Xcode单选按钮-按下另一个按钮时更改按钮的背景图像 [英] Xcode radio buttons- Changing background image of a button when another button is pressed

问题描述

我正在尝试实现我自己的基本单选按钮，以便一次只能选择其中一个.这是我正在使用的代码->

I'm trying to implement my own basic radio buttons, such that only one of them can be selected at a time. Here's the code I'm using->

- (IBAction)btn2Pressed:(UIButton *)sender {
    [btn1 setBackgroundImage:[UIImage imageNamed:@"circle-uncheck.png"] forState:UIControlStateNormal];
    btn2pressed = YES;
    btn1pressed = NO;
}


- (IBAction)btn1Pressed:(UIButton *)sender {
    [btn2 setBackgroundImage:[UIImage imageNamed:@"circle-uncheck.png"] forState:UIControlStateNormal];
    btn1pressed = YES;
    btn2pressed = NO;
}

但它不起作用，即另一个按钮的图像没有改变.:(

But it's not working, i.e. the image of the other button isn't changing. :(

我不知道自己做错了什么.

I'm not able to figure out what I'm doing wrong.

推荐答案

当您按下 2 个按钮中的任何一个时，您将背景图像设置为 circle-uncheck.png.它是如何更改为 checked 的?我猜它会永远保持unchecked.

When you press any of the 2 buttons, you set the background image to circle-uncheck.png. How is it ever be changed to checked? It will stay unchecked forever, I guess.

编辑(由于您在下面的评论):

EDIT (due to you comment below):

如果您在界面生成器中最初设置背景图像，它们将在按下按钮后立即更改为circle-uncheck.png，并且它们是显然永远不会设置为 checked 状态.
您必须将代码修改为类似

If you set the background images initially in the Interface Builder, they will be changed to circle-uncheck.png as soon as a button is pushed, and they are apparently never be set to the checked state.
You had to modify your code to something like

- (IBAction)btn2Pressed:(UIButton *)sender {
    [btn1 setBackgroundImage:[UIImage imageNamed:@"circle-uncheck.png"] forState:UIControlStateNormal];
    [btn2 setBackgroundImage:[UIImage imageNamed:@"circle-check.png"] forState:UIControlStateNormal];
    btn2pressed = YES;
    btn1pressed = NO;
}

- (IBAction)btn1Pressed:(UIButton *)sender {
    [btn2 setBackgroundImage:[UIImage imageNamed:@"circle-uncheck.png"] forState:UIControlStateNormal];
    [btn1 setBackgroundImage:[UIImage imageNamed:@"circle-check.png"] forState:UIControlStateNormal];
    btn1pressed = YES;
    btn2pressed = NO;
}

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