1.安装Masonry库
pod 'Masonry'

2.导入Masonry

import <Masonry/Masonry.h>

3.使用

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    UIButton *btn = [[UIButton alloc] init];
    btn.backgroundColor = [UIColor redColor];
    [self.view addSubview:btn];
    [btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    
    [btn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(self.view).with.mas_offset(10);
        make.right.mas_equalTo(self.view).with.mas_offset(-10);
        make.top.mas_equalTo(self.view).with.mas_offset(100);
        make.height.mas_equalTo(@100);
    }];
}


- (void)btnClick:(UIButton *)btn {
    
    [UIView animateWithDuration:3 animations:^{
        [btn mas_updateConstraints:^(MASConstraintMaker *make) {
            make.height.mas_equalTo(@300);
        }];
        [self.view layoutIfNeeded];
    }];

}

完毕。