PackageManager

Retrieve application version

public String getAppVersion() throws PackageManager.NameNotFoundException {
    PackageManager manager = getApplicationContext().getPackageManager();
    PackageInfo info = manager.getPackageInfo(
                            getApplicationContext().getPackageName(), 
                            0);

    return info.versionName;
}

Version name and version code

To get versionName and versionCode of current build of your application you should query Android's package manager.

try {
    // Reference to Android's package manager
    PackageManager packageManager = this.getPackageManager();

    // Getting package info of this application
    PackageInfo info = packageManager.getPackageInfo(this.getPackageName(), 0);

    // Version code
    info.versionCode

    // Version name
    info.versionName

} catch (NameNotFoundException e) {
    // Handle the exception
}

Install time and update time

To get the time at which your app was installed or updated, you should query Android's package manager.

try {
    // Reference to Android's package manager
    PackageManager packageManager = this.getPackageManager();

    // Getting package info of this application
    PackageInfo info = packageManager.getPackageInfo(this.getPackageName(), 0);

    // Install time. Units are as per currentTimeMillis().
    info.firstInstallTime

    // Last update time. Units are as per currentTimeMillis().
    info.lastUpdateTime

} catch (NameNotFoundException e) {
    // Handle the exception
}

Utility method using PackageManager

Here we can find some useful method using PackageManager,

Below method will help to get the app name using package name

private String getAppNameFromPackage(String packageName, Context context) {
    Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
    mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
    List<ResolveInfo> pkgAppsList = context.getPackageManager()
            .queryIntentActivities(mainIntent, 0);
    for (ResolveInfo app : pkgAppsList) {
        if (app.activityInfo.packageName.equals(packageName)) {
            return app.activityInfo.loadLabel(context.getPackageManager()).toString();
        }
    }
    return null;
}

Below method will help to get the app icon using package name,

private Drawable getAppIcon(String packageName, Context context) {
    Drawable appIcon = null;
    try {
        appIcon = context.getPackageManager().getApplicationIcon(packageName);
    } catch (PackageManager.NameNotFoundException e) {
    }

    return appIcon;
}

Below method will help to get the list of installed application.

public static List<ApplicationInfo> getLaunchIntent(PackageManager packageManager) {

    List<ApplicationInfo> list = packageManager.getInstalledApplications(PackageManager.GET_META_DATA);

    return list;
}

Note: above method will give the launcher application too.

Below method will help to hide the app icon from the launcher.

public static void hideLockerApp(Context context, boolean hide) {
    ComponentName componentName = new ComponentName(context.getApplicationContext(),
            SplashActivity.class);

    int setting = hide ? PackageManager.COMPONENT_ENABLED_STATE_DISABLED
            : PackageManager.COMPONENT_ENABLED_STATE_ENABLED;

    int current = context.getPackageManager().getComponentEnabledSetting(componentName);

    if (current != setting) {
        context.getPackageManager().setComponentEnabledSetting(componentName, setting,
                PackageManager.DONT_KILL_APP);
    }
}

Note: After switch off the device and switch on this icon will come back in the launcher.