将手势识别器附加到多个图像视图
将当前手势识别器附加到多个图像视图时,我今天遇到了一些奇怪的事情。它只附加到最后一个,换句话说,它只能附加到一个视图!将手势识别器附加到多个图像视图
我不得不创建多个手势识别器来满足我的要求。
以下是我所做的。我做得对吗?这是将识别器附加到多个图像视图的唯一方法吗?
请注意,我不想使用UITableView或UIVIew并将其中的所有图像,并将手势识别器仅附加到UITableView或UIVIew。我有所有图像分散,我必须检测哪个图像被拖动。谢谢。
[imgView1 setUserInteractionEnabled:YES];
[imgView1 setMultipleTouchEnabled:YES];
[imgView2 setUserInteractionEnabled:YES];
[imgView2 setMultipleTouchEnabled:YES];
[imgView3 setUserInteractionEnabled:YES];
[imgView3 setMultipleTouchEnabled:YES];
[imgView4 setUserInteractionEnabled:YES];
[imgView4 setMultipleTouchEnabled:YES];
[imgView5 setUserInteractionEnabled:YES];
[imgView5 setMultipleTouchEnabled:YES];
[imgView6 setUserInteractionEnabled:YES];
[imgView6 setMultipleTouchEnabled:YES];
//Attach gesture recognizer to each imagviews
gestureRecognizer1 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
gestureRecognizer1.delegate = self;
gestureRecognizer2 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
gestureRecognizer2.delegate = self;
gestureRecognizer3 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
gestureRecognizer3.delegate = self;
gestureRecognizer4 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
gestureRecognizer4.delegate = self;
gestureRecognizer5 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
gestureRecognizer5.delegate = self;
gestureRecognizer6 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
gestureRecognizer6.delegate = self;
[imgView1 addGestureRecognizer:gestureRecognizer1];
[imgView2 addGestureRecognizer:gestureRecognizer2];
[imgView3 addGestureRecognizer:gestureRecognizer3];
[imgView4 addGestureRecognizer:gestureRecognizer4];
[imgView5 addGestureRecognizer:gestureRecognizer5];
[imgView6 addGestureRecognizer:gestureRecognizer6];
是的,每个手势识别器有一个视图。所以,如果你只想要一个识别器,把它放在上海华,例如:
UILongPressGestureRecognizer *gestureRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
[self.view addGestureRecognizer:gestureRecognizer];
,然后在您的处理程序,您可以:
- (void)handleLongPress:(UILongPressGestureRecognizer *)sender
{
CGPoint location = [sender locationInView:self.view];
if (sender.state == UIGestureRecognizerStateBegan)
{
for (UIView *view in self.view.subviews)
{
if ([view isKindOfClass:[UIImageView class]] && CGRectContainsPoint(view.frame, location))
{
UIImageView *image = (UIImageView *) view;
// ok, now you know which image you received your long press for
// do whatever you wanted on it at this point
return;
}
}
}
}
顺便说一句,如果你这样做,你不需要担心在图像上启用用户交互。
最后,除非您要符合UIGestureRecognizerDelegate
,否则不需要担心指定您的手势识别器的代表。另外请注意,我为识别器使用了一个本地变量,因为没有理由挂在它上面。
更新:
虽然上面的代码工作正常,或许更重要的是一个自定义的长按手势识别,如果长按并没有发生过的图像(这样它更是会失败如果您在视图中发现其他手势识别器,可能会发挥出色)。所以:
#import <UIKit/UIGestureRecognizerSubclass.h>
@interface ImageLongPressGestureRecognizer : UILongPressGestureRecognizer
@property (nonatomic, weak) UIImageView *imageview;
@end
@implementation ImageLongPressGestureRecognizer
@synthesize imageview = _imageview;
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
self.imageview = nil;
[super touchesBegan:touches withEvent:event];
CGPoint location = [self locationInView:self.view];
for (UIView *view in self.view.subviews)
{
if ([view isKindOfClass:[UIImageView class]] && CGRectContainsPoint(view.frame, location))
{
self.imageview = (UIImageView *)view;
return;
}
}
self.state = UIGestureRecognizerStateFailed;
}
@end
然后相应地创建您的手势识别,使用这个新的子类:
ImageLongPressGestureRecognizer *gestureRecognizer = [[ImageLongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];
[self.view addGestureRecognizer:gestureRecognizer];
然后,作为这个子类的一个不错的效益,你的主要手势识别被简化,即:
- (void)handleLongPress:(ImageLongPressGestureRecognizer *)sender
{
if (sender.state == UIGestureRecognizerStateBegan)
{
// you can now do whatever you want with sender.imageview, e.g. this makes it blink for you:
[UIView animateWithDuration:0.5
animations:^{
sender.imageview.alpha = 0.0;
} completion:^(BOOL finished){
[UIView animateWithDuration:0.5
animations:^{
sender.imageview.alpha = 1.0;
}
completion:nil];
}];
}
}
您无法将手势识别器附加到多个对象(如您发现的那样)。你正在做的一个解决方案可能是UIImageView的子类,并在该类中设置代码,以便每个视图创建其识别器等。
谢谢。创建子类是一个好主意。 – applefreak
我想,首先,你应该制作一个视图数组和识别器数组(可变数组,如果需要的话),然后填充它。它将帮助您使用循环来避免代码重复。
至于多视图与一个识别器 - 不,这是不可能的,answered here。
非常感谢!我需要关心我不想添加手势的图像浏览!我可以使用触摸位置来做到这一点。 – applefreak
Omg,我今天才发现这个,我想知道为什么我的darn UITableViewCell只能用于最后一个被刷过的单元格:P – Zhang