ios - 如何修复 UIButton 的 sizeToFit/sizeThatFit 的宽度？

Question

我发现 sizeToFit 或 sizeThatFits 会改变UIButton当前的宽度。

UIButton* btn = [UIButton buttonWithType:UIButtonTypeCustom];
btn.frame = CGRectMake(100, 100, 200, 40);
btn.backgroundColor = [UIColor redColor];
[btn.titleLabel setText:@"ssdkfjsakdfjsakfjaksdjfkasjfkasjkfasjkfsajfkasjkas"];
btn.titleLabel.numberOfLines = 0;
[btn setTitle:@"ssdkfjsakdfjsakfjaksdjfkasjfkasjkfasjkfsajfkasjkas" forState:UIControlStateNormal];
[self.view addSubview:btn];

NSLog(@"before sizeToFit: %@",NSStringFromCGRect(btn.frame));
CGSize size = [btn sizeThatFits:CGSizeMake(200, 1000)];
[btn sizeToFit];

NSLog(@"after sizeToFit:%@",NSStringFromCGRect(btn.frame));
NSLog(@" sizeThatFits:%@",NSStringFromCGSize(size));

输出将是：

before sizeToFit: {{100, 100}, {200, 40}}
after sizeToFit:{{100, 100}, {392, 34}}
sizeThatFits:{392, 34}

这不是我想要的行为，如果我希望 sizeToFit 根据其原点宽度将按钮框架调整到适当的高度。如何做到这一点？

Answer 1

如果要更改 sizeToFit 设置的尺寸，则需要重写 sizeThatFits 方法。创建一个子类UIButton如下：

迅速：

class MyButton: UIButton {
    override func sizeThatFits(_ size: CGSize) -> CGSize {
        let sizeThatFits = super.sizeThatFits(size)
        return CGSize(width: sizeThatFits.width, height: self.frame.height)
    }
}

目标 C：

@implementation MyButton

- (CGSize)sizeThatFits:(CGSize)size {
    CGSize sizeThatFits = [super sizeThatFits:size];
    return CGSizeMake(sizeThatFits.width, self.frame.size.height);
}

@end

并使用子类按钮而不是 UIButton。

UIButton* btn = [MyButton buttonWithType:UIButtonTypeCustom];

参考：Apple Doc：sizeToFit