Model–view–controller ( MVC ) is a software design pattern commonly used for developing user interfaces that divides the related program logic into three interconnected elements. These elements are:
70-505: Traditionally used for desktop graphical user interfaces (GUIs), this pattern became popular for designing web applications . Popular programming languages have MVC frameworks that facilitate the implementation of the pattern. One of the seminal insights in the early development of graphical user interfaces, MVC became one of the first approaches to describe and implement software constructs in terms of their responsibilities . Trygve Reenskaug created MVC while working on Smalltalk -79 as
140-439: A secure and private data transfer. Web pages usually contain hyperlinks to other pages and resources. Each link contains a URL, and when it is clicked or tapped , the browser navigates to the new resource. Most browsers use an internal cache of web page resources to improve loading times for subsequent visits to the same page. The cache can store many items, such as large images, so they do not need to be downloaded from
210-465: A user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on a range of devices, including desktops , laptops , tablets , and smartphones . By 2020, an estimated 4.9 billion people had used a browser. The most-used browser is Google Chrome , with a 67% global market share on all devices, followed by Safari with 18%. A web browser
280-470: A GUI and some level of a CLI, although the GUIs usually receive more attention. GUI wrappers find a way around the command-line interface versions (CLI) of (typically) Linux and Unix-like software applications and their text-based UIs or typed command labels. While command-line or text-based applications allow users to run a program non-interactively, GUI wrappers atop them avoid the steep learning curve of
350-410: A combination of technologies and devices to provide a platform that users can interact with, for the tasks of gathering and producing information. A series of elements conforming a visual language have evolved to represent information stored in computers. This makes it easier for people with few computer skills to work with and use computer software. The most common combination of such elements in GUIs
420-413: A controller on the server, and the controller communicates with the appropriate model objects. The Django framework (July 2005, for Python ) put forward a similar "model template view" (MTV) take on the pattern, in which a view retrieves data from models and passes it to templates for display. Both Rails and Django debuted with a strong emphasis on rapid deployment, which increased MVC's popularity outside
490-725: A general " programming paradigm and methodology" for Smalltalk-80 developers. However, their scheme differed from both Reenskaug et al.'s and that presented by the Smalltalk-80 reference books. They defined a view as covering any graphical concern, with a controller being a more abstract, generally invisible object that receives user input and interacts with one or many views and only one model. The MVC pattern subsequently evolved, giving rise to variants such as hierarchical model–view–controller (HMVC), model–view–adapter (MVA), model–view–presenter (MVP), model–view–viewmodel (MVVM), and others that adapted MVC to different contexts. The use of
560-505: A grid of items with rows of text extending sideways from the icon. Multi-row and multi-column layouts commonly found on the web are "shelf" and "waterfall". The former is found on image search engines , where images appear with a fixed height but variable length, and is typically implemented with the CSS property and parameter display: inline-block; . A waterfall layout found on Imgur and TweetDeck with fixed width but variable height per item
630-485: A model represents some part of the program purely and intuitively. A view is a visual representation of a model, retrieving data from the model to display to the user and passing requests back and forth between the user and the model. A controller is an organizational part of the user interface that lays out and coordinates multiple Views on the screen, and which receives user input and sends the appropriate messages to its underlying Views. This design also includes an Editor as
700-459: A pattern where an "input controller" receives a request, sends the appropriate messages to a model object, takes a response from the model object, and passes the response to the appropriate view for display. This is close to the approach taken by the Ruby on Rails web application framework (August 2004), which has the client send requests to the server via an in- browser view, these requests are handled by
770-506: A program was busy. Additionally, it was the first GUI to introduce something resembling Virtual Desktops . Windows 95 , accompanied by an extensive marketing campaign, was a major success in the marketplace at launch and shortly became the most popular desktop operating system. In 2007, with the iPhone and later in 2010 with the introduction of the iPad , Apple popularized the post-WIMP style of interaction for multi-touch screens, and those devices were considered to be milestones in
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#1733106147074840-403: A response using a view. Conventionally, each view has an associated controller; for example, if the application had a client view, it would typically have an associated Clients controller as well. However, developers are free to make other kinds of controllers if they wish. Django calls the object playing this role a "view" instead of a controller. A Django view is a function that receives
910-474: A retail store, airline self-ticket and check-in, information kiosks in a public space, like a train station or a museum, and monitors or control screens in an embedded industrial application which employ a real-time operating system (RTOS). Cell phones and handheld game systems also employ application specific touchscreen GUIs. Newer automobiles use GUIs in their navigation systems and multimedia centers, or navigation multimedia center combinations. A GUI uses
980-519: A section in the menu for deleting cookies. Finer-grained management of cookies usually requires a browser extension . The first web browser, called WorldWideWeb , was created in 1990 by Sir Tim Berners-Lee . He then recruited Nicola Pellow to write the Line Mode Browser , which displayed web pages on dumb terminals . The Mosaic web browser was released in April 1993, and was later credited as
1050-414: A short sequence of words and symbols. Custom functions may be used to facilitate access to frequent actions. Command-line interfaces are more lightweight , as they only recall information necessary for a task; for example, no preview thumbnails or graphical rendering of web pages. This allows greater efficiency and productivity once many commands are learned. But reaching this level takes some time because
1120-401: A specialized kind of controller used to modify a particular view, and which is created through that view. Smalltalk-80 supports a version of MVC that evolved from this one. It provides abstract view and controller classes as well as various concrete subclasses of each that represent different generic widgets . In this scheme, a View represents some way of displaying information to
1190-428: A system or moved about to different places during redesigns. Also, icons and dialog boxes are usually harder for users to script. WIMPs extensively use modes , as the meaning of all keys and clicks on specific positions on the screen are redefined all the time. Command-line interfaces use modes only in limited forms, such as for current directory and environment variables . Most modern operating systems provide both
1260-417: A table in the application's database . The model is essential for keeping the data organized and consistent. It ensures that the application's data behaves according to the defined rules and logic. Any representation of information such as a chart , diagram or table. Multiple views of the same information are possible, such as a bar chart for management and a tabular view for accountants . In Smalltalk-80,
1330-413: A view is just a visual representation of a model, and does not handle user input. With WebObjects, a view represents a complete user interface element such as a menu or button, and does receive input from the user. In both Smalltalk-80 and WebObjects, however, views are meant to be general-purpose and composable . With Rails and Django, the role of the view is played by HTML templates, so in their scheme
1400-422: A view specifies an in-browser user interface rather than representing a user interface widget directly. (Django opts to call this kind of object a "template" in light of this.) This approach puts relatively less emphasis on small, composable views; a typical Rails view has a one-to-one relationship with a controller action. Smalltalk-80 views communicate with both a model and a controller, whereas with WebObjects,
1470-495: A view talks only to a controller, which then talks to a model. With Rails and Django, a view/template is used by a controller/view when preparing a response to the client. Accepts input and converts it to commands for the model or view. A Smalltalk-80 controller handles user input events, such as button presses or mouse movement. At any given time, each controller has one associated view and model, although one model object may hear from many different controllers. Only one controller,
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#17331061470741540-515: A visiting scientist at the Xerox Palo Alto Research Center (PARC) in the late 1970s. He wanted a pattern that could be used to structure any program where users interact with a large, convoluted data set . His design initially had four parts: Model , view, thing, and editor. After discussing it with the other Smalltalk developers , he and the rest of the group settled on model, view, and controller instead. In their final design,
1610-500: A web request and returns a web response. It may use templates to create the response. In addition to dividing the application into a model, a view and a controller component, the MVC design pattern defines the interactions between these three components : As with other software patterns, MVC expresses the "core of the solution" to a problem while allowing it to be adapted for each system. Particular MVC designs can vary significantly from
1680-664: Is a related technology that promises to deliver the representation benefits of 3D environments without their usability drawbacks of orientation problems and hidden objects. In 2006, Hillcrest Labs introduced the first ZUI for television. Other innovations include the menus on the PlayStation 2 , the menus on the Xbox , Sun's Project Looking Glass , Metisse , which was similar to Project Looking Glass, BumpTop , where users can manipulate documents and windows with realistic movement and physics as if they were physical documents, Croquet OS , which
1750-460: Is based on Mozilla 's code. Both of these codebases are open-source, so a number of small niche browsers are also made from them. The most popular browsers share many features in common. They automatically log users' browsing history , unless the users turn off their browsing history or use the non-logging private mode . They also allow users to set bookmarks , customize the browser with extensions , and can manage user passwords . Some provide
1820-405: Is built for collaboration, and compositing window managers such as Enlightenment and Compiz . Augmented reality and virtual reality also make use of 3D GUI elements. 3D GUIs have appeared in science fiction literature and films , even before certain technologies were feasible or in common use. Web browser A web browser is an application for accessing websites . When
1890-417: Is especially common with applications designed for Unix-like operating systems. The latter used to be implemented first because it allowed the developers to focus exclusively on their product's functionality without bothering about interface details such as designing icons and placing buttons. Designing programs this way also allows users to run the program in a shell script . Many environments and games use
1960-404: Is not the same thing as a search engine , though the two are often confused. A search engine is a website that provides links to other websites. However, to connect to a website's server and display its web pages, a user must have a web browser installed. In some technical contexts, browsers are referred to as user agents . The purpose of a web browser is to fetch content and display it on
2030-655: Is represented by rotating a cube with faces representing each user's workspace, and window management is represented via a Rolodex -style flipping mechanism in Windows Vista (see Windows Flip 3D ). In both cases, the operating system transforms windows on-the-fly while continuing to update the content of those windows. The GUI is usually WIMP-based, although occasionally other metaphors surface, such as those used in Microsoft Bob , 3dwm, File System Navigator, File System Visualizer , 3D Mailbox, and GopherVR . Zooming (ZUI)
2100-440: Is the windows, icons, text fields, canvases, menus, pointer ( WIMP ) paradigm, especially in personal computers . The WIMP style of interaction uses a virtual input device to represent the position of a pointing device's interface , most often a mouse , and presents information organized in windows and represented with icons . Available commands are compiled together in menus, and actions are performed making gestures with
2170-551: Is usually implemented by specifying column-width: . Smaller app mobile devices such as personal digital assistants (PDAs) and smartphones typically use the WIMP elements with different unifying metaphors, due to constraints in space and available input devices. Applications for which WIMP is not well suited may use newer interaction techniques , collectively termed post-WIMP UIs. As of 2011, some touchscreen-based operating systems such as Apple's iOS ( iPhone ) and Android use
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2240-681: The Xerox Star . These early systems spurred many other GUI efforts, including Lisp machines by Symbolics and other manufacturers, the Apple Lisa (which presented the concept of menu bar and window controls ) in 1983, the Apple Macintosh 128K in 1984, and the Atari ST with Digital Research 's GEM , and Commodore Amiga in 1985. Visi On was released in 1983 for the IBM PC compatible computers, but
2310-407: The client and server . Early MVC frameworks took a thin client approach that placed almost the entire model, view and controller logic on the server. In this approach, the client sends hyperlink requests or form submissions to the controller and then receives a complete and updated web page (or other document) from the view; the model exists entirely on the server. Later frameworks have allowed
2380-498: The cursor (or rather pointer ) control: mouse , pointing stick , touchpad , trackball , joystick , virtual keyboards , and head-up displays (translucent information devices at the eye level). There are also actions performed by programs that affect the GUI. For example, there are components like inotify or D-Bus to facilitate communication between computer programs. Ivan Sutherland developed Sketchpad in 1963, widely held as
2450-408: The most popular browser. Microsoft debuted Internet Explorer in 1995, leading to a browser war with Netscape. Within a few years, Microsoft gained a dominant position in the browser market for two reasons: it bundled Internet Explorer with its popular Windows operating system and did so as freeware with no restrictions on usage. The market share of Internet Explorer peaked at over 95% in
2520-408: The "active" controller, receives user input at any given time; a global window manager object is responsible for setting the current active controller. If user input prompts a change in a model, the controller will signal the model to change, but the model is then responsible for telling its views to update. In WebObjects, the views handle user input, and the controller mediates between the views and
2590-616: The 1970s, Engelbart's ideas were further refined and extended to graphics by researchers at Xerox PARC and specifically Alan Kay , who went beyond text-based hyperlinks and used a GUI as the main interface for the Smalltalk programming language , which ran on the Xerox Alto computer , released in 1973. Most modern general-purpose GUIs are derived from this system. The Xerox PARC GUI consisted of graphical elements such as windows , menus , radio buttons , and check boxes . The concept of icons
2660-506: The GUIs advantages, many reviewers questioned the value of the entire concept, citing hardware limits, and problems in finding compatible software. In 1984, Apple released a television commercial which introduced the Apple Macintosh during the telecast of Super Bowl XVIII by CBS , with allusions to George Orwell 's noted novel Nineteen Eighty-Four . The goal of the commercial was to make people think about computers, identifying
2730-531: The MVC components to execute partly on the client, using Ajax to synchronize data. Graphical user interface A graphical user interface , or GUI ( / ˈ ɡ uː i / GOO -ee ), is a form of user interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation . In many applications, GUIs are used instead of text-based UIs , which are based on typed command labels or text navigation. GUIs were introduced in reaction to
2800-699: The MVC pattern in web applications grew after the introduction of NeXT 's WebObjects in 1996, which was originally written in Objective-C (that borrowed heavily from Smalltalk) and helped enforce MVC principles. Later, the MVC pattern became popular with Java developers when WebObjects was ported to Java . Later frameworks for Java, such as Spring (released in October 2002), continued the strong bond between Java and MVC. In 2003, Martin Fowler published Patterns of Enterprise Application Architecture , which presented MVC as
2870-405: The advantages of Smalltalk-80-style MVC as: Although originally developed for desktop computing , MVC has been widely adopted as a design for World Wide Web applications in major programming languages . Several web frameworks have been created that enforce the pattern. These software frameworks vary in their interpretations, mainly in the way that the MVC responsibilities are divided between
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2940-513: The basis for many other browsers, including Microsoft Edge , currently in third place with about a 5% share, as well as Samsung Internet and Opera in fifth and sixth places respectively with over 2% market share each. The other two browsers in the top four are made from different codebases . Safari , based on Apple 's WebKit code, is the second most popular web browser and is dominant on Apple devices, resulting in an 18% global share. Firefox , in fourth place, with about 3% market share,
3010-401: The class of GUIs named post-WIMP. These support styles of interaction using more than one finger in contact with a display, which allows actions such as pinching and rotating, which are unsupported by one pointer and mouse. Human interface devices , for the efficient interaction with a GUI include a computer keyboard , especially used together with keyboard shortcuts , pointing devices for
3080-457: The command words may not be easily discoverable or mnemonic . Also, using the command line can become slow and error-prone when users must enter long commands comprising many parameters or several different filenames at once. However, windows, icons, menus, pointer ( WIMP ) interfaces present users with many widgets that represent and can trigger some of the system's available commands. GUIs can be made quite hard when dialogs are buried deep in
3150-413: The command-line, which requires commands to be typed on the keyboard . By starting a GUI wrapper, users can intuitively interact with, start, stop, and change its working parameters, through graphical icons and visual indicators of a desktop environment , for example. Applications may also provide both interfaces, and when they do the GUI is usually a WIMP wrapper around the command-line version. This
3220-571: The designer's work to change the interface as user needs evolve. Good GUI design relates to users more, and to system architecture less. Large widgets, such as windows , usually provide a frame or container for the main presentation content such as a web page, email message, or drawing. Smaller ones usually act as a user-input tool. A GUI may be designed for the requirements of a vertical market as application-specific GUIs. Examples include automated teller machines (ATM), point of sale (POS) touchscreens at restaurants, self-service checkouts used in
3290-485: The development of mobile devices . The GUIs familiar to most people as of the mid-late 2010s are Microsoft Windows , macOS , and the X Window System interfaces for desktop and laptop computers, and Android , Apple's iOS , Symbian , BlackBerry OS , Windows Phone / Windows 10 Mobile , Tizen , WebOS , and Firefox OS for handheld ( smartphone ) devices. Since the commands available in command line interfaces can be many, complex operations can be performed using
3360-435: The display represents a desktop, on which documents and folders of documents can be placed. Window managers and other software combine to simulate the desktop environment with varying degrees of realism. Entries may appear in a list to make space for text and details, or in a grid for compactness and larger icons with little space underneath for text. Variations in between exist, such as a list with multiple columns of items and
3430-646: The early 2000s. In 1998, Netscape launched what would become the Mozilla Foundation to create a new browser using the open-source software model. This work evolved into the Firefox browser, first released by Mozilla in 2004. Firefox's market share peaked at 32% in 2010. Apple released its Safari browser in 2003; it remains the dominant browser on Apple devices, though it did not become popular elsewhere. Google debuted its Chrome browser in 2008, which steadily took market share from Internet Explorer and became
3500-593: The first graphical computer-aided design program. It used a light pen to create and manipulate objects in engineering drawings in realtime with coordinated graphics. In the late 1960s, researchers at the Stanford Research Institute , led by Douglas Engelbart , developed the On-Line System (NLS), which used text-based hyperlinks manipulated with a then-new device: the mouse . (A 1968 demonstration of NLS became known as " The Mother of All Demos ".) In
3570-728: The first web browser to find mainstream popularity. Its innovative graphical user interface made the World Wide Web easy to navigate and thus more accessible to the average person. This, in turn, sparked the Internet boom of the 1990s, when the Web grew at a very rapid rate. The lead developers of Mosaic then founded the Netscape corporation, which released the Mosaic-influenced Netscape Navigator in 1994. Navigator quickly became
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#17331061470743640-485: The interface found in current versions of Microsoft Windows, and in various desktop environments for Unix-like operating systems , such as macOS and Linux . Thus most current GUIs have largely common idioms. GUIs were a hot topic in the early 1980s. The Apple Lisa was released in 1983, and various windowing systems existed for DOS operating systems (including PC GEM and PC/GEOS ). Individual applications for many platforms presented their own GUI variants. Despite
3710-413: The kind of data they hold. The widgets of a well-designed interface are selected to support the actions necessary to achieve the goals of users. A model–view–controller allows flexible structures in which the interface is independent of and indirectly linked to application functions, so the GUI can be customized easily. This allows users to select or design a different skin or theme at will, and eases
3780-435: The methods of 3D graphics to project 3D GUI objects onto the screen. The use of 3D graphics has become increasingly common in mainstream operating systems (ex. Windows Aero , and Aqua (MacOS)) to create attractive interfaces, termed eye candy (which includes, for example, the use of drop shadows underneath windows and the cursor ), or for functional purposes only possible using three dimensions. For example, user switching
3850-440: The models. There may be only one controller per application, or one controller per window. Much of the application-specific logic is found in the controller. In Rails, requests arriving at the on-server application from the client are sent to a " router ", which maps the request to a specific method of a specific controller. Within that method, the controller interacts with the request data and any relevant model objects and prepares
3920-508: The most popular browser in 2012. Chrome has remained dominant ever since. By 2015, Microsoft replaced Internet Explorer with Edge for the Windows 10 release. Since the early 2000s, browsers have greatly expanded their HTML , CSS , JavaScript , and multimedia capabilities. One reason has been to enable more sophisticated websites, such as web apps . Another factor is the significant increase of broadband connectivity in many parts of
3990-680: The perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on a computer keyboard . The actions in a GUI are usually performed through direct manipulation of the graphical elements. Beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls . The term GUI tends not to be applied to other lower- display resolution types of interfaces , such as video games (where head-up displays ( HUDs ) are preferred), or not including flat screens like volumetric displays because
4060-403: The pointing device. A window manager facilitates the interactions between windows, applications , and the windowing system . The windowing system handles hardware devices such as pointing devices, graphics hardware, and positioning of the pointer. In personal computers , all these elements are modeled through a desktop metaphor to produce a simulation called a desktop environment in which
4130-401: The server again. Cached items are usually only stored for as long as the web server stipulates in its HTTP response messages. During the course of browsing, cookies received from various websites are stored by the browser. Some of them contain login credentials or site preferences. However, others are used for tracking user behavior over long periods of time, so browsers typically provide
4200-509: The system never reached commercial production. The first commercially available computer with a GUI was the 1979 PERQ workstation , manufactured by Three Rivers Computer Corporation. Its design was heavily influenced by the work at Xerox PARC. In 1981, Xerox eventually commercialized the ideas from the Alto in the form of a new and enhanced system – the Xerox 8010 Information System – more commonly known as
4270-492: The term is restricted to the scope of 2D display screens able to describe generic information, in the tradition of the computer science research at the Xerox Palo Alto Research Center . Designing the visual composition and temporal behavior of a GUI is an important part of software application programming in the area of human–computer interaction . Its goal is to enhance the efficiency and ease of use for
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#17331061470744340-596: The traditional description here. As Alan Kay wrote in 2003, the original motivation behind the MVC was to allow creation of a graphical interface for any object. That was outlined in detail in Richard Pawson's book Naked Objects . Trygve Reenskaug, originator of MVC at PARC, has written that "MVC was conceived as a general solution to the problem of users controlling a large and complex data set." In their 1991 guide Inside Smalltalk , Carleton University computer science professors Wilf LaLonde and John Pugh described
4410-415: The traditional enterprise environment in which it has long been popular. The central component of the pattern. It is the application's dynamic data structure , independent of the user interface. It directly manages the data, logic and rules of the application. In Smalltalk-80, the design of a model type is left entirely to the programmer. With WebObjects, Rails, and Django, a model type typically represents
4480-456: The underlying logical design of a stored program , a design discipline named usability . Methods of user-centered design are used to ensure that the visual language introduced in the design is well-tailored to the tasks. The visible graphical interface features of an application are sometimes referred to as chrome or GUI . Typically, users interact with information by manipulating visual widgets that allow for interactions appropriate to
4550-485: The user's device. This process begins when the user inputs a Uniform Resource Locator (URL), such as https://en.wikipedia.org/ , into the browser. Virtually all URLs on the Web start with either http: or https: which means they are retrieved with the Hypertext Transfer Protocol (HTTP). For secure mode (HTTPS), the connection between the browser and web server is encrypted , providing
4620-538: The user, and a controller represents some way for the user to interact with a view . A view is also coupled to a model object, but the structure of that object is left up to the application programmer . The Smalltalk-80 environment also includes an "MVC Inspector", a development tool for viewing the structure of a given model, view, and controller side-by-side. In 1988, an article in The Journal of Object Technology (JOT) by two ex-PARC employees presented MVC as
4690-466: The user-friendly interface as a personal computer which departed from prior business-oriented systems, and becoming a signature representation of Apple products. In 1985, Commodore released the Amiga 1000 , along with Workbench and Kickstart 1.0 (which contained Intuition ). This interface ran as a separate task, meaning it was very responsive and, unlike other GUIs of the time, it didn't freeze up when
4760-405: The world, enabling people to access data-intensive content, such as streaming HD video on YouTube , that was not possible during the era of dial-up modems . Google Chrome has been the dominant browser since the mid-2010s and currently has a 67% global market share on all devices. The vast majority of its source code comes from Google's open-source Chromium project; this code is also
4830-399: Was later introduced by David Canfield Smith , who had written a thesis on the subject under the guidance of Kay. The PARC GUI employs a pointing device along with a keyboard. These aspects can be emphasized by using the alternative term and acronym for windows, icons, menus, pointing device ( WIMP ). This effort culminated in the 1973 Xerox Alto , the first computer with a GUI, though
4900-574: Was never popular due to its high hardware demands. Nevertheless, it was a crucial influence on the contemporary development of Microsoft Windows . Apple, Digital Research, IBM and Microsoft used many of Xerox's ideas to develop products, and IBM's Common User Access specifications formed the basis of the GUIs used in Microsoft Windows, IBM OS/2 Presentation Manager , and the Unix Motif toolkit and window manager . These ideas evolved to create
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