iOS開發的一些奇巧淫技2

能不能只用一個pan手勢來代替UISwipegesture的各個方向?

- (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; 
} 
 
} 

拉伸圖片的時候怎么才能讓圖片不變形？

1. UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
   (剛才有人提醒這個已經deprecated了哈,現在的方法叫resizableImageWithCapInsets).

2. 

怎么播放GIF的時候這么卡，有沒有好點的庫？

FlipBoard出品的太適合你了。https://github.com/Flipboard/FLAnimatedImage

怎么一句話添加上拉刷新？

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的小對勾的顏色改成別的顏色？

_mTableView.tintColor = [UIColor redColor]; 

本來我的statusbar是lightcontent的，結果用UIImagePickerController會導致我的statusbar的樣式變成黑色，怎么辦？

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

怎么把我的navigationbar弄成透明的而不是帶模糊的效果？

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

怎么改變uitextfield placeholder的顏色和位置？

繼承uitextfield，重寫這個方法

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

你為什么知道這么多奇怪的花招？

去stackoverflow刷問題啊，少年！