前言

公司業(yè)務(wù)需要，PC端，移動(dòng)端都用到了第三方 網(wǎng)易云信 IM 來實(shí)現(xiàn)在線客服咨詢媒怯。
在這當(dāng)中難免遇到一些需求是網(wǎng)易云信沒有提供鸽嫂，需要自行編碼進(jìn)行擴(kuò)展的纵装。寫此篇文章的目的正是因業(yè)務(wù)需要，需要在網(wǎng)易云信的基礎(chǔ)上進(jìn)行消息類型的擴(kuò)展据某。

此篇文章里的代碼是基于 網(wǎng)易云信 NIM_iOS_Demo_v4.5.0 版 進(jìn)行修改的

如下圖所示的消息類型

帶圖片和文字橡娄，并且可點(diǎn)擊的消息類型，（注意收到的消息和發(fā)送的消息文本顏色不一樣）

標(biāo)題是iOS版癣籽，可想而知挽唉，肯定還有其他如 Android版，Web版等筷狼，不可能此類型的消息（我稱它為圖文消息）只支持iOS瓶籽，而在Android或Web端無法顯示問題。以下附上其他版本擴(kuò)展的鏈接

• 網(wǎng)易云信-新增自定義消息（Android版）
• 網(wǎng)易云信-新增自定義消息（Web版）
• 網(wǎng)易云信-新增自定義消息（H5移動(dòng)版）

正文

1. 下載demo后埂材，雙擊 NIMDemo/NIM.xcworkspace 打開項(xiàng)目塑顺，然后運(yùn)行，確保下載下來的demo能正確運(yùn)行起來俏险。

2. 運(yùn)行沒有問題后严拒，修改以下幾個(gè)文件配置，將demo修改為自己所用竖独。

   • 修改 Classes/Util/NTESDemoConfig.m 中的_appKey裤唠，填入自己的appKey

- (instancetype)init
{
    if (self = [super init])
    {
        _appKey = @"填入自己的appKey";
        _apiURL = @"https://app.netease.im/api";
        _apnsCername = @"ENTERPRISE";
        _pkCername = @"DEMO_PUSH_KIT";
        
        _redPacketConfig = [[NTESRedPacketConfig alloc] init];        
    }
    return self;
}

• 修改

- (NSString *)tokenByPassword
{
    //demo直接使用username作為account，md5(password)作為token
    //接入應(yīng)用開發(fā)需要根據(jù)自己的實(shí)際情況來獲取 account和token
    //return [[NIMSDK sharedSDK] isUsingDemoAppKey] ? [self MD5String] : self;
    return [self MD5String];
}

修改上述代碼后莹痢，重新運(yùn)行种蘸，即可使用自己的賬號(hào)密碼登錄了。

3. 添加測(cè)試發(fā)送圖文鏈接的按鈕竞膳，點(diǎn)擊即發(fā)送圖文鏈接消息

編輯NTESCellLayoutConfig.m文件航瞭，在init函數(shù)中 _types 增加一條

- (instancetype)init
{
    if (self = [super init])
    {
        _types =  @[
                   @"NTESJanKenPonAttachment",
                   @"NTESSnapchatAttachment",
                   @"NTESChartletAttachment",
                   @"NTESWhiteboardAttachment",
                   @"NTESRedPacketAttachment",
                   @"NTESRedPacketTipAttachment",
                   // 添加圖文鏈接消息
                   @"NTESLinkAttachment"
                   ];
        _sessionCustomconfig = [[NTESSessionCustomContentConfig alloc] init];
        _chatroomTextConfig  = [[NTESChatroomTextContentConfig alloc] init];
        _chatroomRobotConfig = [[NTESChatroomRobotContentConfig alloc] init];
    }
    return self;
}

編輯 NTESCustomAttachmentDecoder.m文件，checkAttachment函數(shù)中添加如下代碼

//頭部導(dǎo)入
#import "NTESLinkAttachment.h"
//...

- (id<NIMCustomAttachment>)decodeAttachment:(NSString *)content
{
    id<NIMCustomAttachment> attachment = nil;

    NSData *data = [content dataUsingEncoding:NSUTF8StringEncoding];
    if (data) {
        NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data
                                                             options:0
                                                               error:nil];
        if ([dict isKindOfClass:[NSDictionary class]])
        {
            NSInteger type     = [dict jsonInteger:CMType];
            NSDictionary *data = [dict jsonDict:CMData];
            switch (type) {
                //...
                // 添加圖文鏈接 case
                case CustomMessageTypeLink:
                {
                    attachment = [[NTESLinkAttachment alloc] init];
                    ((NTESLinkAttachment *)attachment).title        = [data jsonString:CMLinkPacketTitle];
                    ((NTESLinkAttachment *)attachment).linkUrl      = [data jsonString:CMLinkPacketLinkUrl];
                    ((NTESLinkAttachment *)attachment).imageUrl     = [data jsonString:CMLinkPacketImageUrl];
                    ((NTESLinkAttachment *)attachment).describe     = [data jsonString:CMLinkPacketDescribe];
                }
                    break;
                default:
                    break;
            }
            attachment = [self checkAttachment:attachment] ? attachment : nil;
        }
    }
    return attachment;
}

- (BOOL)checkAttachment:(id<NIMCustomAttachment>)attachment
{

    // ... 省略前面的 if  else if 塊
    
    // 添加如下代碼
    else if ([attachment isKindOfClass:[NTESLinkAttachment class]])
    {
        check = YES;
    }
    return check;
}

編輯NTESSessionConfig.m文件顶猜，在mediaItems函數(shù)中添加如下代碼

//...
// 添加圖文鏈接測(cè)試按鈕沧奴，此處的 onTapMediaItemLinkPacket 在
 NTESSessionViewController.m 中添加 
NIMMediaItem *linkPacket  = [NIMMediaItem item:@"onTapMediaItemLinkPacket:"
                                   normalImage:[UIImage imageNamed:@"icon_redpacket_normal"]
                                 selectedImage:[UIImage imageNamed:@"icon_redpacket_pressed"]
                                         title:@"圖文鏈接"];
//...
if (isMe)
{
    items = @[janKenPon,fileTrans,tip];
}
else if(_session.sessionType == NIMSessionTypeTeam)
{
    // 在群組消息里添加
    items = @[janKenPon,teamMeeting,fileTrans,tip,redPacket,linkPacket];
}
else
{
    // 添加圖文鏈接測(cè)試按鈕
    items = @[janKenPon,audioChat,videoChat,fileTrans,snapChat,whiteBoard,tip,redPacket,linkPacket];
}

在 Classes/Sections/Session/Object/Attach 目錄下創(chuàng)建 NTESLinkAttachment文件痘括，繼承 NSObject 類长窄，實(shí)現(xiàn) NIMCustomAttachment,NTESCustomAttachmentInfo 協(xié)議

創(chuàng)建Cocoa Touch Class文件 NTESLinkAttachment，命名規(guī)則盡量遵循云信命名規(guī)則

創(chuàng)建完成后纲菌，添加響應(yīng)的屬性值 標(biāo)題title挠日，跳轉(zhuǎn)的鏈接linkUrl，圖片imageUrl翰舌，描述describe嚣潜。

NTESLinkAttachment.h 文件內(nèi)容如下

#import <Foundation/Foundation.h>
#import "NTESCustomAttachmentDefines.h"

@interface NTESLinkAttachment : NSObject<NIMCustomAttachment,NTESCustomAttachmentInfo>

// 標(biāo)題
@property (nonatomic, copy) NSString *title;

// 點(diǎn)擊跳轉(zhuǎn)的鏈接地址
@property (nonatomic, copy) NSString *linkUrl;

// 圖片
@property (nonatomic, copy) NSString *imageUrl;

// 描述
@property (nonatomic, copy) NSString *describe;

@end

NTESLinkAttachment.m文件內(nèi)容如下

復(fù)制之后，會(huì)有報(bào)錯(cuò)如 NTESSessionLinkContentView.h 找不到椅贱，和 CMLinkPacket***未定義等相關(guān)錯(cuò)誤懂算，先別急只冻，后面會(huì)講到，如果看不順眼可以先注釋掉计技，回頭再過來放開注釋也行喜德。（ps：本人非iOS開發(fā)，所以代碼部分不做詳細(xì)講解）

#import "NTESLinkAttachment.h"
#import "NTESSessionLinkContentView.h"

@implementation NTESLinkAttachment

- (NSString *)encodeAttachment
{
    NSDictionary *dict = @{
                           CMType : @(CustomMessageTypeRedPacket),
                           CMData : @{
                              CMLinkPacketTitle    : self.title,
                              CMLinkPacketLinkUrl  : self.linkUrl,
                              CMLinkPacketImageUrl : self.imageUrl,
                              CMLinkPacketDescribe : self.describe
                           }
                       };
    NSData *data = [NSJSONSerialization dataWithJSONObject:dict
                                                   options:0
                                                     error:nil];
    NSString *content = nil;
    if (data) {
        content = [[NSString alloc] initWithData:data
                                        encoding:NSUTF8StringEncoding];
    }
    return content;
}


- (NSString *)cellContent:(NIMMessage *)message{
    return @"NTESSessionLinkContentView";
}

- (CGSize)contentSize:(NIMMessage *)message cellWidth:(CGFloat)width{
    CGFloat w = 240.0f;
    CGFloat h = 40.0f;
    CGFloat padding = 3.0f * 3;
    if (self.imageUrl != nil) {
        h += 140.f;
    }
    if (self.describe != nil) {
        UIFont *font = [UIFont systemFontOfSize:12.0];
        CGFloat height = [NTESSessionLinkContentView getHeightByWidth:w - padding title:self.describe font:font];
        h += height + padding;
    }
    
    return CGSizeMake(w, h);
}

- (UIEdgeInsets)contentViewInsets:(NIMMessage *)message
{
    CGFloat bubblePaddingForImage    = 3.f;
    CGFloat bubbleArrowWidthForImage = 5.f;
    if (message.isOutgoingMsg) {
        return  UIEdgeInsetsMake(bubblePaddingForImage,bubblePaddingForImage,bubblePaddingForImage,bubblePaddingForImage + bubbleArrowWidthForImage);
    }else{
        return  UIEdgeInsetsMake(bubblePaddingForImage,bubblePaddingForImage + bubbleArrowWidthForImage, bubblePaddingForImage,bubblePaddingForImage);
    }
}

- (BOOL)canBeRevoked
{
    return YES;
}

- (BOOL)canBeForwarded
{
    return YES;
}

@end

現(xiàn)在再來補(bǔ)充上面缺失的部分垮媒。
在 NTESCustomAttachmentDefines.h 文件中定義如下四個(gè)字段舍悯。打開這個(gè)文件可以看到這個(gè)里面還定義了一些其他消息需要用到的字段，所以遵循人家的游戲規(guī)則睡雇，也在此處定義萌衬。

//...省略

typedef NS_ENUM(NSInteger,NTESCustomMessageType){
    CustomMessageTypeJanKenPon  = 1, //剪子石頭布
    CustomMessageTypeSnapchat   = 2, //閱后即焚
    CustomMessageTypeChartlet   = 3, //貼圖表情
    CustomMessageTypeWhiteboard = 4, //白板會(huì)話
    // （由于我其他平臺(tái)圖文消息type是5，剛好我們業(yè)務(wù)不需要發(fā)紅包功能它抱，這里我只好把5變成我的圖文消息秕豫，把紅包類型的消息去除）
    CustomMessageTypeRedPacket  = 5, //紅包消息
    CustomMessageTypeRedPacketTip = 6, //紅包提示消息
};

//...省略


//紅包
#define CMRedPacketTitle   @"title"        //紅包標(biāo)題
#define CMRedPacketContent @"content"      //紅包內(nèi)容
#define CMRedPacketId      @"redPacketId"  //紅包ID
//紅包詳情
#define CMRedPacketSendId     @"sendPacketId"
#define CMRedPacketOpenId     @"openPacketId"
#define CMRedPacketDone       @"isGetDone"
// 添加此處四個(gè)字段用于圖文鏈接消息使用
#define CMLinkPacketTitle       @"title"        //標(biāo)題
#define CMLinkPacketLinkUrl     @"link_url"      //跳轉(zhuǎn)鏈接
#define CMLinkPacketImageUrl    @"image_url"     //圖片鏈接
#define CMLinkPacketDescribe    @"describe"     //描述
//...省略

在Classes/Sections/Session/View/SessionCell/SessionContentView目錄下創(chuàng)建Cocoach Touch Class文件 NIMSessionMessageContentView，此文件主要用來做圖文鏈接消息的顯示观蓄。

NIMSessionMessageContentView.h文件內(nèi)容如下

#import "NIMSessionMessageContentView.h"

static NSString *const NIMDemoEventNameLinkingPacket = @"NIMDemoEventNameLinkingPacket";

@interface NTESSessionLinkContentView : NIMSessionMessageContentView

// 根據(jù)寬度馁蒂，字體和文本內(nèi)容獲取高度
+ (CGFloat)getHeightByWidth:(CGFloat)width title:(NSString *)title font:(UIFont *)font;

@end

NIMSessionMessageContentView.m文件內(nèi)容如下

#import "NTESSessionLinkContentView.h"
#import "UIView+NTES.h"
#import "NTESLinkAttachment.h"
#import "NTESSessionUtil.h"
#import "UIImageView+WebCache.h"

CGFloat titleHeight = 40.f; // title高度
CGFloat imageHeight = 120.f;// 圖片高度

@interface NTESSessionLinkContentView()

// 圖文鏈接消息附件
@property (nonatomic,strong) NTESLinkAttachment *attachment;

@property (nonatomic,strong) UILabel *titleLabel;

@property (nonatomic,strong) UIImageView *imageView;

@property (nonatomic,strong) UILabel *describeLabel;

@end

@implementation NTESSessionLinkContentView

- (instancetype)initSessionMessageContentView{
    self = [super initSessionMessageContentView];
    if (self) {
        self.opaque = YES;
        
        _titleLabel = [[UILabel alloc] initWithFrame:CGRectZero];
        _imageView  = [[UIImageView alloc] initWithFrame:CGRectZero];
        _describeLabel = [[UILabel alloc] initWithFrame:CGRectZero];
    }
    return self;
}

- (void)refresh:(NIMMessageModel *)data
{
    [super refresh:data];
    NIMCustomObject *customObject = (NIMCustomObject*)data.message.messageObject;
    id attach = customObject.attachment;
    
    if ([attach isKindOfClass:[NTESLinkAttachment class]]) {
        self.attachment = (NTESLinkAttachment *)attach;
        
        self.titleLabel.text = self.attachment.title;
        [self addSubview:_titleLabel];
        
        if (self.attachment.imageUrl != nil) {
            NSURL *url = [NSURL URLWithString:self.attachment.imageUrl];
            // 默認(rèn)圖片 default_image，記得在 Images.xcassets 中添加
            [self.imageView sd_setImageWithURL:url placeholderImage:[UIImage imageNamed:@"default_image"]];
            [self.imageView sizeToFit];
            [self addSubview:_imageView];
        }
        if (self.attachment.describe != nil) {
            self.describeLabel.text = self.attachment.describe;
            [self addSubview:_describeLabel];
        }
    }
}

- (void)layoutSubviews{
    [super layoutSubviews];
    BOOL outgoing = self.model.message.isOutgoingMsg;
    
    UIEdgeInsets contentInsets = self.model.contentViewInsets;
    CGSize contentSize = [self.model contentSize:self.superview.width];
    CGFloat padding = 15;
    
    self.titleLabel.frame = CGRectMake(padding, contentInsets.left, contentSize.width - padding, titleHeight);
    self.titleLabel.font = [UIFont systemFontOfSize:14.0];
    self.titleLabel.numberOfLines = 1;
    
    // 詳情描述距離
    CGFloat describeY = titleHeight;
    
    if (self.attachment != nil && self.attachment.imageUrl != nil) {
        self.imageView.frame = CGRectMake(
                                          contentInsets.left + contentInsets.right,
                                          titleHeight + contentInsets.top + 5,
                                          contentSize.width - (contentInsets.left + contentInsets.right), imageHeight);
        self.imageView.contentMode = UIViewContentModeScaleAspectFit;
        [self setBorderWithImageView:self.imageView top:TRUE left:FALSE bottom:TRUE right:FALSE borderColor:[UIColor lightGrayColor] borderWidth:0.3f];
        describeY += imageHeight + contentInsets.top * 3 + 5 ;
    }
    
    if (self.attachment != nil && self.attachment.describe != nil) {
        UIFont *font = [UIFont systemFontOfSize:12.0];
        self.describeLabel.font = font;
        self.describeLabel.numberOfLines = 3;
        CGFloat height = [NTESSessionLinkContentView getHeightByWidth:self.describeLabel.frame.size.width title:self.attachment.describe font:font];
        self.describeLabel.frame = CGRectMake(padding, describeY, contentSize.width - padding, height + padding);
    }
    
    // 發(fā)出去的消息
    if (outgoing)
    {
        self.titleLabel.textColor = [UIColor whiteColor];
        self.describeLabel.textColor = [UIColor whiteColor];
    }
    else
    {
        self.titleLabel.textColor = [UIColor blackColor];
        self.describeLabel.textColor = [UIColor grayColor];
    }
}

// 根據(jù)寬動(dòng)態(tài)獲取高度
+ (CGFloat)getHeightByWidth:(CGFloat)width title:(NSString *)title font:(UIFont *)font
{
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, width, 0)];
    label.text = title;
    label.font = font;
    label.numberOfLines = 0;
    [label sizeToFit];
    CGFloat height = label.frame.size.height;
    return height;
}

// 設(shè)置元素邊框
-(void)setBorderWithImageView:(UIImageView *) imageView top:(BOOL)top left:(BOOL)left bottom:(BOOL)bottom right:(BOOL)right borderColor:(UIColor *)color borderWidth:(CGFloat)width
{
    // 垂直內(nèi)邊距
    CGFloat verticalPadding = 5.0f;
    if (top)
    {
        CALayer *layer = [CALayer layer];
        layer.frame = CGRectMake(0, -verticalPadding, imageView.frame.size.width, width);
        layer.backgroundColor = color.CGColor;
        [imageView.layer addSublayer:layer];
    }
    if (left)
    {
        CALayer *layer = [CALayer layer];
        layer.frame = CGRectMake(0, 0, width, imageView.frame.size.height);
        layer.backgroundColor = color.CGColor;
        [imageView.layer addSublayer:layer];
    }
    if (bottom)
    {
        CALayer *layer = [CALayer layer];
        layer.frame = CGRectMake(0, imageView.frame.size.height - width + verticalPadding, imageView.frame.size.width, width);
        layer.backgroundColor = color.CGColor;
        [imageView.layer addSublayer:layer];
    }
    if (right)
    {
        CALayer *layer = [CALayer layer];
        layer.frame = CGRectMake(imageView.frame.size.width - width, 0, width, imageView.frame.size.height);
        layer.backgroundColor = color.CGColor;
        [imageView.layer addSublayer:layer];
    }
}

- (void)onTouchUpInside:(id)sender
{
    if ([self.delegate respondsToSelector:@selector(onCatchEvent:)]) {
        NIMKitEvent *event = [[NIMKitEvent alloc] init];
        event.eventName = NIMDemoEventNameLinkingPacket;
        event.messageModel = self.model;
        event.data = self;
        [self.delegate onCatchEvent:event];
    }
}

@end

接下來我們添加圖文按鈕的點(diǎn)擊事件處理蜘腌。

下面代碼添加此處按鈕點(diǎn)擊處理事件

打開文件 NTESSessionViewController.m沫屡， 編輯函數(shù) onTapCell
在 if else if 代碼塊后面添加如下代碼

// 頭部需導(dǎo)入
#import "NTESLinkAttachment.h"
#import "NTESSessionLinkContentView.h"
#import "NTESWebViewController.h"

// ...

// 添加圖文鏈接消息點(diǎn)擊事件
else if ([eventName isEqualToString:NIMDemoEventNameLinkingPacket]) {
   NIMCustomObject *object = event.messageModel.message.messageObject;
   NTESLinkAttachment *attachment = (NTESLinkAttachment *)object.attachment;
   [self onOpenWebView:attachment];
   handled = YES;
}
// ....

// 添加上面調(diào)用的 onOpenWebView 函數(shù) 
- (void)onOpenWebView:(NTESLinkAttachment *)attachment {
    // NTESWebViewController 是點(diǎn)擊顯示的圖文消息后要跳轉(zhuǎn)的頁面，在構(gòu)造函數(shù)添加跳轉(zhuǎn)時(shí)傳入 linkUrl
    NTESWebViewController *vc = [[NTESWebViewController alloc] initWithUrl:attachment.linkUrl];
    // 設(shè)置title
    if (attachment && attachment.title != nil) {
        vc.title = attachment.title;
    }
    [self.navigationController pushViewController:vc animated:YES];
}

//...
#pragma mark - 圖文鏈接
- (void)onTapMediaItemLinkPacket:(NIMMediaItem *)item
{
    // 此處模擬測(cè)試數(shù)據(jù)
    NTESLinkAttachment *attachment = [[NTESLinkAttachment alloc] init];
    [attachment setTitle:@"暖冬季歡樂送"];
    [attachment setLinkUrl:@"http://www.reibang.com/u/bd57ade96e8a"];
    [attachment setImageUrl:@"https://www.baidu.com/img/bd_logo1.png"];
    [attachment setDescribe:@"家具滿1000元減100元再返100元現(xiàn)金券撮珠！點(diǎn)擊查看詳情沮脖！"];
    NIMMessage *message = [NTESSessionMsgConverter msgWithLink:attachment];
    [self sendMessage:message];
}
//...

在目錄 Classes/Sections/Session/ViewController 添加上面使用到的 NTESWebViewController，用來顯示點(diǎn)擊后的網(wǎng)頁
NTESWebViewController.h內(nèi)容如下

#import <UIKit/UIKit.h>

@interface NTESWebViewController : UIViewController<UIWebViewDelegate>
{
    UIWebView *webView;
}

- (instancetype)initWithUrl:(NSString *)url;

@end

NTESWebViewController.m內(nèi)容如下

#import "NTESWebViewController.h"

@interface NTESWebViewController ()<UINavigationControllerDelegate>

@property (nonatomic, strong) UIActivityIndicatorView *activityIndicator;
@property (nonatomic, strong) NSString *url;

@end

@implementation NTESWebViewController

- (instancetype)initWithUrl:(NSString *)url
{
    self = [super init];
    if (self)
    {
        _url = url;
    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // app 尺寸芯急，去掉狀態(tài)欄
    CGRect mainScreen = [UIScreen mainScreen].applicationFrame;
    // 1.創(chuàng)建webview勺届，并設(shè)置大小
    webView = [[UIWebView alloc] initWithFrame:CGRectMake(mainScreen.origin.x, mainScreen.origin.y, mainScreen.size.width, mainScreen.size.height)];
    // 2.創(chuàng)建請(qǐng)求
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:self.url]];
    // 3.加載網(wǎng)頁
    [webView loadRequest:request];
    // 4.將webview添加到界面
    [self.view addSubview:webView];
    [webView setDelegate:self];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)webViewDidStartLoad:(UIWebView *)webView {
    // 創(chuàng)建UIActivityIndicatorView背底半透明View
    CGRect mainScreen = [UIScreen mainScreen].applicationFrame;
    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(mainScreen.origin.x, mainScreen.origin.y, mainScreen.size.width, mainScreen.size.height)];
    [view setTag:108];
    [view setBackgroundColor:[UIColor whiteColor]];
    [self.view addSubview:view];
    
    self.activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 40.0f, 40.0f)];
    [self.activityIndicator setCenter:view.center];
    [self.activityIndicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleGray];
    [view addSubview:self.activityIndicator];
    
    [self.activityIndicator startAnimating];
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    [self.activityIndicator stopAnimating];
    UIView *view = (UIView *)[self.view viewWithTag:108];
    [view removeFromSuperview];
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
    [self.activityIndicator stopAnimating];
    UIView *view = (UIView *)[self.view viewWithTag:108];
    [view removeFromSuperview];
}

@end

4. 添加顯示自定義的圖文消息
   上面第3個(gè)步驟其實(shí)已經(jīng)做了大部分自定義的圖文鏈接消息的顯示工作了，此處添加圖文鏈接消息的轉(zhuǎn)換代碼娶耍，
   編輯NTESSessionMsgConverter.h 頭文件

// ...
@class NTESLinkAttachment

@interface NTESSessionMsgConverter : NSObject
// ...
// 添加鏈接消息
+ (NIMMessage *)msgWithLink:(NTESLinkAttachment *)attachment;
@end

在實(shí)現(xiàn)文件NTESSessionMsgConverter.m 添加以下代碼

//...
#import "NTESLinkAttachment.h"

@implementation NTESSessionMsgConverter
//...
+ (NIMMessage *)msgWithLink:(NTESLinkAttachment *)attachment
{
    NIMMessage *message               = [[NIMMessage alloc] init];
    NIMCustomObject *customObject     = [[NIMCustomObject alloc] init];
    customObject.attachment           = attachment;
    message.messageObject             = customObject;
    message.apnsContent = @"發(fā)來了鏈接信息";
    return message;
}

@end

5.修改消息列表中免姿，顯示的縮略文字

添加顯示[圖文鏈接]字樣，如果不添加榕酒，默認(rèn)顯示的是[未知消息]

編輯 NTESSessionListViewController.m胚膊， 在contentForRecentSession中添加一條邏輯判斷

// ...
#import "NTESLinkAttachment.h"

// ...
- (NSAttributedString *)contentForRecentSession:(NIMRecentSession *)recent{
    //...
    else if ([object.attachment isKindOfClass:[NTESLinkAttachment class]]) {
        text = @"[圖文鏈接]";
     } else {
        text = @"[未知消息]";
     }
    //...
}
// ...

尾篇

到此，云信iOS端的擴(kuò)展自定義消息已經(jīng)完成想鹰。當(dāng)然紊婉，這只是iOS的顯示正常了，其他如web辑舷，Android喻犁，pc等客戶端收到此類的消息，顯示有問題，也是需要擴(kuò)展調(diào)整的肢础。此篇文章其他端的文章我會(huì)陸續(xù)更新还栓，如果有需要的同學(xué)可以關(guān)注下。

以下附上其他版本擴(kuò)展的鏈接

• 網(wǎng)易云信-新增自定義消息（Android版）
• 網(wǎng)易云信-新增自定義消息（Web版）
• 網(wǎng)易云信-新增自定義消息（H5移動(dòng)版）