155，纯代码创建标签和按钮，并关联点击事件

#import "ViewController.h"

@interface
ViewController ()

@property(weak,nonatomic)
IBOutlet UIButton *btn;

@property(weak,nonatomic)
IBOutlet UILabel *label;

@end

@implementation ViewController

-(void)viewDidLoad{

[super
viewDidLoad];

//使用alloc init实例化的按钮，就是custom类型的，按钮的类型一旦指定，就不能修改

//UIButton *btn =[[UIButton alloc]initWithFrame:CGRectMake(100, 100, 199, 100)];

UIButton *btn = [UIButton
buttonWithType:UIButtonTypeCustom];

self.btn = btn;

//添加点击事件

[btn addTarget:self
action:@selector(printPersonInfo:)
forControlEvents:UIControlEventTouchUpInside];

[btn setFrame:CGRectMake(100,
100, 100,
100)];

[btn setBackgroundImage:[UIImage
imageNamed:@"btn_01"]
forState:UIControlStateNormal];

[btn setBackgroundImage:[UIImage
imageNamed:@"btn_02"]
forState:UIControlStateHighlighted];

[btn setTitle:@"点我"
forState:UIControlStateNormal];

[btn setTitle:@"别点我"
forState:UIControlStateHighlighted];

[btn setTitleColor:[UIColor
redColor] forState:UIControlStateNormal];

[btn setTitleColor:[UIColor
greenColor] forState:UIControlStateHighlighted];

btn.contentVerticalAlignment =
UIControlContentVerticalAlignmentBottom;

[self.view
addSubview:btn];

UILabel *label = [[UILabel
alloc]initWithFrame:CGRectMake(100,
300, 300,
50)];

self.label = label;

[self.view
addSubview:label];

}

-(IBAction)printPersonInfo:(UIButton *)button{

self.label.text
= @"我是JS，喜欢编程！";

}

@end