendingString:dateFormat]];
}
}
// use display formatter to return formatted date string
displayString = [displayFormatter stringFromDate:date];
[displayFormatter release];
return displayString;
}
+ (NSString *)stringForDisplayFromDate:(NSDate *)date {
return [self stringForDisplayFromDate:date prefixed:NO];
}
- (NSString *)stringWithFormat:(NSString *)format {
NSDateFormatter *outputFormatter = [[NSDateFormatter alloc] init];
[outputFormatter setDateFormat:format];
NSString *timestamp_str = [outputFormatter stringFromDate:self];
[outputFormatter release];
return timestamp_str;
}
- (NSString *)string {
return [self stringWithFormat:[NSDate dbFormatString]];
}
- (NSString *)stringWithDateStyle:(NSDateFormatterStyle)dateStyle timeStyle:(NSDateFormatterStyle)timeStyle {
NSDateFormatter *outputFormatter = [[NSDateFormatter alloc] init];
[outputFormatter setDateStyle:dateStyle];
[outputFormatter setTimeStyle:timeStyle];
NSString *outputString = [outputFormatter stringFromDate:self];
[outputFormatter release];
return outputString;
}
//返回周日的的开始时间
- (NSDate *)beginningOfWeek {
// largely borrowed from "Date and Time Programming Guide for Cocoa"
// we'll use the default calendar and hope for the best
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *beginningOfWeek = nil;
BOOL ok = [calendar rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek
interval:NULL forDate:self];
if (ok) {
return beginningOfWeek;
}
// couldn't calc via range, so try to grab Sunday, assuming gregorian style
// Get the weekday component of the current date
NSDateComponents *weekdayComponents = [calendar components:NSWeekdayCalendarUnit fromDate:self];
/*
Create a date components to represent the number of days to subtract from the current date.
The weekday value for Sunday in the Gregorian calendar is 1, so subtract 1 from the number of days to subtract from the date in question. (If today's Sunday, subtract 0 days.)
*/
NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
[componentsToSubtract setDay: 0 - ([weekdayComponents weekday] - 1)];
beginningOfWeek = nil;
beginningOfWeek = [calendar dateByAddingComponents:componentsToSubtract toDate:self options:0];
[componentsToSubtract release];
//normalize to midnight, extract the year, month, and day components and create a new date from those components.
NSDateComponents *components = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit)
fromDate:beginningOfWeek];
return [calendar dateFromComponents:components];
}
//返回当前天的年月日.
- (NSDate *)beginningOfDay {
NSCalendar *calendar = [NSCalendar currentCalendar];
// Get the weekday component of the current date
NSDateComponents *components = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit |NSDayCalendarUnit)
fromDate:self];
return [calendar dateFromComponents:components];
}
//返回该月的第一天
- (NSDate *)beginningOfMonth
{
return [self dateAfterDay:-[self getDay] + 1];
}
//该月的最后一天
- (NSDate *)endOfMonth
{
return [[[self beginningOfMonth] dateafterMonth:1] dateAfterDay:-1];
}
//返回当前周的周末
- (NSDate *)endOfWeek {
NSCalendar *calendar = [NSCalendar currentCalendar];
// Get the weekday component of the current date
NSDateComponents *weekdayComponents = [calendar components:NSWeekdayCalendarUnit fromDate:self];
NSDateComponents *componentsToAdd = [[NSDateComponents alloc] init];
// to get the end of week for a particular date, add (7 - weekday) days
[componentsToAdd setDay:(7 - [weekdayComponents weekday])];
NSDate *endOfWeek = [calendar dateByAddingComponents:componentsToAdd toDate:self options:0];
[componentsToAdd release];
return endOfWeek;
}
+ (NSString *)dateFormatString {
return @"yyyy-MM-dd";
}
+ (NSString *)timeFormatString {
return @"HH:mm:ss";
}
+ (NSString *)timestampFormatString {
return @"yyyy-MM-dd HH:mm:ss";
}
// preserving for compatibility
+ (NSString *)dbFormatString {
return [NSDate timestampFormatString];
}
@end
NSArray *sortedArray = [array sortedArrayUsingComparator: ^(id obj1, id obj2) {
if ([obj1 integerValue] > [obj2 integerValue]) {
return (NSComparisonResult)NSOrderedDescending;
}
if ([obj1 integerValue] < [obj2 integerValue]) {
return (NSComparisonResult)NSOrderedAscending;
}
return (NSComparisonResult)NSOrderedSame;
}];
以前只用过[array sortedArrayUsingSelector:@selector(compare:)];方法,若没有现成的compare:方法还要自己写一个新的比较方法,比较麻烦.
在研究对数组逆向排序时看到了这个方法,貌似是4.0新出的blocks.(Block, 简单的说，就是一个函数对象，和其它类型的对象一样，你可以创建它，可以赋给一个变量，也可以作为函数的参数来传递)
blocks传送门:http://www.cocoachina.com/macdev/objc/2010/0601/1591.html
用法:若sortedArray存的数据是Person类的对象,(name,age,address...),要以age排序,即将上面方法中的[obj1 intergerValue] 改为[obj1/2 age]即可;或 要倒序排列,则将NSOrderedDescending和NSOrderedAscending调换.
转自：http://www.cnblogs.com/gushuo/archive/2010/11/16.html