Google Android has password-protection built in (via Settings, Location & Security, Set up screen lock), and allows you to specify whether you want to enter a PIN or password, or draw a pattern onscreen to gain access. With many of us using our handsets to access our email and other accounts, and increasingly to store sensitive data, we recommend all Android users engage this setting. See also Top ten Android apps.
Of course, we don't expect that everybody will. Android's password-protection is not enabled by default and, even if you do stumble across it, you might decide you'd rather take the risk of what could happen if your handset gets into the wrong hands than deal with the inconvenience of having to enter an access code every time you pick up the phone. For these people, APP Lock offers a compromise, letting them lock down specific applications and otherwise continue using the phone as normal. Visit Best Android apps
On first launch, APP Lock asks you to enter an unlock password. We frequently advise readers to use multiple-digit - and preferably alphanumeric - passwords to protect their data; worryingly, APP Lock will accept a single digit (even Android demands a minimum of four), although there are no greyed-out options that tell wrongdoers how many numbers your passcode contains. The next step is to enter a security question and answer that will be used if you forget your passcode, so security could potentially be ramped up here.
The interface is clean and intuitive, making it easy even for novice users to protect their data. APP Lock lists alphabetically all the applications installed on your phone; simply scroll down and toggle on protection for specific apps where required. You can also use the search field to quickly find an app. Alternatively, you can lock all apps by clicking the relevant option at the bottom of the screen.
If you prefer, you can switch to using a pattern passcode in the Settings menu. Also here is an option to prevent APP Lock demanding your passcode within a certain amount of time of the screen timing out.
The main problem with APP Lock is that by default determined crooks can get around its demands for a security code simply by uninstalling it. Whereas Android sensibly demands that you enter your password before it lets you turn off or change the handset's security code, APP Lock is unable to offer the same security during the uninstallation process without you specifically selecting that option.
You can prevent APP Lock's uninstallation on the System Lock tab. Also here are controls for incoming calls and the installation/uninstallation of other apps, with the latter ideal for antivirus software in the event that mobile malware follows the path of PC viruses that are able to switch off your security safeguards. We’re not sure that this feature would work, but until there are proliferation of mobile viruses it’s impossible to say
Nevertheless, if you're looking for a way to stop 'friends' from swiping your phone and 'fraping' you when you leave your phone unattended, or a nosy partner or parent from keeping tabs on your private messages and photos, APP Lock can be useful. If you've forgotten to prevent APP Lock's uninstallation, you can be safe in the knowledge that these people are highly unlikely to go to the lengths of uninstalling the app just so they can have a quick nose or grab a few laughs.