本文作者@葉孤城___,他結合自身的實踐開發經驗總結出了22個iOS開發的小技巧,以非常歡樂的語調輕鬆解決開發過程中所遇到的各種苦逼難題,光讀着便已忍俊不禁。
1. TableView不顯示沒內容的Cell怎麼辦?
類似於圖1,我不想讓下面的那些空顯示。很簡單,添加“self.tableView.tableFooterView = [[UIView alloc] init];”試過都說好,加完這句之後就變成了圖2的樣子。
2. 自定義了leftBarbuttonItem左滑返回手勢失效了怎麼辦?
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self.navigationItem.leftBarButtonItem
= [[UIBarButtonItem alloc] initWithImage:img style:UIBarButtonItemStylePlain target:self action:@selector(onBack:)]; self.navigationController.interactivePopGestureRecognizer.delegate
= (id<UIGestureRecognizerDelegate>)self; |
3. ScrollView莫名其妙不能在viewController劃到頂怎麼辦?
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self.automaticallyAdjustsScrollViewInsets
= NO; |
4. 鍵盤事件寫得好煩躁,都想摔鍵盤了怎麼辦?
- 買個結實的鍵盤;
- 使用IQKeyboardManager(GitHub上可搜索),用完之後腰也不疼了,腿也不酸了。
5. 爲什麼我的App老是不流暢,到底哪裏出了問題?
如圖:
這個神器叫做:KMCGeigerCounter ,快去GitHub上搬運吧。
6. 怎麼在不新建一個Cell的情況下調整separaLine的位置?
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_myTableView.separatorInset
= UIEdgeInsetsMake(0, 100, 0, 0); |
7. 怎麼點擊self.view就讓鍵盤收起,需要添加一個tapGestures麼?
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( void )touchesBegan:(NSSet
*)touches withEvent:(UIEvent *)event { [self.view
endEditing:YES]; } |
8. 怎麼給每個ViewController設定默認的背景圖片?
使用基類啊,少年。
9. 想在代碼裏改在xib裏添加的layoutAttributes,但該怎麼用代碼找?
像拉Button一樣地拉你的約束,nslayoutattribute也是可以拉線的。
10. 怎麼像Safari一樣滑動的時候隱藏navigationbar?
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navigationController.hidesBarsOnSwipe
= Yes |
11. 導航條返回鍵帶的title太討厭了,怎麼讓它消失?
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[[UIBarButtonItem
<span id= "3_nwp" style= "width:
auto; height: auto; float: none;" ><a
id= "3_nwl" href= "http://cpro.baidu.com/cpro/ui/uijs.php?c=news&cf=1001&ch=0&di=128&fv=11&jk=daa32d9bb1e0b2b5&k=app&k0=app&kdi0=0&luki=3&n=10&p=baidu&q=06011078_cpr&rb=0&rs=1&seller_id=1&sid=b5b2e0b19b2da3da&ssp2=1&stid=0&t=tpclicked3_hc&tu=u1922429&u=http%3A%2F%2Fwww%2Eadmin10000%2Ecom%2Fdocument%2F5765%2Ehtml&urlid=0" target= "_blank" mpid= "3" style= "text-decoration:
none;" ><span
style= "color:#0000ff;font-size:14px;width:auto;height:auto;float:none;" >app</span></a></span>earance]
setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60) forBarMetrics:UIBarMetricsDefault]; |
12. CoreData用起來好煩,語法又臭又長怎麼辦?
MagicRecord
13. CollectionView怎麼實現tableview那種懸停的header?
CSStickyHeaderFlowLayout
14. 能不能只用一個pan手勢來代替UISwipegesture的各個方向?
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( void )pan:(UIPanGestureRecognizer
*)sender { typedef NS_ENUM(NSUInteger,
UIPanGestureRecognizerDirection) { UIPanGestureRecognizerDirectionUndefined, UIPanGestureRecognizerDirectionUp, UIPanGestureRecognizerDirectionDown, UIPanGestureRecognizerDirectionLeft, UIPanGestureRecognizerDirectionRight }; static UIPanGestureRecognizerDirection
direction = UIPanGestureRecognizerDirectionUndefined; <span
id= "1_nwp" style= "width:
auto; height: auto; float: none;" ><a
id= "1_nwl" href= "http://cpro.baidu.com/cpro/ui/uijs.php?c=news&cf=1001&ch=0&di=128&fv=11&jk=daa32d9bb1e0b2b5&k=switch&k0=switch&kdi0=0&luki=4&n=10&p=baidu&q=06011078_cpr&rb=0&rs=1&seller_id=1&sid=b5b2e0b19b2da3da&ssp2=1&stid=0&t=tpclicked3_hc&tu=u1922429&u=http%3A%2F%2Fwww%2Eadmin10000%2Ecom%2Fdocument%2F5765%2Ehtml&urlid=0" target= "_blank" mpid= "1" style= "text-decoration:
none;" ><span
style= "color:#0000ff;font-size:14px;width:auto;height:auto;float:none;" > switch </span></a></span>
(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
> 0) { direction
= UIPanGestureRecognizerDirectionDown; }
else { direction
= UIPanGestureRecognizerDirectionUp; } } else { if (velocity.x
> 0) { direction
= UIPanGestureRecognizerDirectionRight; }
else { direction
= UIPanGestureRecognizerDirectionLeft; } } } break ; } case UIGestureRecognizerStateChanged:
{ <span
id= "2_nwp" style= "width:
auto; height: auto; float: none;" ><a
id= "2_nwl" href= "http://cpro.baidu.com/cpro/ui/uijs.php?c=news&cf=1001&ch=0&di=128&fv=11&jk=daa32d9bb1e0b2b5&k=switch&k0=switch&kdi0=0&luki=4&n=10&p=baidu&q=06011078_cpr&rb=0&rs=1&seller_id=1&sid=b5b2e0b19b2da3da&ssp2=1&stid=0&t=tpclicked3_hc&tu=u1922429&u=http%3A%2F%2Fwww%2Eadmin10000%2Ecom%2Fdocument%2F5765%2Ehtml&urlid=0" target= "_blank" mpid= "2" style= "text-decoration:
none;" ><span
style= "color:#0000ff;font-size:14px;width:auto;height:auto;float:none;" > switch </span></a></span>
(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 ; } } |
15. 拉伸圖片的時候怎麼才能讓圖片不變形?
方法一:
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UIImage
*image = [[UIImage imageNamed:@ "xxx" ]
stretchableImageWithLeftCapWidth:10 topCapHeight:10]; |
注:有開發者提醒這個已經棄用,現在的方法叫resizableImageWithCapInsets。
方法二,如圖:
16. 怎麼播放GIF的時候這麼卡,有沒有好點的庫?
FlipBoard出品的FLAnimatedImage太適合你了。
17. 怎麼一句話添加上拉刷新?
使用SVPullToRefresh庫:
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[tableView
addPullToRefreshWithActionHandler:^{ //
prepend data to dataSource, insert cells at top of table view //
call [tableView.pullToRefreshView stopAnimating] when done }
position:SVPullToRefreshPositionBottom]; |
18. 怎麼把tableview裏Cell的小對勾顏色改成別的顏色?
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_mTableView.tintColor
= [UIColor redColor]; |
19. 本來我的statusbar是lightcontent的,結果用UIImagePickerController會導致我的statusbar的樣式變成黑色,怎麼辦?
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( void )navigationController:(UINavigationController
*)navigationController willShowViewController:(UIViewController *)viewController animated:( BOOL )animated { [[UIApplication
sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent]; } |
20. 怎麼把我的navigationbar弄成透明的而不是帶模糊的效果?
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[self.navigationBar
setBackgroundImage:[UIImage new ] forBarMetrics:UIBarMetricsDefault]; self.navigationBar.shadowImage
= [UIImage new ]; self.navigationBar.translucent
= YES; |
21. 怎麼改變uitextfield placeholder的顏色和位置?
繼承uitextfield,重寫這個方法:
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( void )
drawPlaceholderInRect:(CGRect)rect { [[UIColor
blueColor] setFill]; [self.placeholder
drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment]; } |
22. 你爲什麼知道這麼多奇怪的花招?
去Stack Overflow刷問題啊,少年!