objective-c - iOS 从 viewcontroller.m 添加一个按钮

Question

所以，我一直在努力学习 iOS 的 Objective-C 编程的基础知识。现在我需要在框架中放置一个简单的按钮以及一个标签。我得到了标签，但我不确定按钮代码有什么问题。

编码：

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(25, 25, 275, 60)];
label.text = test;//@"I am learning Objective-C for the\n very first time!";
label.numberOfLines = 0;
label.lineBreakMode = UILineBreakModeWordWrap;
//label.lineBreakMode = NSLineBreakByWordWrapping; //iOS 6 only
[self.view addSubview:label];

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(25, 100, 275, 40)];
button.titleLabel.text = @"Hello";
[self.view addSubview:button];

按钮不显示...

Answer 1

创建按钮的典型方法是：

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [btn setTitle:@"Hello" forState:UIControlStateNormal];
    btn.frame = CGRectMake(25, 100, 275, 40);
    [btn addTarget:self action:@selector(someMethod:) forControlEvents:UIControlEventTouchUpInside];
    [self addSubview:btn];

那么someMeothod:将是：

- (void)someMethod:(UIButton *)sender {
    // handle button press
}

Answer 2

点表示法可能有问题。使用它来设置标题：

    [button setTitle:@"myTitle" forState:UIControlStateNormal];

Answer 3

试试这个：

 UIButton *myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
myButton.frame=CGRectMake(0, 0, 40, 30);
[myButton setTitle:@"normal" forState:UIControlStateNormal];
[myButton setTitle:@"selected" forState:UIControlStateSelected];
myButton.titleLabel.textColor=[UIColor blackColor];
[self.view addSubview:myButton];