touchesMoved 没有在 iOS5 中为 iPhone 触发 UIScrollView答案

【问题标题】：touchesMoved not firing in iOS5 for the iPhone for UIScrollViewtouchesMoved 没有在 iOS5 中为 iPhone 触发 UIScrollView
【发布时间】：2011-10-17 13:51:50
【问题描述】：

我有一个带有 ScrollView 的 iPhone 应用程序，它需要响应触摸事件。

为了在滚动视图中支持触摸事件，我需要将它基于一个自定义类，该类捕获触摸事件并将它们传递给主视图。

在 4.3 iPhone 模拟器中运行时按预期工作。使用 NSLOG 条目，我得到如下输出：

2011-10-17 09:28:06.782 SingleView[7000:b303] gameTable began
2011-10-17 09:28:06.784 SingleView[7000:b303] outside began
2011-10-17 09:28:09.976 SingleView[7000:b303] gameTable moved
2011-10-17 09:28:09.976 SingleView[7000:b303] outside moved
2011-10-17 09:28:09.977 SingleView[7000:b303] gameTable moved
2011-10-17 09:28:09.978 SingleView[7000:b303] outside moved
2011-10-17 09:28:10.019 SingleView[7000:b303] gameTable moved
2011-10-17 09:28:10.020 SingleView[7000:b303] outside moved
2011-10-17 09:28:10.046 SingleView[7000:b303] gameTable moved
2011-10-17 09:28:10.047 SingleView[7000:b303] outside moved
2011-10-17 09:28:10.077 SingleView[7000:b303] gameTable moved
2011-10-17 09:28:10.077 SingleView[7000:b303] outside moved
2011-10-17 09:28:10.143 SingleView[7000:b303] gameTable moved
2011-10-17 09:28:10.144 SingleView[7000:b303] outside moved
2011-10-17 09:28:12.433 SingleView[7000:b303] gameTable ended
2011-10-17 09:28:12.434 SingleView[7000:b303] outside ended

gameTable 是自定义类中的事件，它只是将它传递给外部视图。

如果您在 iOS 5 iPhone 模拟器中运行相同的应用程序，您会得到如下输出：

2011-10-17 09:41:46.319 SingleView[7077:f803] gameTable began
2011-10-17 09:41:46.322 SingleView[7077:f803] outside began
2011-10-17 09:41:47.851 SingleView[7077:f803] gameTable moved
2011-10-17 09:41:47.852 SingleView[7077:f803] outside moved
2011-10-17 09:41:47.853 SingleView[7077:f803] gameTable moved
2011-10-17 09:41:47.860 SingleView[7077:f803] gameTable moved
2011-10-17 09:41:47.893 SingleView[7077:f803] gameTable moved
2011-10-17 09:41:47.916 SingleView[7077:f803] gameTable moved
2011-10-17 09:41:47.945 SingleView[7077:f803] gameTable moved
2011-10-17 09:41:48.009 SingleView[7077:f803] gameTable moved
2011-10-17 09:41:48.062 SingleView[7077:f803] gameTable moved

注意外部移动事件只触发一次。

这里是代码。这是 Xcode 中的单视图项目。

//
//  XYZAppDelegate.h
//  SingleView
//

#import <UIKit/UIKit.h>

@class XYZViewController;

@interface XYZAppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) XYZViewController *viewController;

@end



//
//  XYZAppDelegate.m
//  SingleView
//

#import "XYZAppDelegate.h"

#import "XYZViewController.h"

@implementation XYZAppDelegate

@synthesize window = _window;
@synthesize viewController = _viewController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.viewController = [[XYZViewController alloc] initWithNibName:@"XYZViewController" bundle:nil];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}

@end


//
//  XYZViewController.h
//  SingleView
//

#import <UIKit/UIKit.h>
#import "GameTableScrollView.h"

@interface XYZViewController : UIViewController <UIScrollViewDelegate> {
    IBOutlet GameTableScrollView *outsideScrollView;

}

@property (nonatomic, retain) GameTableScrollView *outsideScrollView;

@end

    //
    //  XYZViewController.m
    //  SingleView
    //

    #import "XYZViewController.h"

    @implementation XYZViewController
    @synthesize outsideScrollView;

    #pragma mark - View lifecycle

    - (void)viewDidLoad
    {
        [super viewDidLoad];
        // Do any additional setup after loading the view, typically from a nib.

        [outsideScrollView setScrollEnabled:NO];
        [outsideScrollView setContentSize:CGSizeMake(480,555)];
    }


    // Handles the start of a touch
    -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
    {
        NSLog(@"outside began");
    }

    // Handles the continuation of a touch.
    -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
    {  
        NSLog(@"outside moved");
    }


    // Handles the end of a touch event.
    -(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
    {
        NSLog(@"outside ended");
    }

    -(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
    {
        NSLog(@"outside cancelled");
    }

    @end

    //
    //  GameTableScrollView.h
    //

    #import <UIKit/UIKit.h>

    @interface GameTableScrollView : UIScrollView <UIScrollViewDelegate> {

    }

    @end

//
//  GameTableScrollView.m
//

#import "GameTableScrollView.h"

@implementation GameTableScrollView

#pragma mark - Touch 

// Handles the start of a touch
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"gameTable began");
    if (!self.dragging) {
        [self.nextResponder touchesBegan:touches withEvent:event];
    }
    else [super touchesBegan:touches withEvent:event];
}


// Handles the continuation of a touch.
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{  
    NSLog(@"gameTable moved");
    if (!self.dragging) {
        [self.nextResponder touchesMoved:touches withEvent:event];
    }
    else [super touchesMoved:touches withEvent:event];
}


// Handles the end of a touch event.
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"gameTable ended");
    if (!self.dragging) {
        [self.nextResponder touchesEnded:touches withEvent:event];
    } 
    else [super touchesEnded:touches withEvent:event];
}

-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"gameTable cancelled");
    if (!self.dragging) {
        [self.nextResponder touchesCancelled:touches withEvent:event];
    } 
    else [super touchesCancelled:touches withEvent:event];
}

@end

【问题讨论】：

上面的代码足以重现问题。通常在 UIScrollView 中有一个 UIImageView ，用户将拖动它。这就是我需要处理触摸事件的原因。
我不确定这是否是答案，但您可能想在 XYZViewController.h 文件中使用 GameTableScrollView 而不是使用 UIScrollView。此外，您可能需要导入 GameTableScrollView 标头，进入 IB 并更改滚动视图的类，然后将其重新连接回 IBOutlet。
值得一试，但很抱歉没有运气。我已经用您建议的更改更新了原始帖子中的代码，以便您查看。
我已经记录了 Apple 的一个错误，因为我觉得这不是正确的行为。当（如果）我得到回复时，我会在这里发布答案。
与此同时，我找到了另一种方法来完成它。我扩展了 UIScrollViewDelegate 以包含我自己版本的 touchevents 的方法。然后我在我的子类 UIScrollView 中调用这些方法。

标签： iphone uiscrollview ios5 touchesmoved

【解决方案1】：

我最近向类似的question 发布了answer。

在GameTableScrollView 你有这个代码：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"gameTable began");
    if (!self.dragging) {
        [self.nextResponder touchesBegan:touches withEvent:event];
    }
    else [super touchesBegan:touches withEvent:event];
}

要解决问题，您需要更改此行：

[self.nextResponder touchesBegan:touches withEvent:event];

对此：

[[self.nextResponder nextResponder] touchesBegan:touches withEvent:event];

这将导致GameTableScrollView 将触摸事件传递给外部视图。

【讨论】：