iOS bringSubviewToFront和exchangeSubviewAtIndex方法应用

 联系人:石虎  QQ: 1224614774 昵称:嗡嘛呢叭咪哄

-(void)viewWillAppear:(BOOL)animated {

    [super viewWillAppear:animated];

    self.view.backgroundColor = [UIColor whiteColor];

 

#warning 效果图一:

    //懒加载，将切换城市按钮拿到最上层

   [self.view bringSubviewToFront:self.changeCityBtn];// 将子视图在前面

  

#warning 效果图二:    

    //用第二层子视图 换 第一层子视图的位置,self.view是第0层

    //[self.view exchangeSubviewAtIndex:2 withSubviewAtIndex:1];

  

}

 

//changeCityBtn getter 方法实现

-(UIButton *)changeCityBtn {

    if (!_changeCityBtn) {

        _changeCityBtn = [UIButtonbuttonWithType:UIButtonTypeCustom];

        _changeCityBtn.frame = CGRectMake(kScreenWidth-44-10,20, 44, 44);

        _changeCityBtn.imageEdgeInsets = UIEdgeInsetsMake(8, 8,8, 8);

        [_changeCityBtn setImage:[UIImageimageNamed:@"location_hardware"]forState:UIControlStateNormal];

        [self.view addSubview:_changeCityBtn];

        [_changeCityBtn addTarget:selfaction:@selector(changeCity)forControlEvents:UIControlEventTouchUpInside];        

    }    

    return _changeCityBtn;

}