iOS开发的一些奇巧淫技2

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 > ) {
                     direction = UIPanGestureRecognizerDirectionDown;
                 } else {
                     direction = UIPanGestureRecognizerDirectionUp;
                 }
             }

             else {
                 if (velocity.x > ) {
                     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？

 UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth: topCapHeight:];
 (刚才有人提醒这个已经deprecated了哈,现在的方法叫resizableImageWithCapInsets). 

1. 

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

 [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？

_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？

 - (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？

 [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

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

你为什么知道这么多奇怪的花招？

去stackoverflow刷问题啊，少年！