How to get a list of installed android applications in Android

Starting from the your Activity context you can obtain an instance of PackageManager through the method called  getPackageManager(). Using that class is it possible to get a list of ApplicationInfo objects containing details about apps such as MetaData, Permissions, Services or Activities.

Flag are very import for PackageManager .For example  PackageManager.GET_META_DATA will retrieve only meta data for all packages .

Useful data are for example the name of the app, the packageName used to retrieve additional information with PackageManager methods and the publicSourceDir that represent a simple way to identify system or user applications.
 
** UPDATE: Android Complete tutorial now available here.
 
Method 1:

final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
final List pkgAppsList = context.getPackageManager().queryIntentActivities( mainIntent, 0);

Method 2:

final PackageManager pm = getPackageManager();
//get a list of installed apps.
List packages = pm.getInstalledApplications(PackageManager.GET_META_DATA);

for (ApplicationInfo packageInfo : packages) {
    Log.d(TAG, "Installed package :" + packageInfo.packageName);
    Log.d(TAG, "Launch Activity :" + pm.getLaunchIntentForPackage(packageInfo.packageName));
}

Method 3:Using ResolveInfo

private List getInstalledComponentList()
            throws NameNotFoundException {
        final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        List ril = getPackageManager().queryIntentActivities(mainIntent, 0);
        List componentList = new ArrayList();
        String name = null;

        for (ResolveInfo ri : ril) {
            if (ri.activityInfo != null) {
                Resources res = getPackageManager().getResourcesForApplication(ri.activityInfo.applicationInfo);
                if (ri.activityInfo.labelRes != 0) {
                    name = res.getString(ri.activityInfo.labelRes);
                } else {
                    name = ri.activityInfo.applicationInfo.loadLabel(
                            getPackageManager()).toString();
                }
                componentList.add(name);
            }
        }
        return componentList;
    }