BuddyPress.org

If you want to redirect all users(admin,subscriber,all roles) to homepage after login, just use this line at your theme functions.php file
add_filter( 'login_redirect', create_function( '$url,$query,$user', 'return home_url();' ), 30, 3 );

Or if you filter a bit, like Admin users will redirected to dashboard, and all others to home page, you can place this code instead of that

function wp_bp_custom_login_redirect( $redirect_to, $request, $user ) {
	global $user;
	if ( isset( $user->roles ) && is_array( $user->roles ) ) {
		if ( in_array( 'administrator', $user->roles ) ) {
			return $redirect_to;
		} else {
			return home_url();
		}
	} else {
		return $redirect_to;
	}
}

add_filter( 'login_redirect', 'wp_bp_custom_login_redirect', 30, 3 );

It doesn’t work like that. In a multisite instance, your users can all have their own blogs (think wordpress.com). What BuddyPress does is allow you to see all of the activity from those subsites in one Activity feed (among other things).

I have set up the categories in the main site, and I expected to see the same categories on every site, but it doesn’t work.

Although this isn’t a BP feature, there is a plugin that does this. It hasn’t been updated in a while, but you could test it out, or purchase support from Brajesh and request a fix if you run into issues:
http://buddydev.com/plugins/mu-global-terms/. There’s a write-up on the plugin here: http://wptavern.com/wordpress-multisite-global-terms-plugin-share-taxonomies-across-a-network

Also in the user activity stream I cannot see the posts the user has written in his own blog.

That SHOULD work. You mention a custom post type though: is that the activity you are hoping to see? By default BP only shows posts and comments, not custom post types. You can register custom post types: https://codex.buddypress.org/plugindev/post-types-activities/

If the subsite that you are hoping registers activity is set to discourage search engines in Settings/Reading then it won’t register on the main site.

You may also want to try one of the default themes (twentyxx) to see if it’s your theme screwing things up. Many themes that tout themselves as BuddyPress-Ready, are doing some funky things best left to plugins in their functions.php file.

I’ve recently installed Buddypress to my WP theme

Can you explain exactly the steps you took?

Have you tried raising this with your theme’s creators, this seems more like a theme problem than a BuddyPress issue.

Which theme is that? BuddyPress doesn’t ask for 2 usernames. The WordPress username and the BuddyPress username are one and the same. It looks as though your theme is asking for it twice

If you want to redirect all users(admin,subscriber,all roles) to homepage after login, just use this line at your theme functions.php file

add_filter( 'login_redirect', create_function( '$url,$query,$user', 'return home_url();' ), 30, 3 );

Or if you filter a bit, like Admin users will redirected to dashboard, and all others to home page, you can place this code instead of that

function wp_bp_custom_login_redirect( $redirect_to, $request, $user ) {
	global $user;
	if ( isset( $user->roles ) && is_array( $user->roles ) ) {
		if ( in_array( 'administrator', $user->roles ) ) {
			return $redirect_to;
		} else {
			return home_url();
		}
	} else {
		return $redirect_to;
	}
}

add_filter( 'login_redirect', 'wp_bp_custom_login_redirect', 30, 3 );

Frankly saying, This is something concern of theme, not plugin, as plugin developer won’t know theme structure and styling users are using, unless they use BuddPress default template parts. I did that thing actually in one of my other plugin, BuddyPress User Account Type, It wasn’t good as I said, Its theme dependent.

But It is a nice feature to have actually, I am considering to develop a separate plugin soon for this feature, tho I need to see the feasibility first.

Sorry @life5000, I noticed that earlier in this post I mentioned you should add the snippet to your theme’s functions.php. That’s not right. It should go into your theme’s (or child theme’s) style.css file.

I’ve just updated it so it has the right info.

My opinion: For simplicity, Let the user figure out that he/she needs a child theme. Period.

@venutius Good advice yeah. From WP admin – plugins > add new, search for ‘child theme creator’. Plenty of options that will do the job.

I’ve not tested it myself but there are plugins such as “One Click Childtheme” available, maybe for newbies we should be recommending that?

Themes which make use of option panels may allow you to only use the parent theme. If you can cover the changes you need by using that panel. But if you need make custom changes to css or add additional functionality, save yourself potentially big headaches and use a child theme. They don’t exist for fun.

The ‘active’ theme should always be the child theme. That’s not my opinion, that’s fact. And you don’t need to be a developer to use, or create one. Most premium themes are packaged with a child theme, and if you don’t have one, just add a plugin and create one. Then activate it. You will find no WordPress developer that doesn’t recommend the use of a child theme.

Maybe this will help – https://www.elegantthemes.com/blog/resources/wordpress-child-theme-tutorial

By the way @henrywright is one of the BuddyPress Core developers who joined team recently but look at where he said that the code should be put. He actually meant “style.css” not “function.php”. What do you say about this @style960? Even the core developer himself is not recommending the child theme!

I know @style960. Look, probably not all members are using default themes such 2015 which get updated every now and then OK? Some themes will never get updated anyway. Some people just want to get the work done as soon as possible and once they realize that they are loosing the changes with updates then they can find a solution to that. What’s the use of giving these people lengthy tutorials that are going to get them frustrated and they quit half way? They should start small then improve on that. If you’re a programmer at all, you first started by writing a very simple program that says “Hello World!” not a super complicated program. This is what I’m doing here!

@william_oneb Please stop giving members advice to edit their active theme. All changes of this nature should always be made in a child theme. Check the codex – https://codex.wordpress.org/Child_Themes

@bennyhoang

Paste this code in your theme’s functions.php

function bennyhoang ($atts) {
         // Start by checking if the user if logged in
          if ( is_user_logged_in() ) {
         // Let's grab the user id
         $user_id = bp_loggedin_user_id();
         // Let's find a field called name. (REPLACE "NAME" WITH THE NAME OF THE FIELD YOU WANT)
         $Name = xprofile_get_field_data( 'Name' ,$user_id);
         // Let's output that field
         return $Name;
   } 
}

add_shortcode( 'benny', 'bennyhoang' ); 

[benny] is your shortcode! Use it your pages/posts!

@life5000, Please find a file called style.css in your active theme, put this code there, save the file and reupload that file. Of course 300% is way too large but hey, I want you to see that your changes are actually working. Please adjust that size accordingly e.g 140%

#activity-stream p {
    font-size: 300%;
}

Scenario 1 is easy:

Create a template overload of this file:
\buddypress\bp-templates\bp-legacy\buddypress\members\single\profile\profile-loop.php

Use bp_get_the_profile_field_name() to determine of the current user should be able to see the field – based on the current member’s PMP level.

That is incorrect. Always use a child theme for such changes, whether in style or amended/additional functionality.

The advice above will mean css changes you have made will be lost when your theme is updated. Make all edits in a child theme, every time.

You don’t really need a child theme. You can just “inspect element” with your web browser and find the class or element you want to modify with CSS. Once you find it, go to your active theme’s style.css and write new code to change the appearance.

If I’m not wrong, you need the child theme if you just want to modify the registration form layout or template. Hope that points you in the right direction.