Android Studio bug versioncode versionname signed apk issue

Log.e println needs a message error.
E/AndroidRuntime(330): FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{b.paint/b.paint.MainActivity}: java.lang.NullPointerException: println needs a message

Try this code:

		// Error
                String s = null;
		Log.e("bla", s); // !!! error Log.e println needs a message error.
                // OK
		String s = null;
		Log.e("bla", s+""); // OK 

If you often copy your Android project to another you have to using function for obtaining varied information about package.
This code show how get package name in Android application as string:

Context context = getContext(); // this.getContext(); getApplicationContext(); etc.
String sPackName = context.getPackageName();

UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.IllegalArgumentException: already added: Lcz/okhelp/MyMathClass;

First try this solution!!!!!
Select your project in project tree and go to the Eclipse menu Project » Clean » Clean projects selected below » select your project and click OK.

If you create *.apk package with proguard sometimes you must back up the project, delete project, and create new project if you are unable to create *.apk file.

Check your AndroidManifest.xml if all Activity is correctly inserted. If you add a library project to Main project you have to insert Activity from library to Main project AndroidManifest.xml


Problem with the library.
I deleted library project from project tree and again put the _library project into the main project. This problem was resolved.
1.)Go to Project » Properties » Java Build Path » Libraries and remove (your projects) click OK.
2.)Go to Project » Clean » Clean projects selected below » select your project and click OK.
3.)Add again your LIBRARY project to your MAIN project Project » Properties » Java Build Path » Libraries.
See image below.

Problem with a *.apk file
If you create signed *.apk, you have to delete previous *.apk from your PC folder.

Context context = getApplicationContext();
Drawable drawable = context.getResources().getDrawable(R.drawable.my_image);
// convert drawable to bitmap
Bitmap bitmap = ((BitmapDrawable)drawable).getBitmap();
// convert bitmap to drawable
Drawable d = new BitmapDrawable(bitmap);

Android example source code.

Brand	Samsung
Model (codename)	Galaxy Y (S5360)
Cena, včetně DPH	2400 / 06.2012
Display size (v palcích)	3
Display-resolution	240x320
Dotek-typ	kapacitní
CPU typ	BCM21553
CPU MHz	832
CPU core
L2 cache	?
RAM	256
ROM	512
GPU	VideoCore IV
NenaMark2 Benchmark	12
GPU-GLBenchmark
Baterie mAh	1200
Foto MPx	2
Autofocus	ne
Video
Official Android ICS	Android OS v 2.3
CyanogenMod support
Dotek-prstů-max
Display-ppi	133
Display-retina	41%
Network	čîtyřpásmový GSM 850/900/1800/1900 MHz , HSDPA 2100 MHz
Connectivity	Bluetooth v2.0 plus EDR plus support A2DP, USB host
Pozn.	CPU ARMv6, GPU 20MT/s OpenGL ES 2.0