[solved] Custom forms: How to activate a 'Next Button' only when a checkbox is chosen

absurd · March 2015

Hi,

I created a custom form with an inline python script. On the form there are some multiple choice checkbox widgets and a next button.
Currently, a participant can click 'Next' without having checked any of the answers/checkboxes. How can I achieve that the 'Next Button' is only active/clickable if a choice is made?

Best,
Johannes

Josh · March 2015

Hi Johannes,

It seems that there is no simple option or command to take care of this directly (based on http://osdoc.cogsci.nl/forms/form-variables/#in-custom-forms)

However, when no choice was made, the my_response_var would be set to 'no', and you can use this to your advantage. Basically, you would place your custom form in a loop item. In the loop item, check the 'advanced options' box and insert the Break if command:
=self.get('my_response_var') != 'no'. Thus, the custom form would be repeated until there is something else than a 'no'.

Of course it might be nice to add a copy of the custom form to the loop (so both forms would have to go in a sequence item that itself is placed in a loop item), with the addition of a text line such as "Please choose an option!", and for the second form insert the run-if command: =self.get('my_response_var') == 'no'.
Additionally, you would need to make an inline script (placed outside of the loop) with some code to make sure the first form isn't run if the second form is run. You can do this by making a variable, e.g. 'CHECK' and set it to False, and then write code (this time IN the loop) to set it to True if my_response_var == 'no'. Next, for the first form you would have to insert the run-if command: =self.get('CHECK') == False.

So what would happen now, is that people see a form, and if they click a button without choosing an option, a text will appear that says "Please choose an option!". The screen will only disappear (i.e. we would break out of the loop) if an option is chosen!

Hope this helps!

Cheers,

Josh

absurd · March 2015

Hi Josh,

Thanks for your help.
I tried this, but my experiment nevertheless either just proceeds if the next button is pressed or it just quits (i.e. the break command ends the loop, but the loop does not run again). Here is a minimal working example:

# Generated by OpenSesame 2.9.4 (Hesitant Heisenberg)
# Mon Mar 30 17:14:45 2015 (posix)
# <http://www.cogsci.nl/opensesame>

set background "#aaffff"
set bidi "no"
set canvas_backend "xpyriment"
set compensation "0"
set coordinates "relative"
set description "Default description"
set font_bold "no"
set font_family "mono"
set font_italic "no"
set font_size "18"
set foreground "#550000"
set height "768"
set keyboard_backend "legacy"
set mouse_backend "xpyriment"
set sampler_backend "legacy"
set start "experiment"
set subject_nr "0"
set subject_parity "even"
set synth_backend "legacy"
set title "New experiment"
set width "1024"

define inline_script _inline_script
    set _prepare ""
    set _run "exp.set('my_response_var_2','no')"

define loop _loop
    set break_if "[my_response_var_2]!='no'"
    set column_order ""
    set cycles "1"
    set item "inline_script"
    set order "sequential"
    set repeat "1"
    set skip "0"
    run inline_script

define sequence experiment
    run _inline_script "always"
    run loop "always"

define inline_script inline_script
    set _prepare ""
    ___run__
    # Import the widgets library
    from libopensesame import widgets

    option1 = self.get('choice1')
    option2 = self.get('choice2')

    # Create a form (margins order: top,right,bottom,left)
    form = widgets.form(self.experiment, cols=[1,1,1,1], rows=[6,1,1,1,1,1,1], margins=(10,10,10,10), spacing=10)

    # Create widgets
    checkbox1 = widgets.checkbox(form, text=option1, group='group', var='my_response_var_2')
    checkbox2 = widgets.checkbox(form, text=option2, group='group', var='my_response_var_2')
    nextbutton = widgets.button(form, text='Next', center=True, var='next_button_clicked')

    # Add the widgets to the form. The position in the form is indicated as a (column, row) tuple.
    form.set_widget(checkbox1, (1,2),colspan=2)
    form.set_widget(checkbox2, (1,3),colspan=2)
    form.set_widget(nextbutton, (0,6),colspan=4)

    # Display the form
    form.render()

    # Evaluate the form
    form._exec()
    __end__

define logger logger

define loop loop
    set break_if "never"
    set column_order "choice1;choice2"
    set cycles "2"
    set item "sequence"
    set order "sequential"
    set repeat "1"
    set skip "0"
    setcycle 0 choice1 "text1"
    setcycle 0 choice2 "text2"
    setcycle 1 choice1 "text3"
    setcycle 1 choice2 "text4"
    run sequence

define sequence sequence
    run _loop "always"
    run logger "always"

Could you indicate to me where I am going wrong?

Thank you,
Johannes

eduard · April 2015

Hi Johannes,

I can't tell you why your script isn't working, because OpenSesame doesn't allow me to import it for some strange reasons, but I suspect the reason could be related to the prepare-run phases. In any way, here is a small example of a script that should do what you want it to.
Let us know, if there are other problems.

Eduard

absurd · April 2015

Hi Eduard,

Thank you for providing this example script. My misunderstanding was that I tried to solve the problem by using nested loops.

I now tried out your example script and I have some questions. So what happens is the following:

I start the script and if I do not select a checkbox it processes a second loop which is essentially a copy of the first but with a warning message and a break if condition. I guess you have added the second, different row in the second loop to make the processing just more visible?

However, if I do not select anything, the experiment ends after 3 cycles. That's because the second is repeated 3 times. That would be bad in a real experiment, as the first loop would just not be processed anymore, no matter if there are still lines in it.

Thus, my questions are:

1) To be totally sure that a participant cannot accidentally end the experiment I would need to set the repeat value of the second loop to a very high number?

2) I initially thought that internally/behind the GUI of OS the break if condition would turn the for loop of a loop item into a while loop. But this does not seem to be the case. But with a while loop I could achieve an potentially endless processing until a break condition is met, couldn't I? Is this possible via the GUI only?

3) If my first loop item has 20 lines from which OS chooses randomly, how can I make sure that OS chooses the same line in the second loop that was chosen in the first loop and repeats only this line and does not go on with the next line in the second loop?

Best,
Johannes

Update

Thanks to Eduards comment in another thread I managed to get a working solution by using a python inline script.

I just used a separate form.render() followed by a final form.exec() call. I enclosed the form.render() in a while True: loop with a break if condition that is met only when the checkbox response variable was !='no'. That did the trick.

However, I am still unsure if this would be also possible using the GUI and I'd like to know what the break if in the advanced loop options is doing behind the scenes.

Johannes

eduard · April 2015

Hi Johannes,

Nice to hear that it works now. But just for sakes of completeness here the things that I know:

I guess you have added the second, different row in the second loop to make the processing just more visible?

Yes. I haven't work much with forms yet. So, I just copied your code a bit to check things out.

1) To be totally sure that a participant cannot accidentally end the experiment I would need to set the repeat value of the second loop to a very high number?

Right. I chose a value of three, just to test the script and don't have to repeat it forever

2) But with a while loop I could achieve an potentially endless processing until a break condition is met, couldn't I? Is this possible via the GUI only?

I'm not super sure, but I think there is no while loop possible with the GUI loop items. Every time when other users had similar problems, for which while loops were a solution, Sebastiaan's suggestion was to use an absurdly high value of repeats that creates virtually a while loop. I suppose @Sebastiaan, can tell you more about this matter, if wished.

how can I make sure that OS chooses the same line in the second loop that was chosen in the first loop and repeats only this line

I haven't tried it myself, but I think you could create the second loop in a way, that it doesn't provide any new information to the form. What I mean is that the all information that you need to built the form (e.g. your 'text1' variable, if I remember right), are not provided by the second loop, but passed on from earlier in the experiment, i.e. the first loop and its elements. So basically, the second loop is in a sense empty and merely a wrapper around your form. Do you understand, what I am trying to explain?

I hope this cleared things up.

Eduard

mati · February 2018

Hey there, I am facing the same challenge Johannis did about 2 years ago. I have a form item where participants use a rating scale to evaluate a stimulus. I would like that participants are only able to proceed once they have provided an answer. If the "next" button is pressed without filling in the rating scale, I would like the same stimulus to be repeated, with the note "Please provide an answer" (as mentioned above).
By now the link eduard provided to a small script with a solution is dead, and without it it is too difficult for me to understand this thread. Could you repload the sample script somewhere?

sebastiaan · February 2018

Hi Mati,

OpenSesame 3.2 allows you to validate form input, so the solution posted above is no longer necessary. See here:

http://osdoc.cogsci.nl/3.2/manual/forms/validation/

Cheers!
Sebastiaan

Sabrina · December 2018

Hi there,
I need also help with the validation. The Information in the link helps to validate my form base, when there are only checkboxes inside. But I have also rating scales and when I use the validation for this form base it puts checkmarks in the rating-scale and I don't know what to change in the inline script to solve this problem. The second problem is, that I want that my subjects can press the next button when they answered the rating scale with yes but when they answered it with no they have to fill in a word in a text-input and only then they should be able to proceed. In this case the question is not, if they have answered the rating scale, rather if they answered with yes they can go on to the next page, but if not they have to fill in the text input and only if this is answered they should go on. I Have read a lot of the posts here but I can't find the right solution. Until now I have added an inline script so that they have to answer the rating scale and then they can proceed but that's not what I want. Is there anyone who
can help to fix this problem? I think I need some more if statements in the while loop, but I don't know how to build them.

Thanks in advance

Sabrina

sebastiaan · December 2018

Hi Sabrina,

The Information in the link helps to validate my form base, when there are only checkboxes inside.

Just to avoid confusion: form validation does not work with a form_base item. It requires Python scripting (i.e. an inline_script item), as also shown in the documentation. Are you sure you're not trying to paste Python code into the script of a form_base item? (Which won't work.)

But I have also rating scales and when I use the validation for this form base it puts checkmarks in the rating-scale and I don't know what to change in the inline script to solve this problem.

This isn't entirely clear to me. Perhaps you can upload your experiment to illustrate the issue?

The second problem is, that I want that my subjects can press the next button when they answered the rating scale with yes but when they answered it with no they have to fill in a word in a text-input and only then they should be able to proceed. In this case the question is not, if they have answered the rating scale, rather if they answered with yes they can go on to the next page, but if not they have to fill in the text input and only if this is answered they should go on.

In that case, you'll need a slightly more complicated check in the form validation function (my_form_validator()). You can see how this could work below, with comments explaining the logic.

def my_form_validator():

    # Yes is the first option, so coded with 0
    if var.yesno_response == 0:
        return True
    # No is the second option, so coded with 1. If the participant
    # answers no, then the text response cannot be empty
    if var.yesno_response == 1 and var.text_response != u'':
        return True
    # If none of the above is true, then we decline the form
    return False


yesno_widget = RatingScale(nodes=[u'yes', u'no'], var=u'yesno_response')
text_widget = TextInput(stub=u'Why not?', var=u'text_response')
button_widget = Button(text=u'Ok')
my_form = Form(validator=my_form_validator, rows=[1,1,1], cols=[1])
my_form.set_widget(yesno_widget, (0, 0))
my_form.set_widget(text_widget, (1, 0))
my_form.set_widget(button_widget, (2, 0))
my_form._exec()

Cheers!
Sebastiaan

Sabrina · January 2019

Hi Sebastiaan,

thanks for your reply and sorry for the confusion betwenn form_base and form_validator.
This results because I want to fix the Problem that I discribed above first with a form_base and an inline_script_item, which includes a script from Lotje that checks if the rating scale is answered and if not then it shows a warning message. This works quit good, but not for the text_input. And because of that I don't know what syntax is needed in the inline_script_item to fix it I want to try it with form_validator.

I ad your syntax into my form_validator and it works as it should, but not for the first rating_scale. I'm not able to set a checkmark, may be I forgot something or it is because of the diffrent defaults (checkbox=no and rating_scale=none).
Here it is:

def AGG():

    if var.Gebland1 == 0:
        return True

    if var.Gebland1 == 1 and var.Gebland2 != u'':
        return True 
    return False

    return var.Alter != u'' and var.Geschlecht != u'none' 


def filter_digits(ch):

    return ch in u'789101112'

f = Form(rows=[1,1,1,1,1,1,1], cols=[1,1], spacing=10, margins=(20,20,20,20), validator=AGG)
f.set_widget(Label(text='Bitte beantworte die folgenden Fragen.',center=True), (0, 0), colspan=2)
f.set_widget(Label(text='Bist du ein Mädchen oder ein Junge?',center=False), (0, 1), colspan=2)
rating_scale = RatingScale(
    nodes=[u'Mädchen', u'Junge'], var=u'Geschlecht')
f.set_widget(rating_scale, (1, 1))
f.set_widget(Label(text='Wie alt bist du?',center=False), (0, 2))
text_input = TextInput(
        text=u'', frame=True, center=False, stub=u'',
        return_accepts=True, var=u'Alter', key_filter=filter_digits)
f.set_widget(text_input, (1, 2))
f.set_widget(Label(text='Wurdest du in Deutschland geboren?',center=False), (0, 3))
rating_scale = RatingScale(
    nodes=[u'Ja', u'Nein'], click_accepts=False,
    orientation=u'horizontal', var=u'Gebland1', default=None)
f.set_widget(rating_scale, (1, 3))
f.set_widget(Label(text='Wenn "Nein", dann gib bitte im Kästchen rechts ein, in welchem Land du geboren wurdest.',center=False), (0, 4))
text_input = TextInput(
        text=u'', frame=True, center=False, stub=u'',
        return_accepts=True, var=u'Gebland2')
f.set_widget(text_input, (1, 4))
f.set_widget(Button(text='Weiter'), (0, 6), colspan=2)
f._exec()

Is it also possible to add in this script a warning message. Because the questionnaire is for childrens and I don't know if they understand what to do when the form stays open until a response is given.

Or is it better to use the first way with the form_base and the inline_script Item, but which syntax should I use to solve the problem for what you wrote me the syntax for the form validator.
I hope I'm not confusing you again.

My second question is if I can use this answer of the rating-scale to split my experiment in two sequences. In that way that if they answered the rating_scale with yes then the subjects get sequence A (for example questionnaire A with 20 Items) and if they answered with no they get sequence B.
May be I can use the syntax from this discussion am I right?
https://forum.cogsci.nl/.../set-a-different-path-in-the-experiment-depending- on-the-multiple-choice-response

Now realy this is my last question. Can I change the color of the background and the foreground in the form_validator like in a formbase "set background". The first sequence in my experiment is an IAT and the second sequence is a questionnaire. The IAT backround is black and the questionnaire background should be white. Is this possible?

I'm so sorry for the many question but I'm very thankfull for your help.

Greetings Sabrina smile:

eduard · January 2019

Hi Sabrina,

This part of your code:

def AGG():

    if var.Gebland1 == 0:
        return True

    if var.Gebland1 == 1 and var.Gebland2 != u'':
        return True 
    return False

    return var.Alter != u'' and var.Geschlecht != u'none'

is probably part of the problem. The last line (return var.Alter....) will never be executing, because the previous line (return False), will always terminate the function (if it hasn't been already terminated). So, what you want is probably this:

def AGG():

    if var.Gebland1 == 0:
        return True

    if var.Gebland1 == 1 and var.Gebland2 != u'':
        return True 

    if var.Alter != u'' and var.Geschlecht != u'none' : 
        return True
    return False

In general, the form validator should never return anything else than True of False.

My second question is if I can use this answer of the rating-scale to split my experiment in two sequences

You can use the run-if field to decide which items to run. I attach an example experiment that implements this. Let me know if you don't understand how it works.

Can I change the color of the background and the foreground in the form_validator like in a formbase "set background".

As far as I can see you can't change the background of a form directly, but it can be adapted by passing an item to the item keyword because the form takes the foreground and background color of that item. Unfortunately, I don't really know what exactly a valid item would be that you could pass to the form. Maybe @sebastiaan can help out?

Eduard

sebastiaan · January 2019

As far as I can see you can't change the background of a form directly

The easiest way to do it is to simply change the background variable before the form, and then (if necessary) reset it right after. Like so:

var.background = 'red'  # Set new background for form
form = Form()
button = Button(text=u'Click me!', frame=True, center=True, var=u'response')
form.set_widget(button, (0, 0))
form._exec()
var.background = 'black'  # Restore old background

Sabrina · January 2019

Hi together,
with your help it was possible to change the color and to split my experiment into two sequences.
But the problem that the first rating_scale ist not clickable is still the same (the gender_rating_scale above). I have changed the rating_scale into two checkboxes. And also with the checkboxes it is the same. Particularly when the checkbox (1,1) is in the same row with the question (0,1). I don't understand this. I put the checkboxes in the row below the question and then it is working.

Is it possible to add in the form validator a warning message or is this only possible with an form_base_item and an added inline_script_item including a while loop?

Thanks a lot again

Sabrina

sebastiaan · January 2019

Edited to fix validation script

But the problem that the first rating_scale ist not clickable is still the same (the gender_rating_scale above). I have changed the rating_scale into two checkboxes. And also with the checkboxes it is the same. Particularly when the checkbox (1,1) is in the same row with the question (0,1). I don't understand this. I put the checkboxes in the row below the question and then it is working.

The problem is that the widgets in your form overlap. Notably, you've set the colspan of the Label widgets on the left to 2. That means that they also cover the right column, thus covering the RatingScale that sits underneath. Does that make sense?

Is it possible to add in the form validator a warning message or is this only possible with an form_base_item and an added inline_script_item including a while loop?

That's possible. In the validation function (here my_form_validator()) you can simply create a Canvas with some warning message and show it. Then you also want to re-show the original form canvas to avoid visual artifacts. I adapted the example from the documentation below. You can try to figure out how to apply this to your own code!

def my_form_validator():

    """Checks whether both the gender and age fields have been filled out"""

    if var.gender != u'no' and var.age != u'':
        return True
    # Show warning message
    c = Canvas()
    c += Text('Please enter a gender and an age!')
    c.show()
    # Wait for it ...
    clock.sleep (1000)
    # Show original canvas (assuming that the form is called my_form)
    my_form.canvas.show()
    return False


def filter_digits(ch):

    """Allows only digit characters as input"""

    return ch in u'0123456789'


# Define all widgets
button_ok = Button(text=u'Ok')
label_gender= Label(u'Your gender')
checkbox_male = Checkbox(text=u'Male', group=u'gender', var=u'gender')
checkbox_female = Checkbox(text=u'Female', group=u'gender', var=u'gender')
label_age = Label(u'Your age')
# Specify a key filter so that only digits are accepted as text input
input_age = TextInput(stub=u'Age here …', var=u'age', key_filter=filter_digits)
# Build the form. Specify a validator function to make sure that the form is
# completed.
my_form = Form(validator=my_form_validator, rows=[1,1,1], cols=[1,1,1])
my_form.set_widget(label_gender, (0, 0))
my_form.set_widget(checkbox_male, (1, 0))
my_form.set_widget(checkbox_female, (2, 0))
my_form.set_widget(label_age, (0, 1))
my_form.set_widget(input_age, (1, 1), colspan=2)
my_form.set_widget(button_ok, (1, 2))
my_form._exec()

But the problem that the first rating_scale ist not clickable is still the same (the gender_rating_scale above). I have changed the rating_scale into two checkboxes. And also with the checkboxes it is the same. Particularly when the checkbox (1,1) is in the same row with the question (0,1). I don't understand this. I put the checkboxes in the row below the question and then it is working.

The problem is that the widgets in your form overlap. Notably, you've set the colspan of the Label widgets on the left to 2. That means that they also cover the right column, thus covering the RatingScale that sits underneath. Does that make sense?

Sabrina · January 2019

Hi Sabastiaan,

when I use your syntax (I should use the second one with clock.sleep (1000) right?) then is the warning message also shortly shown when I answered the Checkboxes and the text-input and also I cant press the next button because it is going to the next page by it self. Am I doing something wrong?
I have said that I changed to the validator, but before I used a form base and an inlinscript from Lotje with a while loop, that shows the warning mesaage and when it goes back to the form the answeres which habe been clickt are still there. When the subjects fill out the answer they have forgotten they can go on. Is this able to combine this with the syntax you wrote?

here is while loop which I used before.

while True:
# Make a variable storing whether the form is completely filled
# in on or not. The starting value is False. If one of the
# 'checks' below is not met, its set to True:
incomplete = False

    # Execute the form item:
exp.items["AGG"].run()

    # Check whether your criteria are met:

    # The easiests way to do that here is to see whether none of your response 
    # variables are set to 'None'. 'None' indicates that no box was ticked, whereas
    # any other variable indicates that the question was not left unanswered.
    # That's all you need to know, right?

if None in [var.Geschlecht, var.Alter, var.Gebland1]:  => do have to use 'no' when it is a CB?
        incomplete = True

    # If incomplete is still False, break out of this while loop
    # and continue with the experiment.
if not incomplete:
    break

    # If the form turns out to be incomplete, show a warning.
else:
    items.execute("Warnung")

        # Next, the form_base will be executed again.
        # This continues as long as the form is incomplete.

Thank you so much for your help

Sabrina

Sabrina · January 2019

Hi together,

in the last time my experiment crashes very often and don't runs until the end. Under the point Details is standing: items stack:?`` and Python seems to have crashed. This should not happen. If Python crashes often, please report it on the OpenSesame forum.
Do you know what to do to solve this?
Thanks Sabrina

sebastiaan · January 2019

Hi Sabrina,

That's unfortunate. This error means that the Python interpreter itself crashed, which is never due to a bug in the experiment. (I.e. it's not something that you do wrong. It's a problem with Python or one of the underlying libraries.)

If you find that the experiment consistently crashes at the same moment, then you can see if there's something you can change to work around it. Is the crash consistent?

If not, then your best bet is to switch to a different version of OpenSesame, for example the version based on Python 3. These crashes are generally specific to a system in combination with some version of Python, so simply changing either of those sometimes makes the problem go away.

Cheers!
Sebastiaan

Sabrina · January 2019

Hi Sebastiaan,

yes the crash is mostly consistent. I have an IAT sequence (it is a template) and at the same level I add a questionniare sequence (could this be the problem?). The IAT is runing, but the questioniare sequence crashes very often. This questionaire exists of two diffrent sequences one with about
20 items an the other with 22 items.

Sabrina · January 2019

Hi Sebastiaan,
can you tell me what I'm doing wrong with your syntax (warning message). I used this part right?

    # Show warning message
    c = Canvas()
    c += Text('Please enter a gender and an age!')
    c.show()
    # Wait for it ...
    clock.sleep (1000)
    # Show original canvas (assuming that the form is called my_form)
    my_form.canvas.show()
    return var.gender != u'no' and var.age != u''

But the warning message is also shortly shown when all checkboxes, text inputs etc. have been filled out and then it goes on by it self, so that the next-button could not be clicked. I tried out to put the syntax wihtout the clock.sleep in the prepare phase ant the other one in the run phase but it is not working.

Thanks for your help

Sabrina

sebastiaan · January 2019

Hi Sabrina,

But the warning message is also shortly shown when all checkboxes, text inputs etc. have been filled out and then it goes on by it self, so that the next-button could not be clicked

Right, I made an odd mistake in the validation function, because it always showed the warning message, even when the validation passed. To fix this, you have to first check whether the form is ok, if so return True right away, if not show the Canvas and return False. Do you see the logic below?

def my_form_validator():

    """Checks whether both the gender and age fields have been filled out"""

    if var.gender != u'no' and var.age != u'':
        return True
    # Show warning message
    c = Canvas()
    c += Text('Please enter a gender and an age!')
    c.show()
    # Wait for it ...
    clock.sleep (1000)
    # Show original canvas (assuming that the form is called my_form)
    my_form.canvas.show()
    return False

yes the crash is mostly consistent. I have an IAT sequence (it is a template) and at the same level I add a questionniare sequence (could this be the problem?).

What happens if you run the questionnaire as a separate experiment? Does splitting the experiment up this way make the error go away? These Python crashes are hard to debug, because they don't have a clear cause (or error message). So it's in part a matter of trial and error to see when they do and when they do not occur.

Cheers,
Sebastiaan

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[solved] Custom forms: How to activate a 'Next Button' only when a checkbox is chosen

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[solved] Custom forms: How to activate a 'Next Button' only when a checkbox is chosen

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