1.Tweak.xm

%new
- (void)clickLeftItem:(UIButton *)button {
  [UIAlertView showWithTitle:@"clear"
                       message:@"are you sure to clear chat list?"
             cancelButtonTitle:@"OK"
             otherButtonTitles:@[@"CANCEL"]
                      tapBlock:^(UIAlertView *alertView, NSInteger buttonIndex) {
      if (buttonIndex == [alertView cancelButtonIndex]) {
          NSLog(@"ok");
          UIViewController *viewController = [objc_getClass("SettingGeneralViewController") new];
          objc_msgSend(viewController,NSSelectorFromString(@"clearLocalData"));
      } else if ([[alertView buttonTitleAtIndex:buttonIndex] isEqualToString:@"CANCEL"]) {
          NSLog(@"cancel");
      }
  }];
}

%end

if want to know how to add left bar button ,please check the before blog.

2.effect

clear chat history

after click ok button, the chat history will be cleared.

3. Postscript

any problem can comment below, I will response you.