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iOS小技巧

iOS小技巧

作者: 咋了爸爸 | 来源:发表于2016-11-08 15:33 被阅读20次
    1-->TableView不显示没内容的Cell怎么办?
        很简单
        self.tableView.tableFooterView = [[UIView alloc] init];
        试过的都说好.
    
    
    2-->自定义了leftBarbuttonItem左滑返回手势失效了怎么办?
    
        self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
                                             initWithImage:img
                                             style:UIBarButtonItemStylePlain
                                             target:self
                                             action:@selector(onBack:)];
       self.navigationController.interactivePopGestureRecognizer.delegate = (id)self;
    
    
    
    3-->ScrollView莫名其妙不能在viewController划到顶怎么办?
        self.automaticallyAdjustsScrollViewInsets = NO;
    
    
    4-->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.
    
    
    5-->为什么我的app老是不流畅,到底哪里出了问题?
       这个神器叫做:KMCGeigerCounter,快去github搬运吧.
    
    
    6-->怎么在不新建一个Cell的情况下调整(隐藏)separaLine的位置?
       _myTableView.separatorInset = UIEdgeInsetsMake(0, screenWidth, 0, 0);
    (注意: titleLabel的位置也会跟着改变)
    
    
    7-->怎么点击self.view就让键盘收起,需要添加一个tapGestures么 ? NO
      - (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.
    
    
    10-->怎么像safari一样滑动的时候隐藏navigationbar?
        navigationController.hidesBarsOnSwipe = Yes
    
    
    11-->导航条返回键带的title太讨厌了,怎么让它消失!
         [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
                                                         forBarMetrics:UIBarMetricsDefault];
                                                         
    
    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?
    - (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?
        1.UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
        2.使用九切片技术
    
    
    16-->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: 
    
    
    17-->怎么一句话添加上拉刷新?
         使用MJRefresh 最新的已经支持gif 图和添加刷新图片了
    
    18-->怎么把tableview里cell的小对勾的颜色改成别的颜色?
        _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?
    
    - (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?
    
        [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
    
    - (void) drawPlaceholderInRect:(CGRect)rect {
        [[UIColor blueColor] setFill];
        [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
    }
    
    
    22-->如何修改导航返回按钮的标题(默认是上一级导航的title) ?
        // 推到下个页面之前 修改backItem标题为返回
        UIBarButtonItem *backBtn = [[UIBarButtonItem alloc] init];
        backBtn.title = @"返回";
        self.navigationItem.backBarButtonItem = backBtn;
        [self.navigationController pushViewController:zhtVC animated:YES];
    
    

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