IOS代码笔记UIView的placeholder的效果

本文实例为大家分享了ios占位符效果，供大家参考，具体内容如下

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;
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。