No Launcher activity found Android Emulator Error

You have to add constructor!

    public static class YourFragment extends Fragment {
    //you have to add constructor!!!!!	
    public YourFragment(){}

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.activity_main, container, false);

            return view;
        }   

    }

SeekBar setOnSeekBarChangeListener Example. Change TextView font size by SeekBar Example.

        TextView mTextView01 = (TextView)findViewById(R.id.textView01);

        SeekBar  mSeekBarTexSize = (SeekBar)findViewById(R.id.seekBarTextSize);
        mSeekBarTexSize.setMax(100);
        mSeekBarTexSize.setProgress(25);

        mSeekBarTexSize.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            public void onProgressChanged(SeekBar seekBar, int progress,
                    boolean fromUser) {
            	mTextView01.setTextSize((float)progress);
            }

            public void onStartTrackingTouch(SeekBar seekBar) {}
            public void onStopTrackingTouch(SeekBar seekBar) {}
        });

[2013-07-06 16:10:29 - SDK Manager] [SDK Manager] Error: Error parsing the sdk.
[2013-07-06 16:10:29 - SDK Manager] [SDK Manager] Error: Failed to create C:\Program Files\android\sdk\add-ons.
[2013-07-06 16:10:29 - SDK Manager] [SDK Manager] Error: Unable to parse SDK content.

You have to create add-ons folder as admin of PC

Warning in AndroidManifest.xml:
tag should specify a target API level (the highest verified version; when running on
later versions, compatibility behaviors may be enabled) with android:targetSdkVersion="?"

Solution:

    <uses-sdk android:minSdkVersion="4"
         android:targetSdkVersion="16" />

GregorianCalendar cal = new GregorianCalendar(); Boolean b = cal.isLeapYear(2012); // true, Android example.

public class MainActivity 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();
        
         GregorianCalendar cal = new GregorianCalendar();
         Boolean b = cal.isLeapYear(2012); // true
         strBuild.append("Is leap year 2012? " + b + "

");
         b = cal.isLeapYear(2014);         // false
         strBuild.append("Is leap year 2014? " + b + "

");
         
         
         txtV.setText(strBuild);
    }
}