Android 4 may refer to:
Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen mobile devices such as smartphones and tablets. Android has historically been developed by a consortium of developers known as the Open Handset Alliance, but its most widely used version is primarily developed by Google. It was unveiled in November 2007, with the first commercial Android device, the HTC Dream, being launched in September 2008.
A mobile operating system is an operating system used for smartphones, tablets, smartwatches, smartglasses, or other non-laptop personal mobile computing devices. While computers such as typical/mobile laptops are "mobile", the operating systems used on them are usually not considered mobile, as they were originally designed for desktop computers that historically did not have or need specific mobile features. This "fine line" distinguishing mobile and other forms has become blurred in recent years, due to the fact that newer devices have become smaller and more mobile, unlike the hardware of the past. Key notabilities blurring this line are the introduction of tablet computers, light laptops, and the hybridization of the two in 2-in-1 PCs.
Google I/O, or simply I/O, is an annual developer conference held by Google in Mountain View, California. The name "I/O" is taken from the number googol, with the "I" representing the first digit "1" in a googol and the "O" representing the second digit "0" in the number. The format of the event is similar to Google Developer Day.
The Android Package with the file extension apk is the file format used by the Android operating system, and a number of other Android-based operating systems for distribution and installation of mobile apps, mobile games and middleware. A file using this format can be built from source code written in either Java or Kotlin.
CyanogenMod is a discontinued open-source operating system for mobile devices, based on the Android mobile platform. Developed between 2009 and 2016, it was free and open-source software based on the official releases of Android by Google, with added original and third-party code, and based on a rolling release development model. Although only a subset of total CyanogenMod users elected to report their use of the firmware, on 23 March 2015, some reports indicated that over 50 million people ran CyanogenMod on their phones. It was also frequently used as a starting point by developers of other ROMs.
The version history of the Android mobile operating system began with the public release of its first beta on November 5, 2007. The first commercial version, Android 1.0, was released on September 23, 2008.
The operating system is developed by Google on a yearly cadence since at least 2011. New major releases are announced at Google I/O in May while still in beta testing with the stable version usually released to the public between August and October.

Android software development is the process by which applications are created for devices running the Android operating system. Google states that "Android apps can be written using Kotlin, Java, and C++ languages" using the Android software development kit (SDK), while using other languages is also possible. All non-Java virtual machine (JVM) languages, such as Go, JavaScript, C, C++ or assembly, need the help of JVM language code, that may be supplied by tools, likely with restricted API support. Some programming languages and tools allow cross-platform app support. Third party tools, development environments, and language support have also continued to evolve and expand since the initial SDK was released in 2008. The official Android app distribution mechanism to end users is Google Play; it also allows staged gradual app release, as well as distribution of pre-release app versions to testers.
The Samsung Galaxy R (Royal) (GT-I9103) is an Android smartphone that was announced by Samsung on August 10, 2011 as a variant to the Samsung Galaxy S II.

The Android lawn statues are a series of large foam statues near the Googleplex in Mountain View, California, currently located at Charleston Rd & Huff Ave. They are based on the code names for versions of Google's Android mobile operating system, which were named after desserts and sweet treats. Google used to commission a statue for each new Android version, a tradition that ended in 2019 after the release of Android 10. Starting with Android 11, the statues are created as virtual 3D models.

BlueStacks is a chain of cloud-based cross-platform products developed by the San Francisco-based company of the same name. The BlueStacks App Player enables the execution of Android applications on computers running Microsoft Windows or macOS.
Aptoide is an online marketplace for mobile applications which runs on the Android and iOS operating systems. In Aptoide, unlike the Android-default Play Store and iOS-default App Store, there is not a unique and centralized store; instead, each user manages their own store. The software package is published by Aptoide S.A., a for-profit company incorporated in 2011, and headquartered in Lisbon, Portugal.
Nexus 5 is an Android smartphone sold by Google and manufactured by LG Electronics. It is the fifth generation of the Nexus series, succeeding the Nexus 4. It was unveiled on October 31, 2013 and served as the launch device for Android 4.4 "KitKat", which introduced a refreshed interface, performance improvements, greater Google Now integration, and other changes. Much of the hardware is similar to the LG G2 which was also made by LG and released earlier that year.
Kotlin is a cross-platform, statically typed, general-purpose high-level programming language with type inference. Kotlin is designed to interoperate fully with Java, and the JVM version of Kotlin's standard library depends on the Java Class Library, but type inference allows its syntax to be more concise. Kotlin mainly targets the JVM, but also compiles to JavaScript or native code via LLVM. Language development costs are borne by JetBrains, while the Kotlin Foundation protects the Kotlin trademark.
Stagefright is the name given to a group of software bugs that affect versions from 2.2 "Froyo" up until 5.1.1 "Lollipop" of the Android operating system exposing an estimated 950 million devices at the time. The name is taken from the affected library, which among other things, is used to unpack MMS messages. Exploitation of the bug allows an attacker to perform arbitrary operations on the victim's device through remote code execution and privilege escalation. Security researchers demonstrate the bugs with a proof of concept that sends specially crafted MMS messages to the victim device and in most cases requires no end-user actions upon message reception to succeed—the user doesn't have to do anything to 'accept' exploits using the bug; it happens in the background. A phone number is the only information needed to carry out the attack.
Android Nougat is the seventh major version and 14th original version of the Android operating system. First released as an alpha test version on March 9, 2016, it was officially released on August 22, 2016, with Nexus devices being the first to receive the update.
Google Assistant is a virtual assistant software application developed by Google that is primarily available on home automation and mobile devices. Based on artificial intelligence, Google Assistant can engage in two-way conversations, unlike the company's previous virtual assistant, Google Now.
Android Oreo is the eighth major release and the 15th version of the Android mobile operating system.
EMUI is an interface based on Android developed by Chinese technology company Huawei, used on the company's smartphones primarily globally.
Android 1.x may refer to:
HarmonyOS (HMOS) is a distributed operating system developed by Huawei for smartphones, tablets, smart TVs, smart watches, personal computers and other smart devices. It has a multi-kernel design with dual frameworks: the operating system selects suitable kernels from the abstraction layer in the case of devices that use diverse resources.