iOS开发的一些奇巧淫技

http://blog.csdn.net/Dwarven/article/details/42388711

TableView不显示没内容的Cell怎么办?

类似这种,我不想让下面那些空的显示.

很简单.

[objc] view plaincopy

1. self.tableView.tableFooterView = [[UIView alloc] init];

试过的都说好.

加完这句之后就变成了这样.

自定义了leftBarbuttonItem左滑返回手势失效了怎么办?

[objc] view plaincopy

1. self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
2. initWithImage:img
3. style:UIBarButtonItemStylePlain
4. target:self
5. action:@selector(onBack:)];
6. self.navigationController.interactivePopGestureRecognizer.delegate = (id)self;

ScrollView莫名其妙不能在viewController划到顶怎么办?

[objc] view plaincopy

1. self.automaticallyAdjustsScrollViewInsets = NO;

键盘事件写的好烦躁,都想摔键盘了,怎么办?

1.买个结实的键盘.

2.使用IQKeyboardManager(github上可搜索),用完之后腰也不疼了,腿也不酸了.

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搬运吧.

怎么在不新建一个Cell的情况下调整separaLine的位置?

[objc] view plaincopy

1. _myTableView.separatorInset = UIEdgeInsetsMake(0, 100, 0, 0);

怎么点击self.view就让键盘收起,需要添加一个tapGestures么?

[objc] view plaincopy

1. - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
2. {
3. [self.view endEditing:YES];
4. }

怎么给每个ViewController设定默认的背景图片?

使用基类啊,少年。

想在代码里改在xib里添加的layoutAttributes,但是怎么用代码找啊?

像拉button一样的拉你的约束.nslayoutattribute也是可以拉线的.

怎么像safari一样滑动的时候隐藏navigationbar?

[objc] view plaincopy

1. self.navigationController.hidesBarsOnSwipe = YES;

导航条返回键带的title太讨厌了,怎么让它消失!

[objc] view plaincopy

1. [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
2. forBarMetrics:UIBarMetricsDefault];

CoreData用起来好烦,语法又臭又长,怎么办?

Magical Record https://github.com/magicalpanda/MagicalRecord

CollectionView 怎么实现tableview那种悬停的header?

CSStickyHeaderFlowLayout

能不能只用一个pan手势来代替UISwipegesture的各个方向?

[objc] view plaincopy

1. - (void)pan:(UIPanGestureRecognizer *)sender
2. {
3. typedef NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) {
4. UIPanGestureRecognizerDirectionUndefined,
5. UIPanGestureRecognizerDirectionUp,
6. UIPanGestureRecognizerDirectionDown,
7. UIPanGestureRecognizerDirectionLeft,
8. UIPanGestureRecognizerDirectionRight
9. };
10. static UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined;
11. switch (sender.state) {
12. case UIGestureRecognizerStateBegan: {
13. if (direction == UIPanGestureRecognizerDirectionUndefined) {
14. CGPoint velocity = [sender velocityInView:recognizer.view];
15. BOOL isVerticalGesture = fabs(velocity.y) > fabs(velocity.x);
16. if (isVerticalGesture) {
17. if (velocity.y > 0) {
18. direction = UIPanGestureRecognizerDirectionDown;
19. } else {
20. direction = UIPanGestureRecognizerDirectionUp;
21. }
22. }
23. else {
24. if (velocity.x > 0) {
25. direction = UIPanGestureRecognizerDirectionRight;
26. } else {
27. direction = UIPanGestureRecognizerDirectionLeft;
28. }
29. }
30. }
31. break;
32. }
33. case UIGestureRecognizerStateChanged: {
34. switch (direction) {
35. case UIPanGestureRecognizerDirectionUp: {
36. [self handleUpwardsGesture:sender];
37. break;
38. }
39. case UIPanGestureRecognizerDirectionDown: {
40. [self handleDownwardsGesture:sender];
41. break;
42. }
43. case UIPanGestureRecognizerDirectionLeft: {
44. [self handleLeftGesture:sender];
45. break;
46. }
47. case UIPanGestureRecognizerDirectionRight: {
48. [self handleRightGesture:sender];
49. break;
50. }
51. default: {
52. break;
53. }
54. }
55. break;
56. }
57. case UIGestureRecognizerStateEnded: {
58. direction = UIPanGestureRecognizerDirectionUndefined;
59. break;
60. }
61. default:
62. break;
63. }
64. }

拉伸图片的时候怎么才能让图片不变形？

1.UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];

2.

怎么播放GIF的时候这么卡，有没有好点的库？

FlipBoard出品的太适合你了：https://github.com/Flipboard/FLAnimatedImage

怎么一句话添加上拉刷新？

https://github.com/samvermette/SVPullToRefresh

[objc] view plaincopy

1. [tableView addPullToRefreshWithActionHandler:^{
2. // prepend data to dataSource, insert cells at top of table view
3. // call [tableView.pullToRefreshView stopAnimating] when done
4. } position:SVPullToRefreshPositionBottom];

怎么把tableview里cell的小对勾的颜色改成别的颜色？

[objc] view plaincopy

1. _mTableView.tintColor = [UIColor redColor];

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？

[objc] view plaincopy

1. - (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
2. {
3. [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
4. }

怎么把我的navigationbar弄成透明的而不是带模糊的效果？

[objc] view plaincopy

1. [self.navigationBar setBackgroundImage:[UIImage new]
2. forBarMetrics:UIBarMetricsDefault];
3. self.navigationBar.shadowImage = [UIImage new];
4. self.navigationBar.translucent = YES;

怎么改变uitextfield placeholder的颜色和位置？

继承uitextfield，重写这个方法

[objc] view plaincopy

1. - (void) drawPlaceholderInRect:(CGRect)rect {
2. [[UIColor blueColor] setFill];
3. [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
4. }