Develop Reference

Alternative for missing app bar in Android TV

I just notice that my Android app, when I run it on
Android TV with leanback intent, that it doesn't
show a sandwich button for the menu items.
This is missing, and everthing else like the title:
What is the suggested alternative? Is it possible
to listen to a button on the remote control and
make the menu items visible?

Incase you are looking for tab based navigation, The Leanback templates provide side navigation in the browse experience, which works well for many apps. If you need tab navigation (typically displayed horizontally across the top of the app), you can instead use Leanback Tabs.
Add the library to your project:
implementation "androidx.leanback:leanback-tab:$version"
Sample code
val leanbackTabLayout = findViewById<LeanbackTabLayout>(R.id.tab_layout)
val leanbackViewPager = findViewById<LeanbackViewPager>(R.id.view_pager)
leanbackViewPager.setAdapter(adapter)
leanbackTabLayout.setupWithViewPager(leanbackViewPager)
Then implement tabs using LeanbackTabLayout and LeanbackViewPager by following the existing ViewPager guide. Note that LeanbackViewPager is based on ViewPager, not ViewPager2.
Note that only themes that are derived from Theme.AppCompat are supported.

Android 4.2 : Main Activity actionbar hides launching the new activity

I am developing an android application, where in MainActivity i am creating the actionbar with tabs for the application. i do have set listener for Tab click of actionbar which launches new activity in the application...till this everything is working fine.
Problem is : When new activity get created on Tab click, ActionBar of the application (which is created in main activity) is not shown....it shows application icon and name but NO TABS which i created in Main Activity.
I am no using any supported libraries to support previous versions of android. I am using Android 4.2.
Thanks in advance.

A solution can be to extend the onCreateOptionMenu method as shown here.
This provides somewhat guidance on a possible solution, using fragments instead of activities.

I think the first answer to this question might help you:
Android - Switch Tabs from within an Activity within a tab
Particularly the links to the example source code

Android Gui with Fragment

I was just curious if anyone could link me with some help or show me some code that would show a tab view with scrollable content like the pulse app both horizontal and vertical scroll content. I have it working entirely using TabActivity and Activity classes but I am have a really hard time converting it to either using fragments and or ActionBarTab setups since TabActivity has since been depreciated. It has been bothering me and I have been reading the API but I was just curious if there were any simple examples to where I could see how to set that up using FragmentActivity and Tab Manager or the ActionBar.
Thank you in advance.

You can use ActionBarSherlock. It is very neat and back-compatible.

Converting Existing App to use Tabs

I have an existing app that is using a Dashboard style pattern where there's a main menu, and clicking icons on the main menu drive start different activities... In order to navigate to a different function, you need to go back to the Dashboard menu and select another icon.
I want to change my application to a tabbed format similar to the one below with Icons:
What type of View is being used below? Is this a FragmentActivity? Also, what is the best approach to go about conversion? I have a bunch of layouts with listviews in linear/relative layouts... Will I be able to reuse any existing code? I want also to be able to use the solution with Android 2.1 and up if possible.
Thanks!

In the image you provided, it looks to be a TabHost that is used (which can be within a normal Activity or a Fragment Activity) and will be available for Android 2.1 and beyond when using the Android Support library. Based upon your description, you most likely have an Activity per each of your items that you will probably want to convert into a different Fragment. This may take a little time, but a Fragment is very similar to a normal activity in many ways, so once you start getting used to it, converting over the old Activities should be a breeze.
If you plan on using these tabs and you follow the Android design UI guidelines, you may want to use the TabHost in conjunction with a ViewPager. There is a great tutorial for this online that also allows for backward compatibility (down to at least 2.1) found here: http://thepseudocoder.wordpress.com/2011/10/13/android-tabs-viewpager-swipe-able-tabs-ftw/
Support library for fragments/viewpager: http://developer.android.com/tools/extras/support-library.html
More info about a TabHost and using Tabs with fragments can be found here:
http://developer.android.com/reference/android/widget/TabHost.html
http://thepseudocoder.wordpress.com/2011/10/04/android-tabs-the-fragment-way/

You can use TabLayout and a TabActivity to achieve layout in picture. Bad news is these are deprecated as of Android 3.0. Google advises to use fragments instead of these.

How to show activities inside of a running activity?

I want to show my activities inside of a running activity. I need something like frame in html language that is used for showing other pages inside a page. I know Tabhost has this ability. Which one of other controls has this ability?
Thanks,

Google introduced fragments in Android 3.0 and upper to create a portion of user interface in an Activity. But it is not two Activity, becuase activity <> window. For lower version you can manually load xml layout in your activity.

The Fragment API is really your best choice, it's quite easy to use and you can dynamicly add them to your Activity Layout (take a look to Framgent For All - google Article) by code using the FragmentManager, this feature it's since 3.0 altough Google also released a pretty nice Compatibility Package that you can download out of the SDK Manager and added to your project like this Fragment For All: