TouchUpInside事件后无法将UIButton保持在选定状态

问题描述

我需要一个UIButton来保持按下状态.基本上，如果一个按钮处于正常状态，我想触摸该按钮，它将其突出显示为标准的蓝色，然后在举起手指后保持蓝色.我做了以下UIAction并将按钮Touch Up Inside事件连接到它.

I have the need for an UIButton to maintain a pressed state. Basically, if a button is in a normal state, I want to touch the button, it highlight to its standard blue color and then stay blue after lifting my finger.I made the following UIAction and connected the buttons Touch Up Inside event to it.

-(IBAction) emergencyButtonPress:(id) sender
{
    if(emergencyButton.highlighted)
    {
        emergencyButton.selected = NO;
        emergencyButton.highlighted = NO;
    }
    else
    {
        emergencyButton.selected = YES;
        emergencyButton.highlighted = YES;
    }
}

但是发生了什么，当我松开手指后，按钮又回到了白色背景.为了进行测试，我添加了一个UISwitch并让它执行相同的代码:

But what happens, after I remove my finger, the button goes back to a white background. For a test I added a UISwitch and have it execute the same code:

-(IBAction) emergencySwitchClick:(id) sender
{
    if(emergencyButton.highlighted)
    {
        emergencyButton.selected = NO;
        emergencyButton.highlighted = NO;
    }
    else
    {
        emergencyButton.selected = YES;
        emergencyButton.highlighted = YES;
    }
}

在这种情况下，按钮会像我期望的那样切换到突出显示和未突出显示的状态.

In this case the button toggles to a highlighted and non-highlighted state as I would expect.

在"Touch Up Inside"事件之后是否发生了另一个事件，该事件将状态重置为正常"?如何保持突出显示状态?

Is there another event happening after the Touch Up Inside event that is resetting the state back to 'normal'? How do I maintain the highlighted state?

推荐答案

当您触摸/释放按钮时，iOS将应用并删除突出显示的状态.因此，不要在您的操作方法中依赖它.

The highlighted state is applied and removed by iOS when you touch / release the button. So don't depend on it in your action method.

如其他答案之一所述，将突出显示的图像设置为与所选图像相同，然后修改您的操作方法:

As one of the other answers says, set the highlighted image to be the same as the selected image, and then modify your action method:

-(IBAction) emergencyButtonPress:(id) sender
{
    emergencyButton.selected = !emergencyButton.selected;
}

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