在iOS中，是否可以通过alloc和initWithFrame添加UIButton？ [英] In iOS, can a UIButton be added by alloc and initWithFrame?

问题描述

可以通过以下方式添加按钮：

A button can be added by:

UIButton *myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
myButton.frame = CGRectMake(100, 100, 160, 50);
[myButton setTitle:@"click me" forState:UIControlStateNormal];
[self.view addSubview:myButton];

但是我们可以使用 initWithFrame 方法吗：

but can we go with the initWithFrame method:

UIButton *myButton2 = [[UIButton alloc] initWithFrame:CGRectMake(100, 300, 160, 50)];
//myButton2.buttonType = UIButtonTypeRoundedRect;
myButton2.titleLabel.text = @"click me";
[self.view addSubview:myButton2];

但上面的第2行已被注释掉，因为它会导致只读属性出错，并且注释掉该行，仍然根本没有按钮...如果使用 initWithFrame 开头可以添加UIButton吗？

but line 2 above is commented out because it causes an error for a "read only" property, and with that line commented out, still no button shows up at all... can a UIButton be added if using initWithFrame to begin with?

（更新：我设置了黄色背景以查看视图区域，发现按钮2的标签文本实际上显示为单击我为白色...但是触摸它没有视觉效果...所以我想知道如何更改代码示例2使其起作用...）

(update: I set a yellow background to see the view's area, and found that the label text of button 2 actually shows up as "click me" in white... but touching it has no visual effect... so I wonder how to change code sample 2 to make it work...)

推荐答案

是的，当然可以。不久前，我就该readonly buttonType属性进行了一些讨论。普遍的共识是，任何人都没有安全的方法，也没有充分的理由来切换按钮的类型。此外， + buttonWithType 返回UIButton的实例以及 + Alloc 和- init 做，所以这不是问题。

Yes of course it can. I got into a little bit of a discussion as to that readonly buttonType property a while back. The general concensus is that there is neither a safe way, nor a good reason, for anyone to switch the type of a button. And besides, +buttonWithType returns an instance of UIButton just as well as +Alloc and -init do, so it isn't a problem.

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