02-动态创建按钮

在ViewController.m文件中：

viewDidLoad：被系统调用，调用时机：加载View Controll完毕之后

// 这是控制器的一个方法：当控制器的view创建完毕的时候调用一次
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    // 1.创建按钮
    // 1.1创建
    UIButton *btn = [[UIButton alloc] init];
    NSLog(@"btn -- %p", btn);
    
    // 1.2设置按钮的尺寸和位置
    btn.frame = CGRectMake(0, 0, 100, 100);
    
    // 1.3设置按钮普通状态下的属性
    // 1.3.1设置背景图片
    UIImage *normal = [UIImage imageNamed:@"btn_01.png"];
    [btn setBackgroundImage:normal forState:UIControlStateNormal];
    
    // 1.3.2设置文字
    [btn setTitle:@"点我咯" forState:UIControlStateNormal];
    
    // 1.3.3设置文字颜色
    [btn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    
    // 1.4设置按钮高亮状态下的属性
    // 1.4.1设置背景图片
    UIImage *high = [UIImage imageNamed:@"btn_02.png"];
    [btn setBackgroundImage:high forState:UIControlStateHighlighted];
    
    // 1.4.2设置文字
    [btn setTitle:@"摸我干啥" forState:UIControlStateHighlighted];
    
    // 1.4.3设置文字颜色
    [btn setTitleColor:[UIColor greenColor] forState:UIControlStateHighlighted];
    
    // 1.5监听按钮点击
    [btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    
    // 1.6增加到view中
    [self.view addSubview:btn];
    
    UITextField *txt = [[UITextField alloc] init];
    txt.frame = CGRectMake(100, 100, 100, 50);
    CGFloat centerX = self.view.frame.size.width*0.5;
    CGFloat centerY = self.view.frame.size.height*0.5;
    txt.center = CGPointMake(centerX, centerY);
    txt.backgroundColor = [UIColor redColor];
    [txt setText:@"默认文本值"];
    [txt setFont:[UIFont boldSystemFontOfSize:20]];
    
    [self.view addSubview:txt];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)btnClick:(UIButton *)btn
{
    NSLog(@"btnClick -- %p", btn);
 
}

1.添加控件到控制器的view
[self.view addSubView:子控件];

2.监听按钮点击
[btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];