ViewControlloer常用背景圖設置

@property(nonatomic,strong)UIImageView*bgImageView;

//背景圖
    _bgImageView = [[UIImageView alloc]initWithFrame:self.view.frame];
    _bgImageView.userInteractionEnabled = YES;
    _bgImageView.backgroundColor = [UIColor whiteColor];
    [self.view addSubview:_bgImageView];