如何传递多个值到@selector（）UIButton？ [英] How to pass multiple values into @selector( ) for a UIButton?

问题描述

换句话说：我有一个按钮有两个事件，如何在回调中捕获 UIControlEventTouchDown 和 UIControlEventTouchUpInside 函数 setRedPos ？

In other words: I have one button with two events, how to capture UIControlEventTouchDown and UIControlEventTouchUpInside in the callback function setRedPos?

[btnRedPos addTarget:self action:@selector(setRedPos:) forControlEvents:UIControlEventTouchDown];// I want to pass in a value of 0
[btnRedPos addTarget:self action:@selector(setRedPos:) forControlEvents:UIControlEventTouchUpInside];// I want to pass in a value of 1

...

- (void) setRedPos:(UIButton*)btn
{

}

推荐答案

不能通过target / action传递任意参数。第一个参数是sender，第二个（如果你这样设置）是事件。你可以使用事件来告诉它是什么类型的事件触发它，像这样：

You can't pass arbitrary parameters via target/action. The first parameter is sender, and the second (if you set it up this way) is the event. You could use the event to tell what kind of event triggered it, like so:

[btnRedPos addTarget:self action:@selector(setRedPos:forEvent:) 
    forControlEvents:UIControlEventTouchDown];
[btnRedPos addTarget:self action:@selector(setRedPos:forEvent:) 
    forControlEvents:UIControlEventTouchUpInside];


- (void) setRedPos:(id)sender forEvent:(UIEvent*)event
{
    UITouch* aTouch = [[event allTouches] anyObject];
    if( aTouch.phase == UITouchPhaseBegan ) {
        NSLog( @"touch began" );
    }
    else if( aTouch.phase == UITouchPhaseEnded ) {
        NSLog( @"touch ended" );
    }
}

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