iOS开发的22个诡异技巧

iOS开发的22个诡异技巧结合自身的实践开发经验总结出了22个iOS开发的小技巧，以非常欢乐的语调轻松解决开发过程中所遇到的各种苦逼难题，光读着便已忍俊不禁。1.TableView不显示没内容的Cell怎么办？类似于图1，我不想让下面的那些空显示。很简单，添加“=[[UIViewalloc]init];〞试过都说好，加完这句之后就变成了图2的样子。2.自定义了leftBarbuttonItem左滑返回手势失效了怎么办？self.navigationItem.leftBarButtonItem

=

[[UIBarButtonItem

alloc]

initWithImage:imgstyle:UIBarButtonItemStylePlaintarget:selfaction:@selector(onBack:)];

self.navigationCeractivePopGestureRecognizer.delegate

=

(id<UIGestureRecognizerDelegate>)self;

3.ScrollView莫名其妙不能在viewController划到顶怎么办？self.automaticallyAdjustsScrollViewInsets

=

NO;

4.键盘事件写得好烦躁，都想摔键盘了怎么办？买个结实的键盘；使用IQKeyboardManager〔GitHub上可搜索〕，用完之后腰也不疼了，腿也不酸了。5.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上搬运吧。6.怎么在不新建一个Cell的情况下调整separaLine的位置？_myTableView.separatorInset

=

UIEdgeInsetsMake(0,

100,

0,

0);

7.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.viewendEditing:YES];

}

8.怎么给每个ViewController设定默认的背景图片？使用基类啊，少年。9.想在代码里改在xib里添加的layoutAttributes，但该怎么用代码找？像拉Button一样地拉你的约束，nslayoutattribute也是可以拉线的。10.怎么像Safari一样滑动的时候隐藏navigationbar？navigationController.hidesBarsOnSwipe

=

Yes

11.导航条返回键带的title太讨厌了，怎么让它消失？[[UIBarButtonItem

appearance]

setBackButtonTitlePositionAdjustment:UIOffsetMake(0,

-60)

forBarMetrics:UIBarMetricsDefault];

12.CoreData用起来好烦，语法又臭又长怎么办？MagicRecord13.CollectionView怎么实现tableview那种悬停的header？CSStickyHeaderFlowLayout14.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)

{

caseUIGestureRecognizerStateBegan:

{

if

(direction

==

UIPanGestureRecognizerDirectionUndefined)

{

CGPoint

velocity

=

[sender

velocityInView:recognizer.view];

BOOL

isVerticalGesture

=

fabs(velocity.y)

>

fabs(velocity.x);

if

(isVerticalGesture)

{

if

(velocity.y

>

0)

{

direction

=

UIPanGestureRecognizerDirectionDown;

}

else

{

direction

=

UIPanGestureRecognizerDirectionUp;

}

}

else

{

if

(velocity.x

>

0)

{

direction

=

UIPanGestureRecognizerDirectionRight;

}

else

{

direction

=

UIPanGestureRecognizerDirectionLeft;

}

}

}

break;

}

caseUIGestureRecognizerStateChanged:

{

switch

(direction)

{

caseUIPanGestureRecognizerDirectionUp:

{

[self

handleUpwardsGesture:sender];

break;

}

caseUIPanGestureRecognizerDirectionDown:

{

[self

handleDownwardsGesture:sender];

break;

}

caseUIPanGestureRecognizerDirectionLeft:

{

[self

handleLeftGesture:sender];

break;

}

caseUIPanGestureRecognizerDirectionRight:

{

[self

handleRightGesture:sender];

break;

}

default:

{

break;

}

}

break;

}

caseUIGestureRecognizerStateEnded:

{

direction

=

UIPanGestureRecognizerDirectionUndefined;

break;

}

default:

break;

}

}

15.拉伸图片的时候怎么才能让图片不变形？方法一：UIImage

*image

=

[[UIImage

imageNamed:@"xxx"]

stretchableImageWithLeftCapWidth:10

topCapHeight:10];

注：有开发者提醒这个已经弃用，现在的方法叫resizableImageWithCapInsets。方法二，如图：16.怎么播放GIF的时候这么卡，有没有好点的库？FlipBoard出品的FLAnimatedImage太适合你了。17.怎么一句话添加上拉刷新？使用SVPullToRefresh库：[tableViewaddPullToRefreshWithActionHandler:^{

//

prepend

data

to

dataSource,

insert

cells

at

top

of

table

view//

call

[tableView.pullToRefreshViewstopAnimating]

when

done}

position:SVPullToRefreshPositionBottom];

18.怎么把tableview里Cell的小对勾颜色改成别的颜色？_mTableView.tintColor

=

[UIColorredColor];

19.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];

}

20.怎么把我的navigationbar弄成透明的而不是带模糊的效果？[self.navigationBarsetBackgroundImage:[UIImagenew]

forBarMetrics:UIBarMetricsDefault];

=

[UIImagenew];

=

YES;

21.怎么改变uitextfieldplaceholder的颜色和位置？继承uitextfield，重写这个方法：-

(void)

drawPlaceholderInRect:(CG