如何正确地继承UIControl？ [英] How to correctly subclass UIControl?

问题描述

我不想要 UIButton 或类似的东西。我想直接子化 UIControl 并制作我自己的非常特殊的控件。

I don't want UIButton or anything like that. I want to subclass UIControl directly and make my own, very special control.

但由于某种原因，没有我覆盖的任何方法都会被调用。目标动作的东西起作用，目标接收适当的动作消息。但是，在我的 UIControl 子类中，我必须捕获触摸坐标，这样做的唯一方法似乎是覆盖这些人：

But for some reason, none of any methods I override get ever called. The target-action stuff works, and the targets receive appropriate action messages. However, inside my UIControl subclass I have to catch touch coordinates, and the only way to do so seems to be overriding these guys:

- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event {
    NSLog(@"begin touch track");
    return YES;
}

- (BOOL)continueTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event {
    NSLog(@"continue touch track");
    return YES;
}

他们从未被调用过，即使 UIControl 使用来自 UIView ， initWithFrame：的指定初始化程序进行实例化。

They get never called, even though the UIControl is instantiated with the designates initializer from UIView, initWithFrame:.

我能找到的所有例子总是使用 UIButton 或 UISlider 作为子类化的基础，但我想更接近 UIControl ，因为这是我想要的来源：快速和未延迟的触摸坐标。

All examples I can find always use a UIButton or UISlider as base for subclassing, but I want to go closer to UIControl since that's the source for what I want: Fast and undelayed Touch coordinates.

推荐答案

我知道这个问题很古老，但我遇到了同样的问题，我想我应该给出2美分。

I know this question is ancient, but I had the same problem and I thought I should give my 2 cents.

如果您的控件有任何子视图， beginTrackingWithTouch ， touchesBegan 等可能无法调用，因为这些子视图正在吞下触摸事件。

If your control has any subviews at all, beginTrackingWithTouch, touchesBegan, etc might not get called because those subviews are swallowing the touch events.

如果您不希望这些子视图处理触摸，您可以将 userInteractionEnabled 设置为否，因此子视图只是传递事件通过。然后你可以覆盖 touchesBegan / touchesEnded 并管理那里的所有动作。

If you don't want those subviews to handle touches, you can set userInteractionEnabled to NO, so the subviews simply passes the event through. Then you can override touchesBegan/touchesEnded and manage all your touches there.

希望这有帮助。

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