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,光讀著便已忍俊不禁。 1. TableView不顯示沒內容的Cell怎麼辦? 類似於圖1,我不想讓下麵的那些空顯示。很簡單,添加“self.tableView.tableFooterVie ...
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,光讀著便已忍俊不禁。
1. TableView不顯示沒內容的Cell怎麼辦?
類似於圖1,我不想讓下麵的那些空顯示。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;
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3. ScrollView莫名其妙不能在viewController划到頂怎麼辦?
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self.automaticallyAdjustsScrollViewInsets = NO;
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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. 為什麼我的App老是不流暢,到底哪裡出了問題?
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);
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7. 怎麼點擊self.view就讓鍵盤收起,需要添加一個tapGestures麽?
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- ( void )touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[self.view endEditing:YES];
}
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8. 怎麼給每個ViewController設定預設的背景圖片?
使用基類啊,少年。
9. 想在代碼里改在xib里添加的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
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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 appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
forBarMetrics:UIBarMetricsDefault];
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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;
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 > 0) {
direction = UIPanGestureRecognizerDirectionDown;
} else {
direction = UIPanGestureRecognizerDirectionUp;
}
}
else {
if (velocity.x > 0) {
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 ;
}
}
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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];
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註: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];
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18. 怎麼把tableview里Cell的小對勾顏色改成別的顏色?
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_mTableView.tintColor = [UIColor redColor];
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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];
}
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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;
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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];
}
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22. 你為什麼知道這麼多奇怪的花招?
去Stack Overflow刷問題啊,少年!