iOS开发的一些奇巧淫技

TableView不显示没内容的Cell怎么办?

类似这种,我不想让下面那些空的显示.

很简单.

 self.tableView.tableFooterView = [[UIView alloc] init];

试过的都说好.

加完这句之后就变成了这样.

自定义了leftBarbuttonItem左滑返回手势失效了怎么办?

 self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
                                          initWithImage:img
                                          style:UIBarButtonItemStylePlain
                                          target:self
                                          action:@selector(onBack:)];
 self.navigationController.interactivePopGestureRecognizer.delegate = (id)self;

 

ScrollView莫名其妙不能在viewController划到顶怎么办?

 self.automaticallyAdjustsScrollViewInsets = NO;

 

键盘事件写的好烦躁,都想摔键盘了,怎么办?

1.买个结实的键盘.

2.使用IQKeyboardManager(github上可搜索),用完之后腰也不疼了,腿也不酸了.

为什么我的app老是不流畅,到底哪里出了问题?

如图

这个神器叫做:KMCGeigerCounter,快去github搬运吧.

怎么在不新建一个Cell的情况下调整separaLine的位置?

 _myTableView.separatorInset = UIEdgeInsetsMake(, , , );

 

怎么点击self.view就让键盘收起,需要添加一个tapGestures么?

 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
 {
    [self.view endEditing:YES];
 }

 

怎么给每个ViewController设定默认的背景图片?

使用基类啊,少年。

想在代码里改在xib里添加的layoutAttributes,但是怎么用代码找啊?

像拉button一样的拉你的约束.nslayoutattribute也是可以拉线的.

怎么像safari一样滑动的时候隐藏navigationbar?

 navigationController.hidesBarsOnSwipe = Yes

 

导航条返回键带的title太讨厌了,怎么让它消失!

 [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(, -)
                                                      forBarMetrics:UIBarMetricsDefault];

 

CoreData用起来好烦,语法又臭又长,怎么办?

MagicRecord

CollectionView 怎么实现tableview那种悬停的header?

CSStickyHeaderFlowLayou

能不能只用一个pan手势来代替UISwipegesture的各个方向?

 - (void)pan:(UIPanGestureRecognizer *)sender
 {
 typedef NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) {
     UIPanGestureRecognizerDirectionUndefined,
     UIPanGestureRecognizerDirectionUp,
     UIPanGestureRecognizerDirectionDown,
     UIPanGestureRecognizerDirectionLeft,
     UIPanGestureRecognizerDirectionRight
 };
 static UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined;
 switch (sender.state) {
     case UIGestureRecognizerStateBegan: {
         if (direction == UIPanGestureRecognizerDirectionUndefined) {
             CGPoint velocity = [sender velocityInView:recognizer.view];
             BOOL isVerticalGesture = fabs(velocity.y) > fabs(velocity.x);
             if (isVerticalGesture) {
                 if (velocity.y > ) {
                     direction = UIPanGestureRecognizerDirectionDown;
                 } else {
                     direction = UIPanGestureRecognizerDirectionUp;
                 }
             }
             else {
                 if (velocity.x > ) {
                     direction = UIPanGestureRecognizerDirectionRight;
                 } else {
                     direction = UIPanGestureRecognizerDirectionLeft;
                 }
             }
         }
         break;
     }
     case UIGestureRecognizerStateChanged: {
         switch (direction) {
             case UIPanGestureRecognizerDirectionUp: {
                 [self handleUpwardsGesture:sender];
                 break;
             }
             case UIPanGestureRecognizerDirectionDown: {
                 [self handleDownwardsGesture:sender];
                 break;
             }
             case UIPanGestureRecognizerDirectionLeft: {
                 [self handleLeftGesture:sender];
                 break;
             }
             case UIPanGestureRecognizerDirectionRight: {
                 [self handleRightGesture:sender];
                 break;
             }
             default: {
                 break;
             }
         }
         break;
     }
     case UIGestureRecognizerStateEnded: {
         direction = UIPanGestureRecognizerDirectionUndefined;
         break;
     }
     default:
         break;
 }
 }

 

拉伸图片的时候怎么才能让图片不变形？
1.UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];

2.

怎么播放GIF的时候这么卡，有没有好点的库？

FlipBoard出品的太适合你了：https://github.com/Flipboard/FLAnimatedImage

怎么一句话添加上拉刷新？

https://github.com/samvermette/SVPullToRefresh

 [tableView addPullToRefreshWithActionHandler:^{
 // prepend data to dataSource, insert cells at top of table view
 // call [tableView.pullToRefreshView stopAnimating] when done
 } position:SVPullToRefreshPositionBottom];

 

怎么把tableview里cell的小对勾的颜色改成别的颜色？

 _mTableView.tintColor = [UIColor redColor];

 

本来我的statusbar是lightcontent的，结果用UIImagePickerController会导致我的statusbar的样式变成黑色，怎么办？

 - (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
 {
     [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
 }

 

怎么把我的navigationbar弄成透明的而不是带模糊的效果？

 [self.navigationBar setBackgroundImage:[UIImage new]
                          forBarMetrics:UIBarMetricsDefault];
 self.navigationBar.shadowImage = [UIImage new];
 self.navigationBar.translucent = YES;

 

怎么改变uitextfield placeholder的颜色和位置？

继承uitextfield，重写这个方法

 - (void) drawPlaceholderInRect:(CGRect)rect {
     [[UIColor blueColor] setFill];
     [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
 }

 

你为什么知道这么多奇怪的花招？

去stackoverflow刷问题啊，少年！

原文地址：http://www.cocoachina.com/ios/20141231/10783.html