Emulator window was out of view and was recentred
Emulator] WARNING: Data partition already in use. Changes will not persist!
Emulator] WARNING: SD Card image already in use: C:\Documents and Settings\user_name\.android\avd\hvga21_up1_7.avd/sdcard.img
Emulator] WARNING: Cache partition already in use. Changes will not persist!

Basic step
Try restart Eclipse if using from menu File->Restart

Other solutions

Solution 1: try restart ADB server
//android.okhelp.cz/how-quickly-restart-adb-exe-adb-server-android-emulator-example/


Solution 2:

Delete Run Configuration

//android.okhelp.cz/android-emulator-wont-run-application-started-from-eclipse/





Solution 3:
Try delete:

c:\Documents and Settings\user_name\.android\avd\my_avd.avd\cache.img
c:\Documents and Settings\user_name\.android\avd\my_avd.avd\userdata-qemu.img

Try solution 4:
Eclipse menu select Window->Preferences->Android

Windows 32

FROM: C:\Program Files\Android\android-sdk
TO: C:\PROGRA~1\Android\android-sdk

Windows 64

FROM: C:\Program Files (x86)\Android\android-sdk
TO: C:\PROGRA~2\Android\android-sdk

Calendar dateOfYourBirth = new GregorianCalendar(1998, Calendar.SEPTEMBER, 17); Calendar today = Calendar.getInstance(); Android example.

public class HoriziontalScrollActivity extends Activity {
	TextView txtV;
	Context cntx;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        txtV = (TextView)findViewById(R.id.idLabel);
        cntx = this;
        StringBuilder strBuild = new StringBuilder();

        // enter your date of birth
        Calendar dateOfYourBirth = new GregorianCalendar(1998, Calendar.SEPTEMBER, 17);
        Calendar today = Calendar.getInstance();
        int yourAge = today.get(Calendar.YEAR) - dateOfYourBirth.get(Calendar.YEAR);
        dateOfYourBirth.add(Calendar.YEAR, yourAge);
        if (today.before(dateOfYourBirth)) {
            yourAge--;
        }  
        strBuild.append("You are " + yourAge + " old!");
         txtV.setText(strBuild);
    }
}

Brand	Samsung
Model (codename)	i9250 Galaxy Nexus
Cena, včetně DPH	9000
Veikost Displaye v palcích	4.65
Display-resolution	1280x720
Dotek-typ	kapacitní
CPU typ
CPU MHz	1200
CPU core	2
L2 cache
RAM	1 GB
ROM	16 - 32 GB
GPU	TI OMAP 4460 1,2 GHz dual-core
NenaMark2 Benchmark
GPU-GLBenchmark
Baterie mAh	1750
Foto MPx	5
Autofocus	yes
Video	480p - 30 frames/s
Official Android ICS	Android 4.0 Ice Cream Sandwich
CyanogenMod support
Dotek-prstů-max
Display-ppi
Display-retina
Network	GSM&EDGE: 850 / 900 / 1.800 / 1.900
Connectivity
Pozn.

samsung-i9250-galaxy-nexus image

The source attachment does not contain the source for the file TextWatcher.class.
You can change the source attachment by clicking Change Attached Source below:

You have to add JDK src.zip path to dialog as on image below.
[caption id="attachment_1091" align="alignleft" width="282" caption="class file editor source not found Eclipse warning"][/caption]

Or go to Project > Properties > Java Build Path > Libraries
Expand JRE System Library. Expand rt.jar.
Select Source attachment and double click or Edit.
Type path the source code file (External File…) and press OK.

[caption id="attachment_1094" align="alignleft" width="300" caption="Java project build path"][/caption]

Or type path in Java JRE definition

[caption id="attachment_1105" align="alignleft" width="300" caption="Java JRE deifiniton path in Eclipse"][/caption]

How open String.class or others keywords definition with Eclipse.

Now if mouse move about keywords String or F3 on keywords and press button in yellow field will opened String.class

public class MainActivity extends Activity {
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}
		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();
			
			canvas.drawColor(Color.GREEN);
            
            Bitmap b = Bitmap.createBitmap(200, 200, Bitmap.Config.ALPHA_8);
             paint.setColor(Color.BLUE);
            
           Canvas c = new Canvas(b);
           c.drawRect(0, 0, 200, 200, paint);
           
           canvas.drawBitmap(b, 10,10, paint);
		}

	}
}