Even an uninformed Android user might have heard of APK files. APK or Android application packages are files that are installed as mobile applications on Android devices. Every app you see on your Android device comes from an APK file.
This is not a misunderstanding of APK files. However, there is more about APK files that people in the mobile app market should know.
What is an APK file?
One way to define APK files is to refer to them as a packaged version of an app that can only be opened on the Android operating system. This is a good way to understand the basic concept of APK files. More precisely, APKs are a file format used to install and distribute mobile applications.
Both Android application packages and Android package kits are accepted as APK.
Until 2018, the Google Play Store installed apps as APKs on Android devices. In 2018, it changed to AABs (Android App Bundles). AAB files only defer the APK generation process to the Play Store. So, APKs are still very important.
This brings us to an interesting question – how does the Google Play Store install an app?
The contents of an APK file
What does an APK file consist of? We all know that APKs are a compressed and packaged form of mobile apps. They contain a large number of bits of code that combine to form a mobile app on an Android device.
What are the contents of an APK file? Let’s review the main files included in a typical APK file.
1. META-INF directory
The meta-information directory contains a wide range of resources such as manifest files, application certificates, etc.
a. MANIFEST.MF – The manifest file contains information about other components of an APK file. The manifest in an APK file provides an overview of the content of an APK file.
b. App certificate – App certificate is an important part of an APK file. It helps the Google Play Store to uniquely identify the mobile app. Application certificate is generated only once. Therefore, developers should keep it safe for all subsequent iterations of the application.
J. CERT.SF provides a list of all resources contained in an APK file. It also details the specific locations where resources are listed in the manifest file.
is a separate directory that contains resources that come into play based on the platform the device is running on. The LIB contains separate bits of code for different types of processors.
3. Resources. arc
A file containing all the resources already compiled by the developers. This is to ensure that these resources are readily available when the application is active. For example, binary XML files are stored in this file as precompiled resources.
A file containing resources that are not compiled and remain outside of the Resources. arc file.
There are many resources that an application needs to perform some key task. The Assets file contains the code that enables the application to perform certain key tasks.
6. Classes. dex
This DEX file contains the final code executed by Android. Each small code in the APK file is converted to bits and executed in the classes.dex file.
This manifest file provides information such as program name, version number, license information, etc. You can convert this file to binary XML to read its contents.
These are the main contents of a typical APK file. Each performs a specific function during the installation and overall performance of an Android application.
Install APK via Google Play
Most of us Android users usually download apps from the Google Play Store. e
Meh, we’re familiar with the process – find an app and hit install.
A whole machine works behind the scenes, which starts when you download an app from the Google Play Store. The following section describes the process in full detail.
What happens when you press Install on the Google Play Store?
A recent study shows that users have an average of forty mobile apps on their smart devices. This means that on average, Android users press the install button on the Google Play Store at least forty times.
What happens in the background when you press the “install” button? The following steps explain what happens in the background when an app is installed on your Android device.
1. Play Store starts downloading APK files in your device memory.
2. You do not have the right to open this file. You can get read/write permission only after rooting your android device.
3. After the download is finished, your device will start the installation process. The APK will be automatically removed from your storage.
4. Your program is ready to use.
The above process removes the need for APK. Even Play Store installs an app on the device with the help of an APK file. So, even a person building an app using an app builder should have good knowledge about APK files.
Install APK from other platforms
The process is slightly different when you download an APK directly from platforms like APKPure and APKMirror.
As in the Google P store
lay happens, first, you need to download the APK file. However, once the download is complete, the installation process is not automatic. Users need to open the APK file and manually start the installation process. After the installation is complete, users can use the application in the normal way.
Can you delete the APK file after installation? Yes. Deleting the APK file will not affect the performance of the app after installation. Users must manually remove the APK from their device. Unlike app downloads from the Play Store, APK files are not automatically deleted after installation.
Additionally, you may have to change your app settings to enable APK installation. By default, Android prohibits app installation from any source other than the Google Play Store.
This brings us to an interesting question. Is it safe to download APK files from sources other than the Play Store?
Downloading popular apps can be considered safe as most APK stores import files and app listings from the Play Store. Do not download untested apps via APK. It’s generally best to download through the Play Store, as every app offered on the platform passes some level of malware testing.
Create an APK file
Designing an APK file is not that difficult. You can design an APK file using Android Studio, an integrated development environment (IDE) available for Android software developers. It is available for Windows, Mac, and Linux and allows users to design APK apps for the Google Play Store.
There are various languages for developing Android applications. Java, Kotlin, and C# are among them. Java is the official language of Android development and is supported by Android Studio. Kotlin is another official Android language. It’s similar to Java in many ways, but a little more convenient.
An APK file contains all the code and assets of a software application. Developers creating apps for use on Android devices must compile their apps into APK format before uploading them to Google Play, the official Android app marketplace.
The installation of APK files downloaded from Google Play is done automatically, that’s why users are usually unaware of the content of the files. In this article, information was given about the content and how to install these files.
It should be noted that Google has recently launched AABs to compress the size of files that users have to download from the Play Store. AABs defer the creation of the APK to the Play Store and increase the speed of app installation. To know more about the difference between APK and AAB files, see the difference between APK and AAB files.