UITextView*textView = [[UITextViewalloc] initWithFrame:CGRectMake(20,100, [UIScreenmainScreen].bounds.size.width-20,120];   

 [textView setBackgroundColor:[UIColor greenColor]];  

  [self.view addSubview:textView];

UILabel*placeHolderLabel = [[UILabelalloc] init];  

  placeHolderLabel.text =@"请输入建议或意见";   

 placeHolderLabel.numberOfLines =0;  

  placeHolderLabel.textColor = [UIColorlightGrayColor];   

 [placeHolderLabel sizeToFit]; 

   [textView addSubview:placeHolderLabel];

fonttextView.font = [UIFontsystemFontOfSize:12];  

  placeHolderLabel.font = [UIFontsystemFontOfSize:12];  

  [textView setValue:placeHolderLabel forKey:@"_placeholderLabel"];