UIControl：sendActionsForControlEvents省略了UIEvent [英] UIControl: sendActionsForControlEvents omits UIEvent

问题描述

我想实现UIControl的自定义子类。除了一个致使我吐牙的致命问题外，它的工作非常精美。每当我使用sendActionsForControlEvents：发送动作消息时，它都会省略包含UIEvent。例如，如果我将其链接到具有以下签名的方法：

I want to implement a custom subclass of UIControl. It works beautifully except for one fatal problem that is making me spit teeth. Whenever I use sendActionsForControlEvents: to send an action message out, it omits to include a UIEvent. For example, if I link it to a method with the following signature:

- (IBAction) controlTouched:(id)sender withEvent:(UIEvent *)event

...事件总是以零返回！问题似乎发生在sendActionsForControlEvents中：

... the event always comes back as nil! The problem seems to occur within sendActionsForControlEvents:

现在，我需要我的IBAction才能确定触摸的位置。我通常是通过从事件中提取触摸来实现的。当然必须有某种方法来确保交付正确的事件？这是使用UIControl的一个非常基本的部分！

Now, I need my IBAction to be able to determine the location of the touch. I usually do so by extracting the touches from the event. Surely there must be some way to ensure that the correct event is delivered? It's a pretty fundamental part of using a UIControl!

任何人都知道合法的解决方法吗？

Anyone know a legal workaround?

推荐答案

我认为这是因为 sendActionsForControlEvents：方法无法知道哪个 UIEvent （如果有的话）你的控制事件应该与之相关联。

I would assume that this is because the sendActionsForControlEvents: method can't know which UIEvent (if any) your control event should be associated with.

你可以尝试单独发送所有动作（复制 sendActionsForControlEvents：方法，根据文档），所以你可以专门将它们与 UIEvent 相关联：

You could try to send all the actions separately (replicating what the sendActionsForControlEvents: method does, according to the documentation), so you can specifically associate them with a UIEvent:

UIEvent *event = ...;
UIControlEvents controlEvent = ...;

for (id target in [self allTargets]) {
    NSArray *actions = [self actionsForTarget:target forControlEvent:controlEvent];
    for (NSString *action in actions) {
        [self sendAction:NSSelectorFromString(action) to:target forEvent:event];
    }
}

这篇关于UIControl：sendActionsForControlEvents省略了UIEvent的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！