11.拖到视频进度与滑动手势冲突解决办法
#pragma mark UIGestureRecognizerDelegate
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
UIView *touchView = touch.view;
if ([touchView isKindOfClass:[UISlider class]])
{
return NO;
}
else
{
return YES;
}
}
12.NSDate 与 NSString 转换
1、将字符串 “Fri Nov 11 09:06:27 +0800 2011” 转换成Date：
NSDateFormatter *format = [[NSDateFormatter alloc] init];
NSLocale *enLocale = [[NSLocale alloc] initWithLocaleIdentifier:@"en-US"];
[format setLocale:enLocale];
[enLocale release];
[format setDateFormat:@"EEE MMM dd HH:mm:ss ZZZ yyyy"];
NSDate *dateTime = [format dateFromString:message];
将Date转换成字符串：
NSDate *date = [NSDate date];
NSString * dateString = [format stringFromDate:date];
//字符串转换成NSDate 需要设置NSLocale 否则真机上会失败。
2、获取当前时间，转化成字符串
NSDateFormatter * formatter = [[NSDateFormatteralloc]init];
formatter.dateStyle = NSDateFormatterMediumStyle;
formatter.timeStyle = NSDateFormatterMediumStyle;
formatter.locale = [NSLocalecurrentLocale];
self.timeLabel.text = [formatterstringFromDate:[NSDatedate]];
3、获取月、日、年、时、分、秒
NSDateFormatter *formatter =[[[NSDateFormatteralloc] init] autorelease];
formatter.dateStyle = NSDateFormatterMediumStyle;
formatter.timeStyle = NSDateFormatterMediumStyle;
formatter.locale = [NSLocalecurrentLocale];
NSDate *date = [NSDatedate];
[formatter setTimeStyle:NSDateFormatterMediumStyle];
NSCalendar *calendar = [[[NSCalendaralloc] initWithCalendarIdentifier:NSGregorianCalendar]autorelease];
NSDateComponents *comps = [[[NSDateComponentsalloc] init] autorelease];
NSInteger unitFlags = NSYearCalendarUnit |
NSMonthCalendarUnit |
NSDayCalendarUnit |
NSWeekdayCalendarUnit |
NSHourCalendarUnit |
NSMinuteCalendarUnit |
NSSecondCalendarUnit;
//int week=0;
comps = [calendar components:unitFlags fromDate:date];
int week = [comps weekday];
int year=[comps year];
int month = [comps month];
int day = [comps day];
[formatter setDateStyle:NSDateFormatterMediumStyle];
// //This sets the label with the updated time.
int hour = [comps hour];
int min = [comps minute];
int sec = [comps second];
NSLog(@"day%d",day);
NSLog(@"hour%d",hour);
NSLog(@"min%d",min);
NSLog(@"sec%d",sec);
13.数组中存储数据查询
NSMutableDictionary *userDic1 = [NSMutableDictionary dictionaryWithCapacity:10];
NSMutableDictionary *userDic2 = [NSMutableDictionary dictionaryWithCapacity:10];
[userDic1 setValue:@"Li" forKey:@"name"];
[userDic2 setValue:@"Wang" forKey:@"name"];
NSArray *userArray = [NSArray arrayWithObjects:userDic1,userDic2,nil];
NSPredicate *namePredicate = [NSPredicate predicateWithFormat:@"SELF.name contains[cd] %@ ",@"L"];
NSMutableArray *searchArray = [NSMutableArray arrayWithArray:[userArray filteredArrayUsingPredicate:namePredicate]];
NSLog(@"searchArray == %@",searchArray);
14.自定义拷贝、粘贴窗口
（1）、重写canBecomeFirstResponder方法
- (BOOL)canBecomeFirstResponder{
[super canBecomeFirstResponder];
return YES;
}
（2）、创建自定义UIMenuController
UIMenuItem *share = [[UIMenuItem alloc] initWithTitle:@"分享" action:@selector(share:)];
UIMenuItem *email = [[UIMenuItem alloc] initWithTitle:@"邮件" action:@selector(email:)];
UIMenuItem *print = [[UIMenuItem alloc] initWithTitle:@"打印" action:@selector(print:)];
UIMenuController *menu = [UIMenuController sharedMenuController];
[menu setMenuItems:[NSArray arrayWithObjects:share, email,print, nil]];
[menu setTargetRect:self.frame inView:self.superview];
[menu setMenuVisible:YES animated:YES];
（3）、判断显示哪个menu
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
[super canPerformAction:action withSender:sender];
if ( action == @selector(share:) || action == @selector(email:) || action == @selector(print:))
{
return YES;
}
else
{
return NO;
}
}
15.iOS本地推送通知方法
可在应用后台执行时，本地弹出推送通知，也可以定时触发推送。
- (void)applicationDidEnterBackground:(UIApplication *)application
{
UIDevice* device = [UIDevice currentDevice];
BOOL backgroundSupported = NO;
if ([device respondsToSelector:@selector(isMultitaskingSupported)])
{
backgroundSupported = device.multitaskingSupported;
}
if (backgroundSupported && _bgTask==UIBackgroundTaskInvalid)
{
UIApplication *app = [UIApplication sharedApplication];
_bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
}];
dispatch_async(dispatch_get_main_queue(), ^{
while (app.applicationState==UIApplicationStateBackground && _bgTask!=UIBackgroundTaskInvalid && [app backgroundTimeRemaining] > 10)
{
[NSThread sleepForTimeInterval:1];
NSLog(@"background task %d left left time %d.", _bgTask, (int)[app backgroundTimeRemaining]);
if ([app backgroundTimeRemaining] < 580)
{
UILocalNotification *localNotif = [[UILocalNotification alloc] init];
if (localNotif)
{
localNotif.alertBody = [NSString stringWithString:@"测试本地通知消息，后台提示功能。"];
localNotif.alertAction = NSLocalizedString(@"查看", nil);
localNotif.soundName = UILocalNotificationDefaultSoundName;
localNotif.applicationIconBadgeNumber = 1;
[application presentLocalNotificationNow:localNotif];
[localNotif release];
break;
}
}
}
NSLog(@"background task %d finished.", _bgTask);
[app endBackgroundTask:_bgTask];
_bgTask = UIBackgroundTaskInvalid;
});
}
}
16.动态获取UILabel的高度和宽度
在使用UILabel存放字符串时，经常需要获取label的长宽数据，本文列出了部分常用的计算方法。
1.获取宽度，获取字符串不折行单行显示时所需要的长度
CGSize titleSize = [aString sizeWithFont:font constrainedToSize:CGSizeMake(MAXFLOAT, 30)];
注：如果想得到宽度的话，size的width应该设为MAXFLOAT。
2.获取高度，获取字符串在指定的size内(宽度超过label的宽度则换行)所需的实际高度.
CGSize titleSize = [aString sizeWithFont:font constrainedToSize:CGSizeMake(label.frame.size.width, MAXFLOAT) lineBreakMode:UILineBreakModeWordWrap];
注：如果想得到高度的话，size的height应该设为MAXFLOAT。
3.实际编程时，有时需要计算一段文字最后一个字符的位置，并在其后添加图片或其他控件（如info图标），下面代码为计算label中最后一个字符后面一位的位置的方法。
CGSize sz = [label.text sizeWithFont:label.font constrainedToSize:CGSizeMake(MAXFLOAT, 40)];
CGSize linesSz = [label.text sizeWithFont:label.font constrainedToSize:CGSizeMake(label.frame.size.width, MAXFLOAT) lineBreakMode:UILineBreakModeWordWrap];
if(sz.width <= linesSz.width) //判断是否折行
{
lastPoint = CGPointMake(label.frame.origin.x + sz.width, label.frame.origin.y);
}
else
{
lastPoint = CGPointMake(label.frame.origin.x + (int)sz.width % (int)linesSz.width,linesSz.height - sz.height);
}