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“self.tableView.tableFooterView = [[UIView alloc] 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?
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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划到顶怎么办?
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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?
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_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?
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- ( void )touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{ [self.view endEditing: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?
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navigationController.hidesBarsOnSwipe = Yes |
11. 导航条返回键带的title太讨厌了,怎么让它消失?
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[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60) forBarMetrics:UIBarMetricsDefault];
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12. CoreData用起来好烦,语法又臭又长怎么办?
MagicRecord
13. CollectionView怎么实现tableview那种悬停的header?
CSStickyHeaderFlowLayout
14. 能不能只用一个pan手势来代替UISwipegesture的各个方向?
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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 ;
} } |
15. 拉伸图片的时候怎么才能让图片不变形?
方法一:
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UIImage *image = [[UIImage imageNamed:@ "xxx" ] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
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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:
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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. 怎么把tableview里Cell的小对勾颜色改成别的颜色?
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_mTableView.tintColor = [UIColor redColor]; |
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?
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- ( 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?
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[self.navigationBar setBackgroundImage:[UIImage new ]
forBarMetrics:UIBarMetricsDefault];
self.navigationBar.shadowImage = [UIImage new ];
self.navigationBar.translucent = YES; |
21. 怎么改变uitextfield placeholder的颜色和位置?
继承uitextfield,重写这个方法:
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- ( void ) drawPlaceholderInRect:(CGRect)rect {
[[UIColor blueColor] setFill];
[self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
} |
22. 你为什么知道这么多奇怪的花招?
去Stack Overflow刷问题啊,少年!