Peter Sorotokin

Hi
Thanks Steve
Page 32 : Pro Android 4 : Apress publisher : March 2012

Hi
Is there any certification exam for Android developers from Google or other institutes ???
Thanks

Hi
In the book that I am reading there is a paragraph about teaching the Intent concept :

"" An intent generically defines an intention to do some work. Intents encapsulate several
concepts, so the best approach to understanding them is to see examples of their use.
You can use intents to perform the following tasks:
Broadcast a message.
Start a service.
Launch an activity.
Display a web page or a list of contacts.
Dial a phone number or answer a phone call.
Intents are not always initiated by your application—they’re also used by the system to
notify your application of specific events (such as the arrival of a text message).
Intents can be explicit or implicit. If you simply say that you want to display a URL, the
system decides what component will fulfill the intention. You can also provide specific
information about what should handle the intention. Intents loosely couple the action
and action handler. ""

I completely understand the paragraph except the final portion that I underlined it .
What does that mean ???
Please explain it for me .
What is action and action handler ???
Thanks for your help

Hi
I read in the book that I am reading that for viewing logcat in emulator in Eclipse we could run this command "adb logcat"
But when I type and run this command in cmd of Windows , I receive an error like this " 'adb' is not recognized as an internal or external command,
operable program or batch file. "
What should I do ??? How I can solve this problem ??? Where and how I should enter this command ???

Hi
I have downloaded an offline version of Android API Documentation , But It has not any choice for searching among methods .
How I can do that ??? For example in Java API Doc there is a choice for viewing index of every thing in that ( in alphabetical order )
and in that there were every thing include methods and classes and final constants . But in Android API Doc there is no such thing
and I often need to search among methods . How I can do that easily ???

Hi
In the book that I am reading there is a phrase :

"Even if an application has only one activity and the activity is killed, the
application will still be running in memory"

In this phrase , the underlined word killed , does mean onDestroy() ???
If yes , In several book , I read that when onDestroy() is called by Android , the resourses
that were ocuupied by application will be free ???
I am confuses . Which one is correct ??? The phrase that I mentioned or the things that I read in
several books ???

Hi
In Android development in Eclipse , How I can change between landscape and portrait mode in Android emulator ???
Thanks

Hi
There is a Android source code that I understand it amd know what it does except the role of "this" as a parameter to a method .
The code :
package org.example.audio; import android.app.Activity; import android.media.AudioManager; import android.media.MediaPlayer; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; public class Audio extends Activity implements OnClickListener { private MediaPlayer mp; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); setVolumeControlStream(AudioManager.STREAM_MUSIC); findViewById(R.id.button_1).setOnClickListener(this); findViewById(R.id.button_2).setOnClickListener(this); findViewById(R.id.button_3).setOnClickListener(this); findViewById(R.id.button_4).setOnClickListener(this); findViewById(R.id.button_5).setOnClickListener(this); findViewById(R.id.button_6).setOnClickListener(this); findViewById(R.id.button_7).setOnClickListener(this); findViewById(R.id.button_8).setOnClickListener(this); findViewById(R.id.button_9).setOnClickListener(this); } public void onClick(View v) { int resId; switch (v.getId()) { case R.id.button_1: resId = R.raw.button_1; break; case R.id.button_2: resId = R.raw.button_2; break; case R.id.button_3: resId = R.raw.button_3; break; case R.id.button_4: resId = R.raw.button_4; break; case R.id.button_5: resId = R.raw.button_5; break; case R.id.button_6: resId = R.raw.button_6; break; case R.id.button_7: resId = R.raw.button_7; break; case R.id.button_8: resId = R.raw.button_8; break; case R.id.button_9: resId = R.raw.button_9; break; default: resId = R.raw.button_1; break; } // Release any resources from previous MediaPlayer if (mp != null) { mp.release(); } // Create a new MediaPlayer to play this sound mp = MediaPlayer.create(this, resId); mp.start(); } }

In lines 18 to 26 , what is the role of "this" ??? To which it refers ??? Is it the strange "context" ???
Thanks for your help

Hi
Thanks for your helps.
But what about the part 2 of my question ???
What does line 5 mean ???
Is my receiving true ?? If not please tell me the true one

Hi
I am familiar to standard Java to some extent and no i am learning Android .
In the book that i am reading "Hello Android" , there is a code fragment that i can't understand its meaning
in terms of standard Java Rules . I ask standard Java experts to explain the meaning of this fragment of code
in terms of Java . Thanks

The code fragment :

private void openNewGameDialog() { new AlertDialog.Builder(this) .setTitle(R.string.new_game_title) .setItems(R.array.difficulty, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialoginterface, int i) { startGame(i); } }) .show(); }

I understand this code in this manner , Is this true ??? and if not please tell me the correct one , thanks again

We declare method openNewGameDialog() . And in the first line of its declaration ( line 2 ) we creates an object
of static class Builder that is defined in class AlertDialog . Now my problem begins . I could not understand
remaining code in terms of standard Java . what is .setTitle ( .... ) ??? and again what is .setItems ( ... ) ???
And my second problem is in line 5 . I receive it in this way : a call to OnClickListener constructor and remaining code is
definition of OnClickListener constructor and OnClickListener is a static class that is declared is DialogInterface class .
Is this true ??? thanks again to your help .

Hi
In "Hello Android" book that i am reading , there is a sentence about usefulness of Resources that i can't understand .
Please give me some help about it .
The paragraph is :

"The resource compiler compresses and packs your resources and then
generates a class named R that contains identifiers you use to reference
those resources in your program. This is a little different from standard
Java resources, which are referenced by key strings. Doing it this way
allows Android to make sure all your references are valid and saves
space by not having to store all those resource keys. Eclipse uses a
similar method to store and reference the resources in Eclipse plug-ins."

The underlined sentence has two part .

I understand part one in this way :
When there is some error in for example XML lay out files in Android project in Eclipse IDE ,
The IDE does not work correctly and some red signs are appeared next to files that have
error in left side project browser of Eclipse.

Is the thing that i understood is correct and complete ???

And about part two .
I cant understand it . What it says ??

Thanks for your help

Hi
Between View and ViewGroup which is parent of another ???
Thanks

Hi
I learned Java to some extend and no I am learning Android .
In learning Android , i saw a strange thing that i could not
find its meaning in the java syntax that i learned .
My question is this :

setContentView(R.layout.main);

In this line of code there is a strange thing that i could not understand it .
Firstly i say my question is not about Android and its rules . My question is
about java and its rules and syntax .

What is argument R.layout.main ???

If it was R.layout().main() i could say that this argument says that R class's
method layout() return a class that has a method main () that this main() method
return a value ( primitive or non primitive ) that is argument to method setContentView()

I insist that my question is not about Android . My question is about Java and its syntax .
What does R.layout.main means in java syntax ??

Thanks

Hi
I have writen and run a java application using Eclipse and have run it in command window usind java command
or have run it in Eclipse using right click on project name and choosing Run command . Now I have two question :

How i can produce jar file of my java application in Eclipse in order to run it as an standalone application
in my Windows desktop by double clicking on it ???

How i can produce executable file of my java application other than jar file in Eclipse in order to run my
application by double clicking on it in Windows ???

public class VarArgTest { public static double average ( double... numbers ) { double total = 0.0; for ( double i : numbers ) total += i; return ( total / numbers.length ); } // ends method public static void main ( String [] args ) { double d1 = 10.0; double d2 = 20.0; double d3 = 30.0; double d4 = 40.0; System.out.printf ( "\nd1 = %.1f\nd2 = %.1f\nd3 = %.1f\nd4 = %.1f\n" , d1 , d2 , d3 , d4 ); System.out.printf ( "Average of d1 and d2 is %.1f\n" , average ( d1 , d2 ) ); System.out.printf ( "Average of d1 and d2 and d3 is %.1f\n" , average ( d1 , d2 , d3 ) ); } // ends main } // ends class

So in line 3 if we omit static identifier , the code does not compile . Why ??? Thanks