Default Values¶

Static Values
Dynamic Defaults
Dynamic Defaults in Repeats
Dynamic Images

Static Values ¶

A static default is set when the the form is first opened.

Note

To add a staric default; place the default value in the default column without using quotation marks.

Static Default:¶
type	name	label	default
select_one food_group	food_group	Which food group was this?	legumes

In the above example the default value for the select one question is set to legumes.

Special Static Defaults ¶

You can use one of these special values in the default column.

Special Static Default Values:¶
default	comment
now()	Sets a date or date-time question type to the current date/time
The name of an image in shared resources including the extension. For example: office_plans.jpg	Use this with questions of type "image". The image from shared resources will then be set as the default value and you can use an appearance of "annotate" to allow a user to edit this image.

Because a static default value is set when the form is first opened there is no point referring to the answers to other question in order to set the default value. For that you will need to use a dynamic default. However you can refer to a preload. So for example you may specify a preload to get the users name and you can then use that preload value in a static default.

Using Preloads in Static Defaults:¶
type	name	label	default
username	uname
text	uname_confirm	Confirm your name	${uname}

Referring to the last saved value ¶

If you are conducting multiple interviews where you have to enter the same answers each time then you can default the answer to the one given in the previous interview. The obvious use for this is for addresses. For example if you are interviewing 20 people in a town then the town name will be the same for each person.

Specify the following in the default column:

${last-saved#question_name}

Replace "question_name" with the name of the previously answered question that you want to get the default value from.

Example of Last Saved¶
type	name	label	default
text	street_name	Street	${last-saved#street_name}

Warning

Requires fieldTask 6.100 or above and Smap Server 20.04 or above

Dynamic Defaults ¶

A dynamic default value is specified in the calculation column for a question. Hence you can set the initial answer to a question based on the answer to a preceeding question.

Warning

Calculations in FieldTask are updated every time their source changes and also just before the survey is saved. This can cause lots of issues when using them to set default values. For example if you had a dynamic default calculation of ${number_girls} to set the default value for a question on how many girls go to school then the answer (to how many girls go to school) will be reset back to the default value when the form is saved.

To avoid the problem of recalculation of defaults when the form is saved wrap the calculation in the either the once() function or in fieldTask version 6.209 and above you can use the default() function:

once(${number_girls})
default(${number_girls})

Now the default value is set when the question is shown.

If you use the once function then after the answer has been set it will not be changed again using the default calculation.
If you use the default() function then if the dependencies of the calculation change the value will be reset however it will not be changed either when the form is saved or when the form is initialised. This latter condition is important if you are restoring from a saved survey or starting a task.

Note

Webforms does not have the above issues with dynamic defaults and you should not wrap the default calculation in the once() function. However you can use the default() function as this will just be ignored.

You can also use Triggering the Calculation to get the same result as you can set the trigger to be the referenced question from which you are getting the default. The calculation will then only be updated when that value changes.

Dynamic Defaults in Repeats ¶

You can use a entered in a previous repeat instance to calculate the default in the next repeat instance. Requires version 23.11 of the Smap Server. An "xpath" expression ise specified as the default value for a question inside a repeat. You can modify the following example to get what you need.

For example in the following survey the value of observation_id will default to "1" for the first instance and then increment by 1, for each additional repeat instance.

Survey Worksheet¶
type	name	label	default
begin repeat	observations	Observations
int	observation_id	ID	if(position(..)=1,1,(${observations}[position() = position(current()/..) - 1]/observation_id)+1)
end repeat

"${observations}" refers to the name of the repeat.
"position(current()/..) - 1" refers to a value in the previous repeat instance
"/observation_id" refers to the value in the observation_id question
"+ 1" adds one to that value

Dynamic Images ¶

You can dynamically specify an image URL as the default value of a question. If the Android device or WebForm is online this image will then be downloaded. One application of this might be if you had an image question with an appearance of annotate. The image URL can be selected from a list of drawing schematics, the selected image would then be downloaded and the user would be able to annotate the selected schematic.

Use a get_media() function to download the required URL. There are some differences between the way WebForms and FieldTask work.

WebForms ¶

For webforms the get_media() function takes 2 parameters. The first is the URL to retrieve and the second one is the path to the question that should receive the URL. This is different from the every other use of dynamic defaults in that the calculation places in the result in the specified question. Hence you don't need to have anything in the calculation column of the target question:

get_media(${q1}, '/main/q3')

Note

For the second parameter you cannot use the ${} notation. Paths to questions always start with '/main' and then continue with the names of groups and questions each separated by a '/'

Example survey for Dynamic Images (WebForm version)

FieldTask ¶

Only one parameter is required for get_media() which is the URL of the image. Then the calculation question is specified in the calculation column of the target question:

calculate  q2   if(string-length(${q1}) > 0, get_media(${q1}, ''), '')
image      q3   default(${q2})

The dynamic default value should be wrapped in a default() or once() function so that it does not get changed when the form is saved. default() is usually better as it would allow the url of the image to be re-calculated and a new image applied whereas if once() is used then once the image is set it cannot be changed without manually clearing the answer.

Example survey for Dynamic Images (FieldTask Version)

Security Considerations ¶

Security controls on the server holding the images may prevent their access within a form. So unless they are on a completely open server you will need to consider access permissions and CORS settings.

Alternatively if you are accessing images collected by other surveys on the same Smap server then you can use the Smap security controls (projects, RBAC) to control access.