iOS开发小技巧

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.
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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?
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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?
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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?
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_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?
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• (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?
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self.navigationController.hidesBarsOnSwipe = YES;

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];

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?
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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;
  }
  }

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];

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
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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];

怎么把tableview里cell的小对勾的颜色改成别的颜色？
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_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？
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• (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？
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[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
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• (void) drawPlaceholderInRect:(CGRect)rect {
  [[UIColor blueColor] setFill];
  [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
  }