TextField
[textFeild setValue:[UIColor WhiteColor] forKeyPath:@"placeholderLabel.textColor"];//设置占位字符颜色
[textFeild setValue:[UIFont systemFontOfSize:32] forKeyPath:@"placeholderLabel.font"];//设置占位字符大小
TextView(自动识别是否有内容显示和隐藏占位字符)
- (void)setupTextView
{
UILabel *placeHolderLabel = [[UILabel alloc] init];
placeHolderLabel.text = @"占位字符串内容";
placeHolderLabel.numberOfLines = 0;
placeHolderLabel.textColor = UIColor;
[placeHolderLabel sizeToFit];
[_addressTextView addSubview:placeHolderLabel];
_addressTextView.font = [UIFont systemFontOfSize:14.f];
placeHolderLabel.font = [UIFont systemFontOfSize:14.f];
[_addressTextView setValue:placeHolderLabel forKey:@"placeholderLabel"];
}