一，效果图。
二，工程图。
三，代码。
RootViewController.h
#import <UIKit/UIKit.h> @interface RootViewController : UIViewController
<UITextViewDelegate>
{
UITextView *psTextView;
UILabel *pslabel;
}
@end
RootViewController.m
#import "RootViewController.h" @interface RootViewController () @end @implementation RootViewController - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
} - (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view. self.title=@"UIView的placeholder的效果"; [self initBackgroundView]; }
#pragma -mark -初始化背景图
-(void)initBackgroundView
{
UIView *backView=[[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)];
[self.view addSubview:backView]; psTextView=[[UITextView alloc]initWithFrame:CGRectMake(10, 70, 280, 200)];
psTextView.text=@"";
psTextView.backgroundColor=[UIColor yellowColor];
psTextView.delegate=self;
psTextView.scrollEnabled=NO;
[backView addSubview:psTextView]; pslabel=[[UILabel alloc]initWithFrame:CGRectMake(15, 140, 280, 20)];
pslabel.text=@"请输入备注信息";
pslabel.textColor=[UIColor grayColor];
pslabel.enabled=NO;
pslabel.backgroundColor=[UIColor clearColor];
[backView addSubview:pslabel]; }
#pragma -mark -UITextView Delegate
- (BOOL)textViewShouldBeginEditing:(UITextView *)textView
{
return YES;
}
-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{ if (text.length>0) {
pslabel.hidden=YES;
} if ([text isEqualToString:@"\n"]) {
[textView resignFirstResponder];
return NO;
} return YES;
}