我们在有多个 UIView 层叠时,比如一个按钮被一个 UIView 遮盖时,想要在点击最上层的 UIView 时能触发按钮的相应事件,我们该如何实现呢,初步可以想到几种办法:
1. 把按钮上层的所有 UIView 的 userInteractionEnabled 属性设置为 NO,要是 UIView 有自己的交互事件该如何办呢?而且这个 userInteractionEnabled 不能动态设置,等到点击后决定设置它的 NO 是没用的
2. UIView 接受到点击事件后主动去触发下面按钮的点击,这时的关题有三,按钮没有点击过程中的交换效果、多层 UIView 时不切实际,逐层下传吗、还有就是其他双击、三击或别的手势如何处理
我也一直被前面两种方式纠缠着,同时也让 UIPopoverController 的 NSArray *passthroughViews 属性提醒着,因为对于 UIPopoverController,设置到它的 passthoughViews 属性中的控件事件可以完全从 UIDimmingView 下透出来。但苦于不可能看到 UIPopoverController 的源码,还是后面一而再的 Google 终于发现了 UIView 的方法:
1 | - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event; // recursively calls -pointInside:withEvent:. point is in the receiver's coordinate system |
只要实现了最顶层的 UIView 的 hitTest 方法,在某些情况返回下层的某个按钮实例,即相当于把那个按钮的事件透出来了,比如在点击落在该按钮上时,不管这个按钮在 UIView 下多少层都可以把它挖出来。
关键要理解 hitTest 方法的作用,可参考:
1.http://blog.sina.com.cn/s/blog_677089db01012wpg.html
2. https://github.com/werner77/WEPopover
有两部分代码,分别是 ViewController 和 CustomController
01 | // |
02 | // ViewController.h |
03 | |
04 | // |
05 | // Created by Unmi on 11/15/11. |
06 | // Copyright (c) 2011 http://unmi.cc. All rights reserved. |
07 | // |
08 | |
09 | #import <UIKit/UIKit.h> |
10 | |
11 | @interface ViewController : UIViewController{ |
12 | } |
13 | <a href= "http://my.oschina.net/u/567204" target= "_blank" rel= "nofollow" >@end</a> |
14 |
15 | // |
16 | // ViewController.m |
17 | // |
18 | // Created by Unmi on 11/15/11. |
19 | // Copyright (c) 2011 http://unmi.cc. All rights reserved. |
20 | // |
21 | |
22 | #import "ViewController.h" |
23 | #import "CustomView.h" |
24 | |
25 | @implementation ViewController{ |
26 | UIButton *passthroughButton; |
27 | } |
28 | |
29 | #pragma mark - View lifecycle |
30 | |
31 | - ( void )viewDidLoad |
32 | { |
33 | [super viewDidLoad]; |
34 | |
35 | passthroughButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; |
36 | [passthroughButton setTitle:@ "Passthrough" forState:UIControlStateNormal]; |
37 | [self.view addSubview:passthroughButton]; |
38 | passthroughButton.frame = CGRectMake(20, 50, 120, 28); |
39 | [passthroughButton release]; |
40 | |
41 | CustomView *customView = [[CustomView alloc] initWithFrame:CGRectMake(80, 10, 300, 200)]; |
42 | customView.backgroundColor = [UIColor colorWithRed:1 green:0 blue:0 alpha:.5]; |
43 | customView.passthroughViews = [NSArray arrayWithObject:passthroughButton]; |
44 | [self.view addSubview:customView]; |
45 | [customView release]; |
46 | } |
47 | |
48 | - ( void )dealloc { |
49 | [super dealloc]; |
50 | }<a href= "http://my.oschina.net/u/567204" target= "_blank" rel= "nofollow" >@end</a> |
01 | // |
02 | // CustomView.h |
03 | // TestPopover |
04 | // |
05 | // Created by Unmi on 2/19/12. |
06 | // Copyright (c) 2012 http://unmi.cc. All rights reserved. |
07 | // |
08 | |
09 | #import <UIKit/UIKit.h> |
10 | |
11 | @interface CustomView : UIView |
12 | @property (nonatomic, copy) NSArray *passthroughViews;<a href= "http://my.oschina.net/u/567204" target= "_blank" rel= "nofollow" >@end</a> |
13 | // |
14 | // CustomView.m |
15 | // |
16 | // Created by Unmi on 2/19/12. |
17 | // Copyright (c) 2012 http://unmi.cc. All rights reserved. |
18 | // |
19 | |
20 | #import "CustomView.h" |
21 | |
22 | @interface CustomView() |
23 | -( BOOL ) isPassthroughView: (UIView*) view;<a href= "http://my.oschina.net/u/567204" target= "_blank" rel= "nofollow" >@end</a> |
24 | |
25 | @implementation CustomView{ |
26 | BOOL testHits; |
27 | } |
28 | |
29 | @synthesize passthroughViews=_passthroughViews; |
30 | |
31 | -(UIView*) hitTest:(CGPoint)point withEvent:(UIEvent *)event{ |
32 | if (testHits){ |
33 | return nil; |
34 | } |
35 | |
36 | if (!self.passthroughViews |
37 | || (self.passthroughViews && self.passthroughViews.count == 0)){ |
38 | return self; |
39 | } else { |
40 | |
41 | UIView *hitView = [super hitTest:point withEvent:event]; |
42 | |
43 | if (hitView == self) { |
44 | //Test whether any of the passthrough views would handle this touch |
45 | testHits = YES; |
46 | CGPoint superPoint = [self.superview convertPoint:point fromView:self]; |
47 | UIView *superHitView = [self.superview hitTest:superPoint withEvent:event]; |
48 | testHits = NO; |
49 | |
50 | if ([self isPassthroughView:superHitView]) { |
51 | hitView = superHitView; |
52 | } |
53 | } |
54 | |
55 | return hitView; |
56 | } |
57 | } |
58 | |
59 | - ( BOOL )isPassthroughView:(UIView *)view { |
60 | |
61 | if (view == nil) { |
62 | return NO; |
63 | } |
64 | |
65 | if ([self.passthroughViews containsObject:view]) { |
66 | return YES; |
67 | } |
68 | |
69 | return [self isPassthroughView:view.superview]; |
70 | } |
71 | |
72 | -( void ) dealloc{ |
73 | self.passthroughViews = nil; |
74 | } |