Designing Mobile Apps
Index of contents


The following pages provide a more detailed explanation of some of the terms used in this book. Although, in some occurrences, the meaning of certain terms can go beyond the context of apps, we have decided to narrow down the scope of the descriptions to our area of concern.


The ability to access content, regardless of a person’s physical capacities. At a visual level, accessibility is determined by the size of text and buttons and by the contrast of those elements against the background. An accessible app also refers to correct code programming that allows, for example, for content to be interpreted by accessories for people with visual disabilities.


The name most commonly used to refer to a certain kind of software; an abbreviation of the word application. An app is a piece of software that is executed in mobile phones and tablets and is our object of study.


The systematic practice used to evaluate products, services and processes in a comparable manner. In our context, it’s the comparative and analytical study of other applications to determine their quality and characteristics, using them as parameters for reference.


The action of packaging a code. As a result of compiling an application’s code, the final file is ready to be uploaded to the store.

Context of Use

General environment that consists of the location and physical space around the user and the device. Context of use also determines the way in which these two components relate and interact with one other.


Acronym for Cascading Style Sheets. Whether in separate files or inside HTML code, this language determines the visual appearance of a web application and defines font color and size.


Acronym for density-independent pixels; a unit of measure used by Android in relation to the screen’s physical density. DPs are units relevant to 160 DPI screens, in which a DP is equal to one pixel.

Using DP instead of pixels is a solution suggested to correctly adapt an interface for use in screens with different densities.


The answer from the interface to keep the user informed about the actions he or she has just performed. Generally immediate. Feedback can be a confirmation of success or an error message obtained when executing a certain task, and it can manifest itself by means of notifications or much more subtle visual elements.


Acronym for HyperText Markup Language. The language traditionally used to build web pages and web applications for mobile devices. It defines the structure of a web document based in a series of tags.

Interfaz or UI

The layer in between a device and a user that allows them to interact. In applications, interface makes reference to the graphic component containing elements that produce reactions when touched and that allow the user to perform tasks, and also to those static components that facilitate the interpretation of content.


Programming language used mainly for web projects like sites and applications. Often interacts with HTML and CSS to provide more functionality.


Acronym for Key Performance Indicator. KPI measures the variables that are being executed in a project with the aim of obtaining relevant data to determine general performance and decipher whether set goals have been accomplished.


In programming, this name is given to the set of external codes that can be used to cause certain behaviors. Directly related to the programming language chosen.

Mobile Device

Also called cell phone, an electronic device of variable size where applications function. You’ve probably got one with you now.


The action of obtaining an economic profit. In an application, this is related to the different ways of obtaining income from an app is also directly tied to business model and commercial strategy.

Operating System or OS

The software contained in each telephone where applications are executed. The different versions of Android, iOS and Windows Phone are examples of operating systems.


The way content is displayed on a screen according to how the user is holding a device (tablet or smartphone). Portrait or landscape.


Personification of users as the result of studies based on their behaviors and ethnographic characteristics. This investigation is based on the common patterns detected in users. The concept of Persona was created by Cooper and is a common tool for interaction design.

Pixel or PX

Physical units made up of colored dots that are spread across a screen surface. In design, pixels are used as units of measure for the graphic components of an interface in different editing programs.


Ordered classification in which the stores sort applications according to factors like number of downloads and positive reviews.


The combination of context of use and Persona. It determines how the user relates to the mobile device in a specific situation.

Screen Density

Quantity of pixels per physical space in a screen. Generally measured in DPI (dots per inch). Densities may vary from one device model to another and in general can be grouped by low, medium and high, depending on the operating system.

Screen Resolution

The number of pixels that can be shown on a device’s screen. It consists of the width and height relation.

Screen Size

The physical size of the screen from one edge to the other, measured diagonally and in inches.


Acronym for Software Development Kit. An SDK provides programmers with the necessary tools for developing an application’s code. Offered by Android, iOS and Windows Phone.


A simulator makes it possible to test an application without a mobile device. Code may be executed in a computer, and results can be visualized on the screen to perform preliminary checks on an app’s functioning.


In Android, the acronym for scale-independent pixels used for texts. In design, they behave in the same way as DPs, the only difference being that the size measured in SP can also be affected by user preferences.


The application distribution and marketing channel for free and paid downloads. Each mobile operating system mentioned in this book has an official store; however, in the case of Android, there are several other alternatives besides Google Play, for example, Amazon and Samsung app stores.


Combination of colors used by Android and Windows Phone by default. In Windows Phone, the user can choose from a selection of themes that affect background colors and standout elements in all screens of the operating system.


In a much broader sense, usability is related to the application interface’s effectiveness and efficiency in allowing a determined user to perform a task or accomplish a goal. Usability cannot be analyzed in isolation and is tied to a particular context and specific user. It is directly associated with user experience.


The user is the individual who interacts by means of the interface. The user is the focus of user-centered design, which is based on the principles of meeting the user’s needs. Its main goal is to come up with solutions that solve problems, taking into consideration emotions and expectations.


Concentrates the emotions or perceptions of a person when using an interface or product. In the case of apps, UX is influenced by a group of factors that determine whether the experience is positive or negative, including accessibility, visual design, interaction design and usability.