Development of interaction with mobile devices user – key principles


There is one the most vital thing to be remembered developing a mobile application is its being both useful and intuitively comprehensible. If the application is not beneficial, it means that any practical value and motivation to use it are absent for the user. If the application is considered useful but it takes much time and effort to teach to work with it, people will also refuse from it.

A good development of any user interface decides both existing design problems:

So that the app could be useful, mobile application must be fully oriented on the user. He installs your application because he needs to decide an important for him problem. In this case, the application has a distinctly defined “understanding of the objective”. Think about the fact that these are your users, who will try to perform, concentrate on their key objectives and take away all the obstacles from the leading to them way.

– A user interface must be completely comprehensible. To use a developed by you interface effectively there must be an opportunity provided to easily understand what for and how it could be used. There shouldn’t be even the tiniest place for any confusion.

There are 9 principles of development that are to my mind key ones in providing a really high-quality interaction with the user mentioned lower.

1. Don’t permit overloading

User’s attention is a valuable resource and it must be distributed in a corresponding way. Overloading of the interface provides your user with the abundance of information: every newly added button, image or text line make the screen picture more complicated.

Overloading is a drawback in the software for a computer or site, but in the mobile device, it has even more serious consequences. The image was received from train

There is a very famous quotation offered by Antoine de Saint-Exupéry: “Perfection is achieved not when there is nothing to add, but when there is nothing to take away.” In the mobile app, it is of great importance to get rid everything that is hardly necessary; a decrease in load improves understanding.

There is an empiric rule: only one main action must be in every window. Each window developed by you for an application must support only one single action that is valuable to the user. It eases teaching process, use and addition or incorporating if necessary. It is better to have one hundred well-thought in loading windows than to have the one filled down to the limit.

Take Uber, for example. Uber is aware of the target of this application user is to order a taxi. That is why the application does not load the user with any other info: it automatically determines the exact location of the sending device based on the satellite data and the user is obliged to choose only the final destination point.

One of the main rules of providing good interaction with the user is a decrease in the number of user’s efforts on his way to the desirable result.

2. Provide with the intuitively comprehensible navigation

To help a user in navigation must be a priority for every application. A good navigation must be felt like a non-visible hand that directs user on his way. In the end, even the coolest characteristic or the most attractive content are useless unless people can find them. These are principles of good navigation in the app for any mobile device:

– Navigation must be clear. It is a necessity to use suitable symbols (right visual characters) so that no explanations were required and it is vital to guarantee that every element of navigation (such one as an icon, for example) could lead to the necessary destination.

– Navigation in the application for any mobile device must be consistent in the whole app. Do not allow to locate elements of navigation direction on different pages in different places or their absence at all. It will greatly complicate use’s actions.

– Navigation must provide a user with the information about his current location in the app. The absence of such an indication is, obviously, one of the most widely spread mistakes that are met in many menus of apps. “Where am I?” – one of the main questions the answer to which is required by users while navigation.

3. Provide an elaborate interaction

It is forbidden to think of the development of navigation in the app for a mobile device in isolation. The creation of an elaborate interaction between mobile, table and tablet devices has a very important meaning for your users.

For example, you can take Apple Music. As soon as your playlist is put on your Mac, it immediately will become available on the iPhone too. Apple realizes that at the time when a structure of the mobile application has an extremely great importance, an elaborate interaction between iPhone, Mac and IPad is also so important for all users.

4. Develop sensor control elements for them to be comfortable for fingers

It is easier for users to deal with huge sensor control elements than with small ones. With the development of mobile devices interfaces, it is better to make control elements quite sizable so that it could be easier to fit them.

Sizes of the control elements must be 7-10 mm so that a finger could cover it accurately. Such an element allows a user to place his finger comfortably inside it. The edges of the element will be seen around the finger. It guarantees a user a clear feedback that shows that the contact with the control element is provided.

Elements of each user interface control panel must be quite sizable to be able to register the touch of the fingertip distinctly without creating obstructions for a user with not ordinary reaction and small sizes. The image was received from Apple.

It is necessary also to provide a sufficient distance between sensor elements.

5. Texts must be comfortable to read

Screens of smartphones are not large in comparison with table computers that is why one of the problems of their apps development is the location of required information on the small interface. There is always a temptation to contract everything to provide a maximal amount of information. Don’t give in to this temptation.

There is an empiric rule for mobile devices: text must have size at least of 11 points so that it could be readable at the typical viewing distance that is unnecessary to zoom up.

The image was received from Apple.

It is a necessity to improve comfort of reading by the increase in the line height or interval between signs. A good space exceeding the average point can make difficult to read interfaces more attractive and simple.

A good user interface looks spacious. The image was received from Apple.

6. Try to make vital interface elements well visible

Usage of color and contrast can help users see and understand your content. You can choose primary as well as secondary and accent colors in the way that they could contribute to the comfort of usage. Make a sufficient color contrast especially between elements so that your application could be seen and used by users with weak eyesight.

Provide contrast between the main color of font and background for the text to be comfortable to read. W3C doe recommend the following figures of contrast for the main text and text on the image:

– Small text must have a contrast of at least 4.5:1 in regard to the background.

– Big text (beginning with 14 points for semi-bold and 18 points for an ordinary one) must have a contrast of at least 3:1 in regard to the background.

The text that does not correspond with the recommendations in color contrast is quite difficult to read. The image was received from Apple.

It is extremely of great importance to have a sufficient contrast on the mobile device too: being in the open air contrast can be low because of bad lighting.

The neutral gray color of this page looks well inside the room but locating in the open air the impression is different. The image was received during the tests.

Pictograms or any other critical elements must also use recommended above contrast figures.

Pictograms that do not correspond with the color contrast recommendations are more difficult to distinguish in the background. The image was received from the instruction in Material Design.

7. Develop control elements in accordance with the hand position

Stephen Huber has shown in his research of mobile devices use that 49 percent of people rely only on the thumb to make any operations on their phones. On the image lower you can see areas depicted on the screens of mobile phones approximately inform with the color what parts of the screen can be reached with the user’s thumb to interact with them.

Comfortable zones for smartphone control using one finger. The image was received from UXmatters.


The green area can be reached by the user easily; yellow areas require some tension and to reach red area user must change the device position in his hand. The hand position and grasp must be taken into consideration when you locate control elements of the mobile device:

– It is of great importance to locate the menu of the upper level, often used control elements and elements of typical actions in the green zone on the screen as they would be easily reached using one finger.

Typical tumbler actions. The image was received from Capptivate.

– Critical actions (such ones as deleting or erasing, for example) should be placed in the difficult to access red zone to make their accidental start more difficult.

8. Minimize the necessity to type using keyboard

Keyboard typing on the mobile device is a slow process that often results in mistakes. Consequently, it is always better to minimize the quantity of keyboard typing necessary for mobile app use:

– Forms should be maximally short and simple and contain only very necessary fields.

There are no people, who would like to fill in the forms. And remember, the longer and more complex the form see, there are the fewer opportunities that the user will enter it again and start fill in the blanks. The image was received from Lukew.

– Use automatic filling and personalized data there where there is a possibility to do so that only a minimum of some information was required to be filled in by the user.

A field with automatic filling for a country, for example.

9. Test your development

It happens extremely often that a mobile app looks great on the big screen of the laptop but it turns out that it is several times worse testing it on the real mobile device. It seems that even the most thoroughly worked out a product of the interaction with the user will consequently have some defect that will be apparent during the conditions of real use.Consequently, it is extremely of great importance to test your app among real users on numerous mobile devices. You must ask more real users to perform their regular tasks; only then you might be able to understand how well your development functions in reality. Consider your application as a constantly developing object using analytics data and users’ feedbacks to improve interaction constantly.


Together with any other elements of developments mentioned above pieces of advice are only a starting point for considerations. Unite and coordinate these ideas with yours to get the best possible results. Always remember that every project is aimed at users first of all, not at developers.

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