Question

我的viewcontroller中有一个自定义UIButton，它应该具有红色或蓝色心脏的图像，具体取决于加载viewcontroller时变量的值。如果用户单击该按钮，则会更改域模型中的红/蓝值，还应切换按钮图像。如果我在ViewWillAppear中调用以下代码，则按钮颜色将正确加载：

if ([self.color isBlue])
     self.colorButton.imageview.image = [UIImage imageNamed:@"blueHeart.png"];
else
     self.colorButton.imageview.image = [UIImage imageNamed:@"redHeart.png"];

但按下按钮时，我无法改变颜色。按下按钮时，我的toggleColor：action方法被调用：

- (IBAction)toggleColor:(id)sender
{
    if ([self.color isBlue])
    {
        [self.color makeRed];
        self.colorButton.imageView.image = [UIImage imageNamed:@"redHeart.png"];
    }       

    else 
    {
        [self.color makeBlue];
        self.colorButton.imageView.image = [UIImage imageNamed:@"blueHeart.png"];
    }
}

值在color变量中应更新，但按钮的颜色不会改变。（我已经在调试器中验证了所有代码行都按原样执行。）我尝试使用[button setImage: forState:]和[button setBackgroundImage: forState:]，但它们的行为并不像预期的那样。请问有人请告诉我ViewWillAppear :(或ViewDidLoad :)方法和我的toggleColor：方法的步骤？我在这里错过了一些东西。

Answer 1

这对我有用：

- (void) viewDidLoad {     
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    button.frame = CGRectMake(50, 40, 30, 30);
    [button setImage:[UIImage imageNamed:@"red.png"] forState:UIControlStateNormal];
    [button setImage:[UIImage imageNamed:@"blue.png"] forState:UIControlStateSelected];
    [button addTarget:self action:@selector(toggleButtonImages:) forControlEvents:UIControlEventTouchUpInside];     
    [self.view addSubview:button];
}

-(void) toggleButtonImages:(UIButton *)button {
    UIImage *temp = [button imageForState:UIControlStateNormal];
    [button setImage:[button imageForState:UIControlStateSelected] forState:UIControlStateNormal];
    [button setImage:temp forState:UIControlStateSelected];
}

UIButton图像/背景图像怪异

1 个答案: