我试图让我的Inputview的背景保持透明，但我只把它变成灰色。代码是:letfakeField:UITextField=UITextField(frame:CGRect.zero)//1InputViewCollection=InputView(frame:CGRect(x:0,y:0,width:0,height:216))//IntializecustominputviewInputViewCollection?.delegate=self//delegateInputViewCollection?.dataSource=self//datasource//2InputView