Snail—UI学习之得到某组件的方法

第一种方法：依据传入函数的參数对象的tag属性区分

比方 多个button运行同一个方法，可是不同的方法运行时。里面的逻辑又不一样 那就得加以区分 这时能够用tag来差别

//再新建一个Button
    UIButton * button2 = [UIButton buttonWithType:UIButtonTypeSystem];
    button2.frame = CGRectMake(20, 60, 280, 30);
    button2.tag = 2;
    button2.backgroundColor = [UIColor redColor];
    [button2 setTitle:@"点我2" forState:UIControlStateNormal];
    //此action中得click:是代表有參数的click方法
    [button2 addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button2];
    
    //自己定义按钮  UIButtonTypeCustom
    UIButton * button3 = [UIButton buttonWithType:UIButtonTypeCustom];
    button3.frame = CGRectMake(20, 100, 31, 30);
    
    [button3 setTitle:@"点我3" forState:UIControlStateNormal];
    button3.tag = 3;
    //设置button的初始状态  已经选择的状态
    button3.selected = NO;
    //设置自己定义按钮两种状态下得不同图片
    //未选中状态显示的是第一个图片 选中状态后是后边的一个图片
    [button3 setImage:[UIImage imageNamed:@"star_icon@2x.png"] forState:UIControlStateNormal];
    
    [button3 setImage:[UIImage imageNamed:@"star2_Gray@2x.png"] forState:UIControlStateSelected];
    [button3 addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button3];
    
}


//假设有多个按钮要触发同一个操作,可是又想实现不同按钮方法将运行不同操作时，就要推断一下是哪个按钮按下了
- (void)click:(UIButton *)button{
    if (button.tag == 2) {
        NSLog(@"button2 点我了");
    }else if (button.tag == 3){
        NSLog(@"button3 点我了");
    }
}

#import "WJJRootViewController.h"

@interface WJJRootViewController (){
    <span style="color:#FF0000;">//为全局变量 在此类的不论什么地方都能够得到此对象
    UIButton * _button3;</span>
}

@end

@implementation WJJRootViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

UIButton * btn = (UIButton *)[self.view viewWithTag:3];