Develop Reference

Making Menu programmatically in android

I am trying to make menu from the code. I want to know what is the programmatic equivalent of android:showAsAction. I know we can have it in XML.

Call setShowAsActionFlags with one of the constants you want.
See constants section for constants you can pass.

How to implement an interface like this in Android application?

good afternoon
How could I get a design like this in my android application?
http://s2.subirimagenes.com/otros/previo/thump_7851660img20120718wa0000.jpg
That is, divided into three areas with different background color to the background activity. And for example in the first zone instead of having these options has a TextView and edit text where you enter something.
How to make something like that image what kind of layout is more recomedable use? Linear, Relative ...
Thanks in advance

You could use a fragment layout and use fragments to get that layout

The best way is to use PreferenceScreen with three PreferenceSections.

Android: programmatically change the application label?

It doesn't seem possible, but I was hoping someone may be aware of a way. Can the label of the application (the one defined in the manifest file by android:label="#string/app_name") be set from code?

That is read-only, AFAIK.
If your objective is to change the title bar of your activities, you can call setTitle().

I mostly use this to change actionBar's text pragmatically in onCreate() method....very easy!
getSupportActionBar().setTitle("yourString");

I used:
this.setTitle("YourString");

Convert layout to class

I currently have a layout that has scrollviewer as main layout, and a relative one (with a lot of views) as my app layout, but now I need to make tabs, the android tutorial instructs to make the actual layout of each tab programatically, how do I convert my current layout (xml) to a class? Is there any guideline to follow? how do I set the relative layout inside the scrollviewer and how do I specify the "android:layout_below="SOMETHING"" and all that properties?

I din't understand your question very well but, when creating the TabLayout programaticaly you define the activities that are used for each of the tabs. Each of them should have setContentView( 'activity layout')

In order to access XML elements in Android you need to do something like the following:
Button submitButton = (Button) myActivity.getViewById(R.id.btnSubmit);
Then you can call things like submitButton.setVisibility(View.HIDDEN) to hide it, or whatever else you need to do with it.
This should work for any layout elements.
Make sure you do this in your onActivityStart method, or else you will throw runtime exceptions.
There isn't any way to automatically "convert" an XML layout file to a class, unless you're using an XML parsing algorithm of some sort, which sounds like way more than you're trying to do.
Hope this helped!

Applying a custom title bar for the entire application

I actually want to apply a custom title bar (kind of like the Action Bar), but since i'm developing for Froyo, I actually need to have it in a xml file. The trivial way to do this is to just write the code to create the title bar in each of the activities.
I did search around for some efficient ways and found this on SO
Similar Problem
There are 2 solutions proposed over there, but I am having problems in implementing them.
To include the layout of your title bar in the layout of all the Activities. My question is say I have a sample layout as follows, where should the include tag go and do I need to use Theme.NoTitleBar theme for the application in order to get it working?
To subclass Activity and then derive all of my Activities from that. Should the custom Title bar creation method be defined in the onCreate method of the subclassed Activity. Because if I do this, the custom title bar does appear, but it appears blank. No buttons,etc.. are present on it.
Thanks in advance for any help you provide

The tag belongs inside the top level view container (linear layout/relative layout). Yes use NoTitleBar so you don't have the Android provided title bar in your app window.
There is obviously an issue with your code there, with out any code in your post I cannot help you.