IOS代码笔记UIView的placeholder的效果

时间:2021-05-20

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。

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