Implement the entryMode extension

[aurangzaibumer]

IMPORTANT: All PRs must be linked to an issue (except for extremely trivial and straightforward changes).

Issue# 1272

Description
Clear and concise code change description.

Alternative(s) considered
Have you considered any alternatives? And if so, why have you chosen the approach in this PR?

Type
Choose one: Feature

Screenshots/Video

issue_1272.mp4

Checklist

• I have read and acknowledged the Code of conduct.
• I have read the Contributing page.
• I have signed the Google Individual CLA, or I am covered by my company's Corporate CLA.
• I have discussed my proposed solution with code owners in the linked issue(s) and we have agreed upon the general approach.
• I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the style guide of this project.
• I have run ./gradlew check and ./gradlew connectedCheck to test my changes locally.
• I have built and run the demo app(s) to verify my change fixes the issue and/or does not break the demo app(s).

[joiskash]

Oh there is some weird bug that shows overlapped questions 0:44. Is there any reproducibility ? We will have to create an issue regarding this. But otherwise, looks great!

cc: @jingtang10

[aurangzaibumer]

@dubdabasoduba as per discussion on standup, there is a PR for submit button #1215 this needs to be merged first in order to work on the submit button so probably we can create a separate ticket for submit button implementation so this can be merged if reviewed.

[joiskash]

Thinking about this a little more, I figured that this more than just validation.. This is triggering some logic on page change events within the QuestionnaireFragment. So we could refactor as such. This will allow more complex use cases such as :

1. Not allowing to switch page until a minimum amount of time has passed
2. Not allowing page change if the answers are exactly the same as the previous questionnaire answered . (this can happen in cases were there is a monetary incentive to complete forms)

Validation of all the items on the page can be the default implementation provided by the library. Developers can choose to add this in their Strategies too.

By having a context, the main point is that the strategy can be changed during run time. So a developer can do something like

dataConfig.questionnairePageEventContext.setStrategy(newStrategy)

at any point in the code during run time.

Create a context class that will be stored in the DataCapture Config

class QuestionnairePageChangeEventContext{
  private var pageChangeStrategy : PageChangeStrategy = DefaultStrategy()

  fun setStrategy(pageChangeStrategy : PageChangeStrategy ){
      this.pageChangeStrategy = pageChangeStrategy
  }
  
  //This function will be called in the QuestionnaireViewModel goToNextPage and if returns true  then pageFlow.value will be changed.

  fun triggerPageNextEvent( list: List<QuestionnaireItemViewItem> ):Boolean{
  return pageChangeStrategy.shouldGoToNextPage(list)
  }

  //This function will be called in the QuestionnaireViewModel goToPreviousPage and if returns true  then pageFlow.value will be changed.

  fun triggerPreviousEvent( list: List<QuestionnaireItemViewItem> ):Boolean{
  return pageChangeStrategy.shouldGoToPreviousPage(list)
  }
}

The strategy interface will be like this.

interface PageChangeStrategy {

  fun shouldGoToPreviousPage(list: List<QuestionnaireItemViewItem>): Boolean

  fun shouldGoToNextPage(list: List<QuestionnaireItemViewItem>): Boolean

}

The default implementation can be like :

class DefaultPageChangeStrategy: PageChangeStrategy{

  override fun shouldGoToPreviousPage(list: List<QuestionnaireItemViewItem>): Boolean{
    return list.any { it.isErrorTriggered }
  }

  override fun shouldGoToNextPage(list: List<QuestionnaireItemViewItem>): Boolean
    return list.any { it.isErrorTriggered }
  }

and finally the change in the viewmodel can be as such:

internal class QuestionnaireViewModel(application: Application, state: SavedStateHandle) :{
  private val questionnairePageEventContext by lazy {
    DataCapture.getConfiguration(getApplication()).questionnairePageEventContext // declare and initialize this in the DataConfig. It should never be null
  }
.
.
.
  internal fun goToPreviousPage() {
    if (questionnairePageEventContext.triggerPagePreviousEvent()){
              pageFlow.value = pageFlow.value!!.previousPage()
     }
  }
  
  internal fun goToNextPage() {
    if (questionnairePageEventContext.triggerPageNextEvent()){
              pageFlow.value = pageFlow.value!!.nextPage()
     }
  }
}

Some one from google can comment on this, @jingtang @kevinmost

[codecov]

Codecov Report

Merging #1301 (3e70103) into master (61c383e) will not change coverage.
The diff coverage is n/a.

❗ Current head 3e70103 differs from pull request most recent head 35b7774. Consider uploading reports for the commit 35b7774 to get more accurate results

@@      Coverage Diff       @@
##   master   #1301   +/-   ##
==============================
==============================

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[aurangzaibumer]

Thinking about this a little more, I figured that this more than just validation.. This is triggering some logic on page change events within the QuestionnaireFragment. So we could refactor as such. This will allow more complex use cases such as :

1. Not allowing to switch page until a minimum amount of time has passed
2. Not allowing page change if the answers are exactly the same as the previous questionnaire answered . (this can happen in cases were there is a monetary incentive to complete forms)

Validation of all the items on the page can be the default implementation provided by the library. Developers can choose to add this in their Strategies too.

By having a context, the main point is that the strategy can be changed during run time. So a developer can do something like

dataConfig.questionnairePageEventContext.setStrategy(newStrategy)

at any point in the code during run time.

Create a context class that will be stored in the DataCapture Config

class QuestionnairePageChangeEventContext{
  private var pageChangeStrategy : PageChangeStrategy 

  fun setStrategy(pageChangeStrategy : PageChangeStrategy ){
      this.pageChangeStrategy = pageChangeStrategy
  }
  
  //This function will be called in the QuestionnaireViewModel goToNextPage and if returns true  then pageFlow.value will be changed.

  fun pageNextEvent( list: List<QuestionnaireItemViewItem> ):Boolean{
  return pageChangeStrategy.shouldGoToNextPage(list)
  }

  //This function will be called in the QuestionnaireViewModel goToPreviousPage and if returns true  then pageFlow.value will be changed.

  fun pagePreviousEvent( list: List<QuestionnaireItemViewItem> ):Boolean{
  return pageChangeStrategy.shouldGoToPreviousPage(list)
  }
}

The strategy interface will be like this.

interface PageChangeStrategy {

  fun shouldGoToPreviousPage(list: List<QuestionnaireItemViewItem>): Boolean

  fun shouldGoToNextPage(list: List<QuestionnaireItemViewItem>): Boolean

}

The default implementation can be like :

class DefaultPageChangeStrategy: PageChangeStrategy{

  override fun shouldGoToPreviousPage(list: List<QuestionnaireItemViewItem>): Boolean{
    return list.any { it.isErrorTriggered }
  }

  override fun shouldGoToNextPage(list: List<QuestionnaireItemViewItem>): Boolean
    return list.any { it.isErrorTriggered }
  }

and finally the change in the viewmodel can be as such:

internal class QuestionnaireViewModel(application: Application, state: SavedStateHandle) :{
  private val questionnairePageEventContext by lazy {
    DataCapture.getConfiguration(getApplication()).questionnairePageEventContext // declare and initialize this in the DataConfig. It should never be null
  }
.
.
.
  internal fun goToPreviousPage() {
    if (questionnairePageEventContext.pagePreviousEvent()){
              pageFlow.value = pageFlow.value!!.previousPage()
     }
  }
  
  internal fun goToNextPage() {
    if (questionnairePageEventContext.pageNextEvent()){
              pageFlow.value = pageFlow.value!!.nextPage()
     }
  }
}

Some one from google can comment on this, @jingtang @kevinmost

feedback implemented, please review @joiskash . Thanks

[joiskash]

Great work, left a few comments. I request someone from google and Ona to review this before you write the UTs. @jingtang10 @f-odhiambo

[jingtang10]

@santosh-pingle can you leave some comments please

[aurangzaibumer]

Great work, left a few comments. I request someone from google and Ona to review this before you write the UTs. @jingtang10 @f-odhiambo

cc @dubdabasoduba

[santosh-pingle]

@santosh-pingle can you leave some comments please

sure.

[aurangzaibumer]

@jingtang10 can you please review on your availability. thanks

addressed

[santosh-pingle]

@aurangzaibumer can you please add some questionnaire examples?

[aurangzaibumer]

@aurangzaibumer can you please add some questionnaire examples?

"extension": [ 
    {
      "url" : "http:https://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-entryMode",
      "valueCode" : "prior-edit"
    } 
 ]

for more entry-mode codes : http:https://build.fhir.org/ig/HL7/sdc/ValueSet-entryMode.html