iOS 自定义富文本消息都是空的

static AVIMMessageMediaType const kAVIMMessageMediaTypeTravelLocation = 80;

@interface AVIMTravelLocationMessage : AVIMTypedMessage

@implementation AVIMTravelLocationMessage

• (void)load {
  [self registerSubclass];
  }

• (instancetype)init {
  if ((self = [super init])) {
  self.mediaType = [[self class] classMediaType];
  }
  return self;
  }

• (AVIMMessageMediaType)classMediaType {
  return kAVIMMessageMediaTypeTravelLocation;
  }

• (void)conversation:(AVIMConversation *)conversation didReceiveTypedMessage:(AVIMTypedMessage *)message {
• (void)receiveMessage:(AVIMTypedMessage *)message conversation:(AVIMConversation *)conversation{
  怎么消息都是空的呢