iOS 环信消息撤回

这两天在做环信的消息回撤，在网上找了许久没有这种案例，之后官方的一些方法，但是自己做，还是需要花点时间去整理，所以我决定等我把这个做好之后，分享给大家，如果做的不好多多指教，谢谢～  

首先要实现消息撤回就是两个步骤，一个是发送要回撤的透传消息 。一个是接收透传信息，删除要回撤的消息。  

第一步 ： ChatViewController.m 自己定义一个 

1	UIMenuItem *_messageRetracementMenuItem;

 

第二步 

 这个方法里面添加一下撤回字段，我把整段都复制过来了，你们对一下 

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- (void)showMenuViewController:(UIView *)showInView  andIndexPath:(NSIndexPath *)indexPath   messageType:(EMMessageBodyType)messageType {       if (self.menuController == nil) {         self.menuController = [UIMenuController sharedMenuController];     }       if (_deleteMenuItem == nil) {         _deleteMenuItem = [[UIMenuItem alloc] initWithTitle:@"删除" action:@selector(deleteMenuAction:)];     }      if (_copyMenuItem == nil) {        _copyMenuItem = [[UIMenuItem alloc] initWithTitle:@"复制" action:@selector(copyMenuAction:)];     }     if (_transpondMenuItem == nil) {       _transpondMenuItem = [[UIMenuItem alloc] initWithTitle:@"转发" action:@selector(transpondMenuAction:)];    }    if (_messageRetracementMenuItem == nil) {     _messageRetracementMenuItem = [[UIMenuItem alloc] initWithTitle:@"撤回" action:@selector(messageRetracementMenuAction:)];   }       NSString *loginUsername =  [[EMClient sharedClient] currentUsername];    id<imessagemodel> model = [self.dataArray objectAtIndex:self.menuIndexPath.row];   if (messageType == EMMessageBodyTypeText) {      if ([loginUsername isEqualToString:model.message.from]) {          [self.menuController setMenuItems:@[_copyMenuItem, _deleteMenuItem,_transpondMenuItem,_messageRetracementMenuItem]];     } else {         [self.menuController setMenuItems:@[_copyMenuItem, _deleteMenuItem,_transpondMenuItem]];       }      } else if (messageType == EMMessageBodyTypeImage){           if ([loginUsername isEqualToString:model.message.from]) {              [self.menuController setMenuItems:@[_deleteMenuItem,_transpondMenuItem,_messageRetracementMenuItem]];         } else {              [self.menuController setMenuItems:@[_deleteMenuItem,_transpondMenuItem]];         }      } else {          if ([loginUsername isEqualToString:model.message.from]) {              [self.menuController setMenuItems:@[_deleteMenuItem,_messageRetracementMenuItem]];          } else {              [self.menuController setMenuItems:@[_deleteMenuItem]];          }    }     [self.menuController setTargetRect:showInView.frame inView:showInView.superview];      [self.menuController setMenuVisible:YES animated:YES];  }      </imessagemodel>

 

第三步：实现这个回撤的方法 ，我这边做的是在两分钟内撤回，超过两分钟提示

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- (void)messageRetracementMenuAction:(id)sender {       if (self.menuIndexPath && self.menuIndexPath.row > 0) {         id<imessagemodel> model = [self.dataArray objectAtIndex:self.menuIndexPath.row];         NSString *messageId  = model.message.messageId;        // 发送这条消息在服务器的时间戳         NSTimeInterval time1 = (model.message.serverTime) / 1000.0;         // 当前的时间戳          NSTimeInterval nowTime = [[NSDate date] timeIntervalSince1970];          NSTimeInterval cha = nowTime - time1;          NSInteger timecha = cha;          if (timecha <= 120) {          // 开始调用发送消息回撤的方法            [self revokeMessageWithMessageId:messageId conversationId:self.conversation.conversationId];          } else {              [self showHint:@"消息已经超过两分钟 无法撤回"];        }      }  } </imessagemodel>

 

   

//  你撤回之后会发现你消息撤回了，但是还在，但是你要重新运行一下撤回的消息就会没有，所以就是有一步当你撤回的时候，还要手动删除一下。

 主要删除 self.conversation，self.dataArray，self.messsagesSource，这三个，然后刷新一下。

其中  REVOKE_FLAG 和 msgId 一定要和安卓对应，两边要写一样的，要不然另一方撤回这边是接收不到的或者你这边撤回另一方收不到。

还有 message.chatType 也要注意，如果你做的不只单聊，那就要判断一下，我下面代码有些，一个群聊，一个单聊。

 

／／ 发送回撤的透传消息

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- (void)revokeMessageWithMessageId:(NSString *)aMessageId   conversationId:(NSString *)conversationId {       EMCmdMessageBody *body = [[EMCmdMessageBody alloc] initWithAction:@"REVOKE_FLAG"];      NSDictionary *ext = @{@"msgId":aMessageId};      NSString *currentUsername = [EMClient sharedClient].currentUsername;       EMMessage *message = [[EMMessage alloc] initWithConversationID:conversationId from:currentUsername  to:conversationId body:body ext:ext];      if (self.conversation.type == EMConversationTypeGroupChat){           message.chatType = EMChatTypeGroupChat;      } else {           message.chatType = EMChatTypeChat;      }       //发送cmd消息       [[EMClient sharedClient].chatManager asyncSendMessage:message progress:nil completion:^(EMMessage *message, EMError *error) {           if (!error) {             NSLog(@"发送成功");               // 需要自己从dataArray里将聊天消息删掉， 还有self.conversation里，最后刷新             NSMutableIndexSet *indexs = [NSMutableIndexSet indexSetWithIndex:self.menuIndexPath.row];               NSMutableArray *indexPaths = [NSMutableArray arrayWithObjects:self.menuIndexPath, nil];               [self.conversation deleteMessageWithId:aMessageId];               [self.messsagesSource removeObject:message];               if (self.menuIndexPath.row - 1 >= 0) {                   id nextMessage = nil;                   id prevMessage = [self.dataArray objectAtIndex:(self.menuIndexPath.row - 1)];                   if (self.menuIndexPath.row + 1 < [self.dataArray count]) {                       nextMessage = [self.dataArray objectAtIndex:(self.menuIndexPath.row + 1)];                   }                   if ((!nextMessage || [nextMessage isKindOfClass:[NSString class]]) && [prevMessage isKindOfClass:[NSString class]]) {                       [indexs addIndex:self.menuIndexPath.row - 1];                       [indexPaths addObject:[NSIndexPath indexPathForRow:(self.menuIndexPath.row - 1) inSection:0]];                   }               }                [self.dataArray removeObjectsAtIndexes:indexs];               [self.tableView beginUpdates];               [self.tableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade];               [self.tableView endUpdates];               if ([self.dataArray count] == 0) {                   self.messageTimeIntervalTag = -1;               }           }  else {               NSLog(@"发送失败");           }        }];   }

 

 

 第四步：在你接收消息  - (void)didReceiveMessages:(NSArray *)aMessages 这个方法的控制器里 ChatDemoHelper.m  添加接收透传消息的方法，

 接收透传消息是环信系统自带的方法。我这边还有一个没做好，就是别人撤回后在当前聊天界面的刷新没刷新好，你们自己做一下。

 

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1 // 接收透传消息     - (void)didReceiveCmdMessages:(NSArray *)aCmdMessages {      BOOL isRefreshCons = YES;       for (EMMessage *cmdMessage in aCmdMessages) {           EMCmdMessageBody *body = (EMCmdMessageBody *)cmdMessage.body;           if ([body.action isEqualToString:@"REVOKE_FLAG"]) {              NSString *revokeMessageId = cmdMessage.ext[@"msgId"];              BOOL isSuccess = [self removeRevokeMessageWithChatter:cmdMessage.conversationId conversationType:(EMConversationType)cmdMessage.chatType messageId:revokeMessageId];                 if (isSuccess)  {                  if (_chatVC == nil) {                       _chatVC = [self _getCurrentChatView];                }                    BOOL isChatting = NO;                  if (_chatVC)  {                       isChatting = [cmdMessage.conversationId isEqualToString:_chatVC.conversation.conversationId];                 }                   if (_chatVC == nil || !isChatting) {                       [self _handleReceivedAtMessage:cmdMessage];                        if (self.conversationListVC) {                          [[NSNotificationCenter defaultCenter] postNotificationName:@"conversationListRefresh" object:nil];                       }                        if (self.mainVC) {                            [[NSNotificationCenter defaultCenter] postNotificationName:@"conversationListRefresh" object:nil];                            [self.mainVC setupUnreadMessageCount];                        }                       return;                    }                    if (isChatting) {                        isRefreshCons = NO;                  }                   if (isRefreshCons) {                      if (self.conversationListVC) {                          [[NSNotificationCenter defaultCenter] postNotificationName:@"conversationListRefresh" object:nil];                      }                      if (self.contactViewVC) {                         [[NSNotificationCenter defaultCenter] postNotificationName:@"setupUnreadMessageCount" object:nil];                      }                   }                }  else {                 NSLog(@"接收失败");                }            }        }   }

 

 

 

   

 

1 // 删除消息

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- (BOOL)removeRevokeMessageWithChatter:(NSString *)aChatter                       conversationType:(EMConversationType)type                              messageId:(NSString *)messageId{           EMConversation *conversation = [[EMClient sharedClient].chatManager getConversation:aChatter type:type createIfNotExist:YES];   [conversation deleteMessageWithId:messageId];     return YES; }

 

这样就好了，希望能帮到你们～