數組排序，時間排序

object1.msgTime是獲取的時間戳

// 時間排序
-(NSArray*)paixuArr:(NSArray *)arr{
    
    NSArray * array=[arr sortedArrayUsingComparator:^NSComparisonResult(id obj1,id obj2) {

                  EMConversationModel *object1 = (EMConversationModel *)obj1;
       
                  EMConversationModel *object2 = (EMConversationModel *)obj2;
                  
                  if ([object1.msgTime doubleValue] < [object2.msgTime doubleValue]) {

                          return NSOrderedDescending;

                  } else if ([object1.msgTime doubleValue] > [object2.msgTime doubleValue]) {

                       return NSOrderedAscending;

                  }

              return NSOrderedSame;

          }];
    return array;
}