给UITextView添加背景图片

UITextView *userNameText = [[UITextField  alloc]init];
//添加用户名文本框背景图片
UIImageView *userImgView=[[UIImageView alloc] initWithFrame:userNameText.bounds];
userImgView.image=[UIImage imageNamed:@"用户名、密码输入框.png"];
userImgView.contentMode = UIViewContentModeScaleToFill;
[userNameText  addSubview:userImgView];
//sendSubviewToBack 将该subview置于最底层
[userNameText sendSubviewToBack:userImgView];