iOS开发的一些奇巧淫技

1.

TableView不显示没内容的Cell怎么办?

定义了4个有内容的cell，可是屏幕内一下出现10个cell，只有4个有内容，剩下6个没内容，怎么去掉？

答：self.tableView.tableFooterView = [[UIView alloc] init];

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?

1 self.automaticallyAdjustsScrollViewInsets = NO; 4. 怎么在不新建一个Cell的情况下调整separaLine的位置? 1 _myTableView.separatorInset = UIEdgeInsetsMake(0, 100, 0, 0); 5. 怎么点击self.view就让键盘收起,需要添加一个tapGestures么? 1 2 3 4 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {     [self.view endEditing:YES]; } 6. 怎么像safari一样滑动的时候隐藏navigationbar? 1 navigationController.hidesBarsOnSwipe = Yes 7.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]; 8.怎么把tableview里cell的小对勾的颜色改成别的颜色？ 1 _mTableView.tintColor = [UIColor redColor]; 9. 能不能只用一个pan手势来代替UISwipegesture的各个方向? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 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 ; } } 10 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 11.怎么一句话添加上拉刷新？ https://github.com/samvermette/SVPullToRefresh 1 2 3 4 [tableView addPullToRefreshWithActionHandler:^{ // prepend data to dataSource, insert cells at top of table view // call [tableView.pullToRefreshView stopAnimating] when done } position:SVPullToRefreshPositionBottom]; 12.怎么把我的navigationbar弄成透明的而不是带模糊的效果？ 1 2 3 4 [self.navigationBar setBackgroundImage:[UIImage  new ]                           forBarMetrics:UIBarMetricsDefault]; self.navigationBar.shadowImage = [UIImage  new ]; self.navigationBar.translucent = YES; 13 怎么改变uitextfield placeholder的颜色和位置？ 继承uitextfield，重写这个方法 1 2 3 4 - (void) drawPlaceholderInRect:(CGRect)rect {      [[UIColor blueColor] setFill];      [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment]; }