Wizard Form

Library that helps to create wizard form with android databinding eliminating boiler plate code.

This library was built on top of binding-collection-adapter

Contents

• Installation
• Important classes
• Tutorial
• Bugs and feedback
• Credits

Installation

compile 'br.com.leandroferreira:wizard-form:[lastestVersion]'

Important classes

WizardPager

Implementation of the ViewPager specialised for wizard forms.

Navigator

Navigator must implement Navigator interface. This class is responsible to coordinate the navigation of the pages.

StateHolder

StateHolder is the class used to hold the state of the from. You need to insert the POJO that you want to track.

WizardPageViewModel/ UpdatableWizardPageViewModel

All the fragments ViewModel of fragments of WizardPager must implement WizardPageViewModel or UpdatableWizardPageViewModel.

Tutorial

1 - Add the XML of the WizardPager

<br.com.leandroferreira.wizard_form.views.NonSwipeableWizardPager
      android:id="@+id/viewPager"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:itemBinding="@{viewModel.itemBinding}"
      app:items="@{viewModel.pages}"
      app:navigator="@{viewModel.navigator}"
      app:stateHolder="@{viewModel.stateHolder}"
      />

2 - Create a navigator:

class ViewPagerNavigator : Navigator {
    override fun nextPage() {
        if (viewPager.currentItem < viewPager.adapter.count) {
           viewPager.currentItem = viewPager.currentItem + 1
        }
    }

    override fun previousPage() {
        if (viewPager.currentItem > 0) {
            viewPager.currentItem = viewPager.currentItem - 1
        }
    }

   override fun navigateToPage(page: Int) {
         viewPager.currentItem = page
    }

    override fun cancelNavigation() {
        finish()
    }

    override fun currentPage(): Int = viewPager.currentItem
}

3 - Define a DTO (data transfer object) to be used in the StateHolder. Example:

data class User(var name: String?, var lastName : String?, var age : String?)

4 - Create a StateHolder, that is going to be inserted in the WizardPager/UpdatableWizardPager

val stateHolder = StateHolder<User>(User("", "", ""))

5 - Define all your pages and implement UpdatableWizardPageViewModel or WizardPageViewModel. Example:

class PageFourViewModel : UpdatableWizardPageViewModel<User>() {

val name = ObservableField<String?>()
val lastName = ObservableField<String?>()
val age = ObservableField<String?>()

init {
    name.set(stateHolder?.stateDto?.name)
    lastName.set(stateHolder?.stateDto?.lastName)
    age.set(stateHolder?.stateDto?.age)
}

override fun getOnStateChangeListener(): OnStateChangeListener<User> =
        object : OnStateChangeListener<User> {
            override fun getState(stateDto: User) {
                name.set(stateDto.name)
                lastName.set(stateDto.lastName)
                age.set(stateDto.age)
            }
        }
}

6 - Bind your dependencies just like you would with binding-collection-adapter . Example of viewModel:

class MainViewModel(val navigator: Navigator) {
   val itemBinding:     OnItemBind<WizardPageViewModel<User>>
    get() = OnItemBind { itemBinding1, position, _ ->
            when (position) {
               0 -> itemBinding1.set(BR.viewModel, R.layout.page1_view)
               1 -> itemBinding1.set(BR.viewModel, R.layout.page2_view)
               2 -> itemBinding1.set(BR.viewModel, R.layout.page3_view)
               3 -> itemBinding1.set(BR.viewModel, R.layout.page4_view)
               else -> throw IllegalArgumentException("There is more viewModel than views!")

           }
        }

    val pages = ObservableArrayList<WizardPageViewModel<User>>()
    val stateHolder = StateHolder<User>(User("", "", ""))

     init {
        pages.add(PageOneViewModel())
        pages.add(PageTwoViewModel())
        pages.add(PageThreeViewModel())
        pages.add(PageFourViewModel())
     }
}

For a complete example, you can check this repository for an example of the app shown in the gif above

Bugs and Feedback

For bugs, feature requests, and discussion please use GitHub Issues.

Credits

This library was built on top of binding-collection-adapter

And that's it! Enjoy!