What do .apk files do?

[Brew Swayne]

.apk files

I use AirDroid for the majority of my phone management (moving docs/media/photos from phone to Mac and vice versa) and I just noticed that I have the option to download the .apk of all my apps to my computer. What exactly does this do? I don't expect it to make the app usable on my desktop, but does it basically put the app on my computer so that I could install it to another android device?

 

[SpookDroid]

Yup, that's basically what it is. It copies the app's main installation file and transfers it to your computer (or other devices) so that you can manually install them (aka Sideloading) in the same device later or in a different device. Note that not all apps can do this (some might need root for you to copy the file) and some others will check a device-tied license for them to work, so even if you install them in another device, if the ID doesn't match or the license is not present, the app won't run. You might also run into trouble with incompatible devies/OS versions,etc.

 

[zhris]

The .apk (or Android Package) file is the app itself, kinda like an .exe file on Windows. When you download an app from the store, what's happening in the background is that the .apk file is downloaded and installed to your phone. This can be done manually (often called sideloading), often used for apps that arent in the store, rooted/flashed phones that don't have the store installed, or for installing pirated apps.

 

[Brew Swayne]

Ok, sounds like I was on the right track. I'm thinking this might be useful for me, but I'd like a 2nd (or 3rd or 4th) opinion...

I've downloaded A LOT of apps over time, but there are quite a few that I don't need or go to on a regular basis. A currency converter, for example, is something I don't need on my phone when I'm not traveling outside the country, Since the Play Store doesn't have any sorting/grouping options that I'm aware of, I've got to scroll through my entire apps list to find the one I want to re-install on my phone....which is a total pita since Play sorts them chronologically based on install date. So if I'm looking for an app that I used a year ago, I could be scrolling for quite a while until I find it. But if I have the .apk files of all of my apps, I can just add a tag to each file. Seems like that would make it a faster process to find a specific app that I want to reinstall on my phone at a later date. That should work, right? What are other reasons for downloading the .apk file?

 

[zhris]

Ok, sounds like I was on the right track. I'm thinking this might be useful for me, but I'd like a 2nd (or 3rd or 4th) opinion...

I've downloaded A LOT of apps over time, but there are quite a few that I don't need or go to on a regular basis. A currency converter, for example, is something I don't need on my phone when I'm not traveling outside the country, Since the Play Store doesn't have any sorting/grouping options that I'm aware of, I've got to scroll through my entire apps list to find the one I want to re-install on my phone....which is a total pita since Play sorts them chronologically based on install date. So if I'm looking for an app that I used a year ago, I could be scrolling for quite a while until I find it. But if I have the .apk files of all of my apps, I can just add a tag to each file. Seems like that would make it a faster process to find a specific app that I want to reinstall on my phone at a later date. That should work, right? What are other reasons for downloading the .apk file?

One thing to jeep in mind with that is that if you download and store an APK, you may be a few versions behind when you re-install it. I used to run into that problem myself, but now once a month or so I go through the My Apps section of the Play Store, and remove what I don't use or plan to keep. Now I'm down to about a dozen or so apps that I re-install every time I flash or reset my phone.

 

[Brew Swayne]

Once I re-install an out of date app on my phone, I should be prompted to update it as soon as I try to launch it, right?

 

[SpookDroid]

In theory, yes. But if the app ID has changed for some reason (either from the app that's copying the APK or if the dev changed the name or something or you just installed it in a phone that uses a different package/version), it won't match the Play Store and it won't prompt for update.

 

[Brew Swayne]

Cool. Thanks for the info everyone.

 

[SpookDroid]

Actually now you got me thinking... not even sure the Play Store will 'see' sideloaded apps! I usually sideload an older version of Samsung's SmartView because they stripped the ability to mirror the TV to a phone or tablet from their newer version (and they never kept the compatibility list up to date, anyway), and even though there was a newer SmartView app in the Play Store, my tablet and phone never prompt me to update.

 

[Brew Swayne]

Ok, now you got me thinking (which is never good) and I want to make sure I've got the gist on how all this works....or should work. So I download an .apk to my computer. Let's say it's ESPN and the filename is espn.apk. Then I uninstall the ESPN app from my phone. Fast forward 1 year and I decide I want ESPN on my phone again, so I side load it using the espn.apk file. This will install the exact same version of the ESPN app that I had on my phone 12mo prior, correct? At this point, I may or may not be prompted to update the app to the most current version, possibly depending on whether or not the dev changed the file name (maybe the new name is espnownedbydisney.apk). If I'm not prompted to update, will the app continue to function the same as it did when it was the most current version?

I think I'm starting to see a little more upside to this sideloading thing now other than just being able to have an easily sortable catalog of all of my apps. Just as you prefer an older version of SmartView, there are definitely apps I use regularly that I may have really preferred an older version of. If this is the case, then I'm gonna guess that there's sites out there that would have the .apk file for practically every version of every* app that's out there.

*unless the dev requires the most current version of the app

Am I still tracking or did I veer way off course here?

 

[SpookDroid]

Nope, you got it. And like you said, it's up to each dev to grant access or deny it to older versions. For instance, I know for sure that Whatsapp will only allow certain recent versions to work, and all other older ones will display a message stating that unless you update (which would redirect you to the play store to download) the app won't work. Most bank apps are the same and won't even load anything unless they're in the latest versions, but that's the app detecting it's an older version, not the system.

And yes, there are those sites. It's a grey area whether the free apps' apks are legal or not, but they're there. Just the usual warning: beware of where you obtain them. Unless you trust the source, there's always a chance that the apk might have 'something else' injected into the code.

 

[Brew Swayne]

Learning has occurred. Thanks.