Translucent status and navigation bar in lock screen for Nexus 4
One of the good aesthetic changes Android 4.4 Kit Kat brought is translucent status and navigation bars. Unfortunately, just like Google Experience Launcher ( GEL ), these are exclusive to Nexus 5.
For the users still rocking the Nexus 4, Floydfire, a Senior Member at XDA, has decompiled, modded and recompiled the framework of Android 4.4 Kit Kat factory images so that you can have status and navigation bars translucent in home screen and lock screen. You will need to install the Google Experience Launcher (click here to download) also if you want translucent bars in home screen.
Download the appropriate recovery flashable zip files based on your Android 4.4 build number. You will need to have unlocked bootloader and custom recovery installed on your device.
Please keep in mind these files only work with the Nexus 4. Download and flash below zip files if you get boot loops.
Source : XDA Developers