Ajouter deux packages dans un même projet

Je ne sais pas pourquoi tu veux avoir R.java pour chaque package

Pour Créer sous-package.
the R.java a été crée automatiquament.

Google Developper
Code:

1 2 You should never edit this file by hand
and.mainpackage
and.mainpackage.sousmain1
and.mainpackage.sousmain2
and.mainpackage.sousmain3

....

http://developer.android.com/resourc...llo-world.html

Citation:

R class

In Eclipse, open the file named R.java (in the gen/ [Generated Java Files] folder). It should look something like this:

package com.example.helloandroid;

public final class R {
public static final class attr {
}
public static final class drawable {
public static final int icon=0x7f020000;
}
public static final class id {
public static final int textview=0x7f050000;
}
public static final class layout {
public static final int main=0x7f030000;
}
public static final class string {
public static final int app_name=0x7f040001;
public static final int hello=0x7f040000;
}
}

A project's R.java file is an index into all the resources defined in the file. You use this class in your source code as a sort of short-hand way to refer to resources you've included in your project. This is particularly powerful with the code-completion features of IDEs like Eclipse because it lets you quickly and interactively locate the specific reference you're looking for.

It's possible yours looks slighly different than this (perhaps the hexadecimal values are different). For now, notice the inner class named "layout", and its member field "main". The Eclipse plugin noticed the XML layout file named main.xml and generated a class for it here. As you add other resources to your project (such as strings in the res/values/string.xml file or drawables inside the res/drawable/ direcory) you'll see R.java change to keep up.

When not using Eclipse, this class file will be generated for you at build time (with the Ant tool).

You should never edit this file by hand.