iOS开发的一些奇巧淫技 .

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 plain copy print ?

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

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 plain copy print ?

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;  

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

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

[objc] view plain copy print ?

1. self.automaticallyAdjustsScrollViewInsets = NO;  

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 plain copy print ?

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

_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 plain copy print ?

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

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

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 plain copy print ?

1. self.navigationController.hidesBarsOnSwipe = YES;  

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 plain copy print ?

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

[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
                                                     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 plain copy print ?

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. }  

- (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;
}
}

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 plain copy print ?

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];  

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

怎么把tableview里cell的小对勾的颜色改成别的颜色？

[objc] view plain copy print ?

1. _mTableView.tintColor = [UIColor redColor];  

_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 plain copy print ?

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

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

怎么把我的navigationbar弄成透明的而不是带模糊的效果？

[objc] view plain copy print ?

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

[self.navigationBar setBackgroundImage:[UIImage new]
                         forBarMetrics:UIBarMetricsDefault];
self.navigationBar.shadowImage = [UIImage new];
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 plain copy print ?

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

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