1、隐藏导航栏的正确姿势
套路一:在
viewWillAppear和viewWillDisappear方法里面用动画方式设置是否隐藏NavigationBar
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.navigationController setNavigationBarHidden:YES animated:YES];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[self.navigationController setNavigationBarHidden:NO animated:YES];
}
套路二：设置self为导航控制器的代理，实现代理方法,在将要显示控制器中设置导航栏隐藏和显示,使用这种方式不仅完美切合滑动返回手势,同时也解决了切换tabBar的时候,导航栏动态隐藏的问题.
- (void)viewDidLoad {
[super viewDidLoad]; // 设置导航控制器的代理为
self self.navigationController.delegate = self;
}
#pragma mark - UINavigationControllerDelegate// 将要显示控制器
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
// 判断要显示的控制器是否是自己
BOOL isShowHomePage = [viewController isKindOfClass:[self class]];
[self.navigationController setNavigationBarHidden:isShowHomePage animated:YES];
}
2、设置图片的圆角
设置圆角，我们也许会这么做
self.iconImage.layer.masksToBounds = YES;
self.iconImage.layer.cornerRadius = 20;
如果只是设置一张图片的话，这样的设置对内存没什么大影响，如果是在一个TableView里面的，每个cell都有这样的圆角设置，就会因为使用图层过量而造成卡顿现象！
可用以下套路避免卡顿，可把这个方法单独放到分类中使用
- (UIImage *)cutCircleImage {
UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0);
// 获取上下文
CGContextRef ctr = UIGraphicsGetCurrentContext();
// 设置圆形
CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
CGContextAddEllipseInRect(ctr, rect);
// 裁剪
CGContextClip(ctr);
// 将图片画上去
[self drawInRect:rect];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
3、以当前时间为基准进行时间的增减
以当前时间为基准进行时间的增减
* 增减时间（以当前时间为基准）
*
* @param year 1为1年以后的日期 -1为年之前的日期 0为今年
* @param month 1为1个月以后的日期 -1为一个月之前的日期 0为本月
* @param day 1为1天以后的日期 -1为一天之前的日期 0为今天
*
* @return 时间字符串
*/
+(NSString*)getPastORFutureDateWithYear:(int)year month:(int)month day:(int)day
{
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *comps = nil;
comps = [calendar components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:[NSDate date]];
NSDateComponents *adcomps = [[NSDateComponents alloc] init];
[adcomps setYear:year];
[adcomps setMonth:month];
[adcomps setDay:day];
NSDate *newdate = [calendar dateByAddingComponents:adcomps toDate:[NSDate date] options:0];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy-MM-dd"];
NSTimeZone* timeZone = [NSTimeZone timeZoneWithName:@"Asia/beijing"];
[formatter setTimeZone:timeZone];
NSString *dateFromData = [formatter stringFromDate:newdate];
return dateFromData;
}
4、跳转到系统应用的URL
通过
[[UIApplication sharedApplication] openURL:url]来实现跳转系统的应用
NSURL *url = [NSURL URLWithString:UIApplicationOpenSettingsURLString]; if ([[UIApplication sharedApplication] canOpenURL:url])
{
[[UIApplication sharedApplication] openURL:url];
}
常用的跳转URL还有以下
About — prefs:root=General&path=About Accessibility — prefs:root=General&path=ACCESSIBILITY AirplaneModeOn— prefs:root=AIRPLANE_MODE Auto-Lock — prefs:root=General&path=AUTOLOCK Brightness — prefs:root=Brightness Bluetooth — prefs:root=General&path=Bluetooth Date& Time — prefs:root=General&path=DATE_AND_TIME FaceTime — prefs:root=FACETIME General— prefs:root=General Keyboard — prefs:root=General&path=Keyboard iCloud — prefs:root=CASTLE iCloud Storage & Backup — prefs:root=CASTLE&path=STORAGE_AND_BACKUP International — prefs:root=General&path=INTERNATIONAL Location Services — prefs:root=LOCATION_SERVICES Music — prefs:root=MUSIC Music Equalizer — prefs:root=MUSIC&path=EQ Music VolumeLimit— prefs:root=MUSIC&path=VolumeLimit Network — prefs:root=General&path=Network Nike + iPod — prefs:root=NIKE_PLUS_IPOD Notes — prefs:root=NOTES Notification — prefs:root=NOTIFICATIONS_ID Phone — prefs:root=Phone Photos — prefs:root=Photos Profile — prefs:root=General&path=ManagedConfigurationList Reset — prefs:root=General&path=Reset Safari — prefs:root=Safari Siri — prefs:root=General&path=Assistant Sounds — prefs:root=Sounds SoftwareUpdate— prefs:root=General&path=SOFTWARE_UPDATE_LINK Store — prefs:root=STORE Twitter — prefs:root=TWITTER Usage — prefs:root=General&path=USAGE VPN — prefs:root=General&path=Network/VPN Wallpaper — prefs:root=Wallpaper Wi-Fi — prefs:root=WIFI Setting—prefs:root=INTERNET_TETHERING
5、CollectionView相关：
自定义layout的三个步骤(流水布局)：
一、准备数据,并保存到布局对象数组
- (void)prepareLayout{
[super prepareLayout];
//准备item的数据
//定义数组用来保存每个item的frame
NSMutableArray* marr = [NSMutableArray array];
//给每个item布局
for (int i = 0; i < self.clothesInfos.count; i ++) {
//创建布局对象
NSIndexPath* indexPath = [NSIndexPath indexPathForRow:i inSection:0];
UICollectionViewLayoutAttributes* attr = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
//取出数据
ClothesModel* model = self.clothesInfos[i];
//计算frame
attr.frame = CGRectMake(itemX, itemY, itemWidth, itemHeight); //保存数据 [marr addObject:attr];
}
//计算footView的frame
NSIndexPath* footPath = [NSIndexPath indexPathForRow:0 inSection:0];
UICollectionViewLayoutAttributes* footAtt = [UICollectionViewLayoutAttributes layoutAttributesForSupplementaryViewOfKind:UICollectionElementKindSectionFooter withIndexPath:footPath];
footAtt.frame = CGRectMake(footX, footY, footW, footH);
[marr addObject:footAtt];
// 把数据保存到布局数组
self.layoutAttributeMarr = marr;
}
二、计算内容区域
- (CGSize)collectionViewContentSize{
CGFloat CVCWidth = [UIScreen mainScreen].bounds.size.width; UICollectionViewLayoutAttributes* lastAtt = self.layoutAttributeMarr.lastObject;
CGFloat CVCHeight = CGRectGetMaxY(lastAtt.frame)+_margin;
//根据最大的Y值得到布局内容的高度
CGSize CVCSize = CGSizeMake(CVCWidth, CVCHeight); return CVCSize;
}
三、返回布局对象数组
- (NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect{
return self.layoutAttributeMarr;
}
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