UIEvent - 3

来源：互联网发布：如何注册淘宝旺旺编辑：程序博客网时间：2024/05/17 09:18

对上一节的例子做一些修改：

LBEventTestView.h

#import <UIKit/UIKit.h>@interface LBEventTestView : UIView@property (nonatomic, strong) NSString* colorString;//增加辨识变量colorString@end

LBEventTestView.m

#import "LBEventTestView.h"@implementation LBEventTestView- (UIView*)hitTest:(CGPoint)point withEvent:(UIEvent *)event{        NSLog(@"ColorString hitTest : %@,  %@", self.colorString, [super hitTest:point withEvent:event]);        return [super hitTest:point withEvent:event];}- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event{    NSLog(@"ColorString pointInside : %@,  %@", self.colorString, [super pointInside:point withEvent:event]? @"YES" : @"NO");        return [super pointInside:point withEvent:event];}@end

调用的视图控制器：

#import "Masonry.h"#import "LBEventTestView.h"#import "UIEventTestController.h"@implementation UIEventTestController- (void)viewDidLoad{    [super viewDidLoad];        //RED    LBEventTestView* redView = [[LBEventTestView alloc] init];    redView.colorString = @"RED";    [redView setBackgroundColor:[UIColor redColor]];    [self.view addSubview:redView];        [redView mas_makeConstraints:^(MASConstraintMaker* make){            make.center.mas_equalTo(self.view);        make.size.mas_equalTo(CGSizeMake(250, 350));    }];            //YELLOW    LBEventTestView* yellow = [LBEventTestView new];    yellow.colorString = @"YELLOW";    [yellow setBackgroundColor:[UIColor yellowColor]];    [redView addSubview:yellow];        [yellow mas_makeConstraints:^(MASConstraintMaker* make){                make.centerX.equalTo(redView);        make.size.mas_equalTo(CGSizeMake(100, 80));        make.top.mas_equalTo(redView.mas_top).with.offset(30);            }];        //GREEN    LBEventTestView* green = [LBEventTestView new];    green.colorString = @"GREEN";    [green setBackgroundColor:[UIColor greenColor]];    [redView addSubview:green];        [green mas_makeConstraints:^(MASConstraintMaker* make){            make.centerX.equalTo(redView);        make.size.mas_equalTo(yellow);        make.bottom.mas_equalTo(redView.mas_bottom).with.offset(-30);        }];}@end

如图：

分别点击这4个区域然后参考上文的文章理解。

挑选一个点击区域1和区域4来讲解：

区域1:

解析：点击白色区域1，开始遍历子视图的时候发现点击点不在RED红色区域（因为return的都是NO），就不继续调用别的在RED相关的子视图了。那一定会问为什么会调用了两次？如图上所示是两次，看看文档的方法描述：

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event;   // recursively calls -pointInside:withEvent:. point is in the receiver's coordinate system

就是这个方法搞的鬼，它是用递归式的调用。所以调用的是多次，具体是多少次，我还真不敢说。（因为不懂哈哈）

区域4:

可以清楚看到，yellow视图同为RED的子视图，是完全不会去调用的。连Return NO的机会都没有。慢慢的似乎有一点点的规律，上一节的两层视图的结构就会调用2次，这一节的3层视图的结构就会调用6次，我严重怀疑recursively是不是视图继承层数 H * 2 呢。以后懂了再在这里阐述吧！

0 0