Upputton的titleLabel.text未显示在Cocoa Touch上

Question

在运行时创建新的UIButton并设置其titleLabel的文本后，按钮的文本仍未显示。

我做错了什么？

-(IBAction) cloneMe: (id) sender{

    if (!currentY) {
        currentY = [sender frame].origin.y;
    }

    UIButton *clone = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    CGRect cloneFrame = [sender frame];
    cloneFrame.origin.y += currentY + cloneFrame.size.height + 30;
    clone.frame = cloneFrame;
    [clone titleLabel].text = @"I'm a clone";

    [[sender superview] addSubview:clone];

    currentY = cloneFrame.origin.y + cloneFrame.size.height;


}

Answer 1

你需要：

[clone setTitle:@"I'm a clone" forState:UIControlStateNormal];

查看UIControl API文档，了解forState:参数的其他有效值。

Answer 2

使用setTitle:forState:设置按钮的标题。