首页 / 移动开发 / IOS / IOS代码笔记UIView的placeholder的效果

 
二、工程图

 
三、代码
RootViewController.h

#import <UIKit/UIKit.h>@interface RootViewController : UIViewController<UITextViewDelegate>{UITextView *psTextView;UILabel *pslabel;}@end 

#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:@"
"]） {[textView resignFirstResponder];return NO;}return YES;}