1、隱藏導航欄的正確姿勢
套路一:在
viewWillAppear和viewWillDisappear方法里面用動畫方式設置是否隱藏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：設置self為導航控制器的代理，實現(xiàn)代理方法,在將要顯示控制器中設置導航欄隱藏和顯示,使用這種方式不僅完美切合滑動返回手勢,同時也解決了切換tabBar的時候,導航欄動態(tài)隱藏的問題.
- (void)viewDidLoad {
[super viewDidLoad]; // 設置導航控制器的代理為
self self.navigationController.delegate = self;
}
#pragma mark - UINavigationControllerDelegate// 將要顯示控制器
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
// 判斷要顯示的控制器是否是自己
BOOL isShowHomePage = [viewController isKindOfClass:[self class]];
[self.navigationController setNavigationBarHidden:isShowHomePage animated:YES];
}
2、設置圖片的圓角
設置圓角，我們也許會這么做
self.iconImage.layer.masksToBounds = YES;
self.iconImage.layer.cornerRadius = 20;
如果只是設置一張圖片的話，這樣的設置對內存沒什么大影響，如果是在一個TableView里面的，每個cell都有這樣的圓角設置，就會因為使用圖層過量而造成卡頓現(xiàn)象！
可用以下套路避免卡頓，可把這個方法單獨放到分類中使用
- (UIImage *)cutCircleImage {
UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0);
// 獲取上下文
CGContextRef ctr = UIGraphicsGetCurrentContext();
// 設置圓形
CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
CGContextAddEllipseInRect(ctr, rect);
// 裁剪
CGContextClip(ctr);
// 將圖片畫上去
[self drawInRect:rect];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
3、以當前時間為基準進行時間的增減
以當前時間為基準進行時間的增減
* 增減時間（以當前時間為基準）
*
* @param year 1為1年以后的日期 -1為年之前的日期 0為今年
* @param month 1為1個月以后的日期 -1為一個月之前的日期 0為本月
* @param day 1為1天以后的日期 -1為一天之前的日期 0為今天
*
* @return 時間字符串
*/
+(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、跳轉到系統(tǒng)應用的URL
通過
[[UIApplication sharedApplication] openURL:url]來實現(xiàn)跳轉系統(tǒng)的應用
NSURL *url = [NSURL URLWithString:UIApplicationOpenSettingsURLString]; if ([[UIApplication sharedApplication] canOpenURL:url])
{
[[UIApplication sharedApplication] openURL:url];
}
常用的跳轉URL還有以下
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相關：
自定義layout的三個步驟(流水布局)：
一、準備數(shù)據(jù),并保存到布局對象數(shù)組
- (void)prepareLayout{
[super prepareLayout];
//準備item的數(shù)據(jù)
//定義數(shù)組用來保存每個item的frame
NSMutableArray* marr = [NSMutableArray array];
//給每個item布局
for (int i = 0; i < self.clothesInfos.count; i ++) {
//創(chuàng)建布局對象
NSIndexPath* indexPath = [NSIndexPath indexPathForRow:i inSection:0];
UICollectionViewLayoutAttributes* attr = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
//取出數(shù)據(jù)
ClothesModel* model = self.clothesInfos[i];
//計算frame
attr.frame = CGRectMake(itemX, itemY, itemWidth, itemHeight); //保存數(shù)據(jù) [marr addObject:attr];
}
//計算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];
// 把數(shù)據(jù)保存到布局數(shù)組
self.layoutAttributeMarr = marr;
}
二、計算內容區(qū)域
- (CGSize)collectionViewContentSize{
CGFloat CVCWidth = [UIScreen mainScreen].bounds.size.width; UICollectionViewLayoutAttributes* lastAtt = self.layoutAttributeMarr.lastObject;
CGFloat CVCHeight = CGRectGetMaxY(lastAtt.frame)+_margin;
//根據(jù)最大的Y值得到布局內容的高度
CGSize CVCSize = CGSizeMake(CVCWidth, CVCHeight); return CVCSize;
}
三、返回布局對象數(shù)組
- (NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect{
return self.layoutAttributeMarr;
}
