Block的示例学习

@interface ViewController ()


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



- (IBAction)reset:(id)sender;
- (IBAction)run:(id)sender;
- (IBAction)rotate:(id)sender;
- (IBAction)scale:(id)sender;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    

}

//定义函数,参数是block类型 无返回值,无参数的block

- (void)btnClickWithBlock:(void (^)())block
{
    // 0.动画（头部-开始动画）
    [UIView beginAnimations:nil context:nil];
    // 设置动画的执行时间
    [UIView setAnimationDuration:1.0];
    
    //block的调用
    block();
    
    // 1.动画（尾部-提交动画-执行动画）
    [UIView commitAnimations];
}



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


//重置
- (IBAction)reset:(id)sender {
    
    [self btnClickWithBlock:^{
        _btn.transform = CGAffineTransformIdentity;
    }];
}



//行走
- (IBAction)run:(id)sender {
    
    [self btnClickWithBlock:^{
        
        NSLog(@"self = %@",self);   //表示此控制器
        
        // 1.先取出frame
        CGPoint tempCenter = _btn.center;
        
        // 2.取出按钮的tag标记
        NSInteger tag = [sender tag];
        
        switch (tag) {
            case 10:
                
                tempCenter.y -= kDelta;
                
                break;
                
            case 20:
                
                tempCenter.x -= kDelta;
                break;
                
            case 30:
                
                tempCenter.y += kDelta;
                break;
                
                
            case 40:
                
                tempCenter.x += kDelta;
                break;
                
                
            default:
                break;
        }
        
        // 3.重新赋值按钮的frame
        _btn.center = tempCenter;
        
        
        
    }];
}

//旋转
- (IBAction)rotate:(id)sender {
    
    [self btnClickWithBlock:^{
        NSInteger tag = [sender tag];
        if (10 == tag) { // 左
            _btn.transform = CGAffineTransformRotate(_btn.transform, M_PI_4 * -1);
        } else { // 右
            _btn.transform = CGAffineTransformRotate(_btn.transform, M_PI_4 * 1);
        }
    }];
    
}

//缩放
- (IBAction)scale:(id)sender {
    
    [self btnClickWithBlock:^{
        CGFloat scale = [sender tag] == 20 ? 1.2 : 0.8;
        _btn.transform = CGAffineTransformScale(_btn.transform, scale, scale);
    }];
    
    
}