簡易貼背景圖

若頁面整頁需要加背景圖，傳統做法如下:(123爲圖片名)

UIImageView *backImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, ScreenWidth, ScreenHeight)];
backImageView.image = [UIImage imageNamed:@"123"];
[self.view addSubview:backImageView];

get新技能：

self.view.layer.contents = (__bridge id _Nullable)([UIImage imageNamed:@"123"].CGImage);

哈哈。