iOS－target－action设计模式了解

iOS－target－action设计模式了解

target－action的设计模式的本质就是在host中产生的事件调用target的action方法。

下面我们通过一个UIView来实现UIButton的点击事件。

@interface CustomButton : UIView
-(void)addCustomButton:(id)target andSelector:(SEL)action;
@end

@implementation CustomButton{
    id _target;
    SEL _action;
}

-(void)addCustomButton:(id)target andSelector:(SEL)action{
    if (target==_target) {
        return;
    }
    
    _target = target;
    _action = action;
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    if (_target) {
        if ([_target respondsToSelector:_action]) {
            [_target performSelector:_action withObject:self];
        }
    }
}

使用

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    CustomButton *btn = [[CustomButton alloc]initWithFrame:CGRectMake(0, 100, 200, 200)];
    btn.backgroundColor = [UIColor redColor];
    [btn addCustomButton:self andSelector:@selector(hello:)];
    [self.view addSubview:btn];
    
}

-(void)hello:(id)sender{
    NSLog(@"hello customer ");
}

运行结果

2015-03-29 17:09:03.803 Target_action[1863:89334] hello customer 

运行内存状态：