1 - (void)pan:(UIPanGestureRecognizer *)sender
 2 {
 3 
 4 typedef NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) {
 5     UIPanGestureRecognizerDirectionUndefined,
 6     UIPanGestureRecognizerDirectionUp,
 7     UIPanGestureRecognizerDirectionDown,
 8     UIPanGestureRecognizerDirectionLeft,
 9     UIPanGestureRecognizerDirectionRight
10 };
11 
12 static UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined;
13 
14 switch (sender.state) {
15 
16     case UIGestureRecognizerStateBegan: {
17 
18         if (direction == UIPanGestureRecognizerDirectionUndefined) {
19 
20             CGPoint velocity = [sender velocityInView:recognizer.view];
21 
22             BOOL isVerticalGesture = fabs(velocity.y) > fabs(velocity.x);
23 
24             if (isVerticalGesture) {
25                 if (velocity.y > 0) {
26                     direction = UIPanGestureRecognizerDirectionDown;
27                 } else {
28                     direction = UIPanGestureRecognizerDirectionUp;
29                 }
30             }
31 
32             else {
33                 if (velocity.x > 0) {
34                     direction = UIPanGestureRecognizerDirectionRight;
35                 } else {
36                     direction = UIPanGestureRecognizerDirectionLeft;
37                 }
38             }
39         }
40 
41         break;
42     }
43 
44     case UIGestureRecognizerStateChanged: {
45         switch (direction) {
46             case UIPanGestureRecognizerDirectionUp: {
47                 [self handleUpwardsGesture:sender];
48                 break;
49             }
50             case UIPanGestureRecognizerDirectionDown: {
51                 [self handleDownwardsGesture:sender];
52                 break;
53             }
54             case UIPanGestureRecognizerDirectionLeft: {
55                 [self handleLeftGesture:sender];
56                 break;
57             }
58             case UIPanGestureRecognizerDirectionRight: {
59                 [self handleRightGesture:sender];
60                 break;
61             }
62             default: {
63                 break;
64             }
65         }
66         break;
67     }
68 
69     case UIGestureRecognizerStateEnded: {
70         direction = UIPanGestureRecognizerDirectionUndefined;   
71         break;
72     }
73 
74     default:
75         break;
76 }
77 
78 }

1 UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
2 (刚才有人提醒这个已经deprecated了哈,现在的方法叫resizableImageWithCapInsets). 

1 [tableView addPullToRefreshWithActionHandler:^{
2 // prepend data to dataSource, insert cells at top of table view
3 // call [tableView.pullToRefreshView stopAnimating] when done
4 } position:SVPullToRefreshPositionBottom];

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

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

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