Code Snippet - Installed/Running Applications List

Create an Android Project as mentioned here.

List of Installed Apps:
Add the below code to get all the installed apps,

PackageManager packageManager = getPackageManager();

List<ApplicationInfo> appList =                  packageManager.getInstalledApplications(PackageManager.GET_ACTIVITIES);

for(ApplicationInfo info : appList){

    Log.i("AppInstallChecker",info.loadLabel(packageManager).toString());

 }

List of Running Apps:

Use the below code to get the list of running apps,

ActivityManager actvityManager = (ActivityManager) 

                                                                 this.getSystemService( ACTIVITY_SERVICE );

List<RunningAppProcessInfo> procInfos = actvityManager.getRunningAppProcesses();

for(RunningAppProcessInfo info : procInfos){

        Log.i("Running",info.processName);

 }

Check for App installed or not :

protected boolean isAppInstalled(String packageName) {

        Intent mIntent = getPackageManager().getLaunchIntentForPackage(packageName);

        if (mIntent != null) {

            return true;

        }

        else {

            return false;

        }

    }

Courtesy : 
http://stackoverflow.com/questions/13566479/check-app-is-installed-on-device-android-code
http://www.dreamincode.net/forums/topic/138412-android-20-list-of-running-applications/