iOS開(kāi)發(fā)的22個(gè)詭異技巧

iOS開(kāi)發(fā)的22個(gè)詭異技巧結(jié)合自身的實(shí)踐開(kāi)發(fā)經(jīng)驗(yàn)總結(jié)出了22個(gè)iOS開(kāi)發(fā)的小技巧，以非常歡樂(lè)的語(yǔ)調(diào)輕松解決開(kāi)發(fā)過(guò)程中所遇到的各種苦逼難題，光讀著便已忍俊不禁。1.TableView不顯示沒(méi)內(nèi)容的Cell怎么辦？類(lèi)似于圖1，我不想讓下面的那些空顯示。很簡(jiǎn)單，添加“=[[UIViewalloc]init];〞試過(guò)都說(shuō)好，加完這句之后就變成了圖2的樣子。2.自定義了leftBarbuttonItem左滑返回手勢(shì)失效了怎么辦？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劃到頂怎么辦？self.automaticallyAdjustsScrollViewInsets

=

NO;

4.鍵盤(pán)事件寫(xiě)得好煩躁，都想摔鍵盤(pán)了怎么辦？買(mǎi)個(gè)結(jié)實(shí)的鍵盤(pán)；使用IQKeyboardManager〔GitHub上可搜索〕，用完之后腰也不疼了，腿也不酸了。5.為什么我的App老是不流暢，到底哪里出了問(wèn)題？如圖：這個(gè)神器叫做：KMCGeigerCounter，快去GitHub上搬運(yùn)吧。6.怎么在不新建一個(gè)Cell的情況下調(diào)整separaLine的位置？_myTableView.separatorInset

=

UIEdgeInsetsMake(0,

100,

0,

0);

7.怎么點(diǎn)擊self.view就讓鍵盤(pán)收起，需要添加一個(gè)tapGestures么？-

(void)touchesBegan:(NSSet

*)touches

withEvent:(UIEvent

*)event

{

[self.viewendEditing:YES];

}

8.怎么給每個(gè)ViewController設(shè)定默認(rèn)的背景圖片？使用基類(lèi)啊，少年。9.想在代碼里改在xib里添加的layoutAttributes，但該怎么用代碼找？像拉Button一樣地拉你的約束，nslayoutattribute也是可以拉線的。10.怎么像Safari一樣滑動(dòng)的時(shí)候隱藏navigationbar？navigationController.hidesBarsOnSwipe

=

Yes

11.導(dǎo)航條返回鍵帶的title太討厭了，怎么讓它消失？[[UIBarButtonItem

appearance]

setBackButtonTitlePositionAdjustment:UIOffsetMake(0,

-60)

forBarMetrics:UIBarMetricsDefault];

12.CoreData用起來(lái)好煩，語(yǔ)法又臭又長(zhǎng)怎么辦？MagicRecord13.CollectionView怎么實(shí)現(xiàn)tableview那種懸停的header？CSStickyHeaderFlowLayout14.能不能只用一個(gè)pan手勢(shì)來(lái)代替UISwipegesture的各個(gè)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.拉伸圖片的時(shí)候怎么才能讓圖片不變形？方法一：UIImage

*image

=

[[UIImage

imageNamed:@"xxx"]

stretchableImageWithLeftCapWidth:10

topCapHeight:10];

注：有開(kāi)發(fā)者提醒這個(gè)已經(jīng)棄用，現(xiàn)在的方法叫resizableImageWithCapInsets。方法二，如圖：16.怎么播放GIF的時(shí)候這么卡，有沒(méi)有好點(diǎn)的庫(kù)？FlipBoard出品的FLAnimatedImage太適合你了。17.怎么一句話添加上拉刷新？使用SVPullToRefresh庫(kù)：[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的小對(duì)勾顏色改成別的顏色？_mTableView.tintColor

=

[UIColorredColor];

19.本來(lái)我的statusbar是lightcontent的，結(jié)果用UIImagePickerController會(huì)導(dǎo)致我的statusbar的樣式變成黑色，怎么辦？-

(void)navigationController:(UINavigationController

*)navigationController

willShowViewController:(UIViewController

*)viewController

animated:(BOOL)animated

{

[[UIApplication

sharedApplication]

setStatusBarStyle:UIStatusBarStyleLightContent];

}

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

forBarMetrics:UIBarMetricsDefault];

=

[UIImagenew];

=

YES;

21.怎么改變uitextfieldplaceholder的顏色和位置？繼承uitextfield，重寫(xiě)這個(gè)方法：-

(void)

drawPlaceholderInRect:(CG