Update MVP-Fragment sample to be closer to actual MVP pattern

Zhuinden · Sep 2, 2018 · 725107ec9ac60848a1c4560a988a3b18a6b5fd66 · 725107e
1 parent 9972289
commit 725107ec9ac60848a1c4560a988a3b18a6b5fd66
diff --git a/...ts/src/main/java/com/zhuinden/simplestackdemoexamplefragments/application/MainActivity.kt b/...ts/src/main/java/com/zhuinden/simplestackdemoexamplefragments/application/MainActivity.kt
@@ -39,21 +39,39 @@ class MainActivity : AppCompatActivity(), StateChanger {

        super.onCreate(savedInstanceState)

+        // this must be after `super.onCreate` otherwise multiple of them would exist after process death
        supportFragmentManager.findFragmentByTag("MAIN_SCOPE_LISTENER").also { mainScopeListener ->
            if (mainScopeListener == null) {
                supportFragmentManager.beginTransaction().add(MainScopeListener(), "MAIN_SCOPE_LISTENER").commit()
+                supportFragmentManager.executePendingTransactions() // this guarantees that the retained fragment exists by the time the Repository needs it.
            }
        }

        setContentView(R.layout.activity_main)

        this.fragmentStateChanger = FragmentStateChanger(supportFragmentManager, R.id.root)
        mainView.onCreate()
+
+        backstackDelegate.setStateChanger(this)
+        /*
+         * IMPORTANT!
+         *
+         * The order of lifecycle after process death is the following:
+         * - Activity onCreate
+         * - Activity.onStart
+         * - Fragment.onActivityCreated
+         * - Fragment.onCreateView
+         * - Fragment.onViewCreated
+         * - Activity.onPostCreate
+         *
+         * Therefore if ScopedServices is used with Fragments, the scopes must be built in onCreate,
+         * meaning the StateChanger must be set in onCreate, and onPostCreate runs too late,
+         * otherwise the scopes won't exist in onViewCreated after process death.
+         */
    }

    override fun onPostCreate(savedInstanceState: Bundle?) {
        super.onPostCreate(savedInstanceState)
-        backstackDelegate.setStateChanger(this)
        mainView.onPostCreate()
    }

@@ -76,6 +94,7 @@ class MainActivity : AppCompatActivity(), StateChanger {

    override fun getSystemService(name: String): Any? = when {
        TAG == name -> this
+        BACKSTACK_DELEGATE_TAG == name -> backstackDelegate
        else -> super.getSystemService(name)
    }

@@ -93,11 +112,16 @@ class MainActivity : AppCompatActivity(), StateChanger {
    }

    companion object {
-        const val TAG = "MainActivity"
+        private const val BACKSTACK_DELEGATE_TAG = "BackstackDelegate"

        @SuppressLint("WrongConstant")
-        operator fun get(context: Context): MainActivity {
-            return context.getSystemService(TAG) as MainActivity
-        }
+        operator fun get(context: Context): MainActivity =
+            context.getSystemService(TAG) as MainActivity
+
+        @SuppressLint("WrongConstant")
+        fun getBackstackDelegate(context: Context): BackstackDelegate =
+            context.getSystemService(BACKSTACK_DELEGATE_TAG) as BackstackDelegate
+
+        const val TAG = "MainActivity"
    }
 }
diff --git a/...simplestackdemoexamplefragments/presentation/paths/addoredittask/AddOrEditTaskFragment.kt b/...simplestackdemoexamplefragments/presentation/paths/addoredittask/AddOrEditTaskFragment.kt
@@ -4,8 +4,9 @@ import android.app.Activity
 import android.os.Bundle
 import android.view.View
 import android.view.inputmethod.InputMethodManager
-import com.zhuinden.simplestackdemoexamplefragments.application.Injector
 import com.zhuinden.simplestackdemoexamplefragments.util.BaseFragment
+import com.zhuinden.simplestackdemoexamplefragments.util.MvpPresenter
+import com.zhuinden.simplestackdemoexamplefragments.util.backstackDelegate
 import kotlinx.android.synthetic.main.path_addoredittask.*
 import org.jetbrains.anko.sdk15.listeners.textChangedListener

@@ -14,10 +15,22 @@ import org.jetbrains.anko.sdk15.listeners.textChangedListener
 */

 // UNSCOPED!
-class AddOrEditTaskFragment : BaseFragment<AddOrEditTaskPresenter.ViewContract, AddOrEditTaskPresenter>(), AddOrEditTaskPresenter.ViewContract {
-    private val addOrEditTaskPresenter = Injector.get().addOrEditTaskPresenter()
+class AddOrEditTaskFragment : BaseFragment<AddOrEditTaskFragment, AddOrEditTaskFragment.Presenter>() {
+    companion object {
+        const val CONTROLLER_TAG = "AddOrEditTaskPresenter"
+    }
+
+    interface Presenter: MvpPresenter<AddOrEditTaskFragment> {
+        fun onTitleChanged(title: String)
+
+        fun onDescriptionChanged(description: String)

-    override val presenter: AddOrEditTaskPresenter = addOrEditTaskPresenter
+        fun onSaveButtonClicked()
+    }
+    
+    override val presenter: Presenter by lazy {
+        backstackDelegate.lookupService<AddOrEditTaskFragment.Presenter>(CONTROLLER_TAG)
+    }

    override fun getThis(): AddOrEditTaskFragment = this

@@ -26,37 +39,35 @@ class AddOrEditTaskFragment : BaseFragment<AddOrEditTaskPresenter.ViewContract,

        textAddTaskTitle.textChangedListener {
            afterTextChanged { editable ->
-                addOrEditTaskPresenter.updateTitle(editable.toString())
+                presenter.onTitleChanged(editable.toString())
            }
        }

        textAddTaskDescription.textChangedListener {
            afterTextChanged { editable ->
-                addOrEditTaskPresenter.updateDescription(editable.toString())
+                presenter.onDescriptionChanged(editable.toString())
            }
        }
    }

-    fun saveTask() = addOrEditTaskPresenter.saveTask()
-
-    fun navigateBack() {
-        addOrEditTaskPresenter.navigateBack()
-    }
-
-    override fun setTitle(title: String) {
+    fun setTitle(title: String) {
        textAddTaskTitle.setText(title)
    }

-    override fun setDescription(description: String) {
+    fun setDescription(description: String) {
        textAddTaskDescription.setText(description)
    }

-    override fun hideKeyboard() {
+    fun hideKeyboard() {
        (requireActivity().getSystemService(Activity.INPUT_METHOD_SERVICE) as InputMethodManager).also { imm ->
            val view = view
            if(view != null) {
                imm.hideSoftInputFromWindow(view.windowToken, 0);
            }
        }
    }
+
+    fun onSaveButtonClicked() {
+        presenter.onSaveButtonClicked()
+    }
 }
diff --git a/...nden/simplestackdemoexamplefragments/presentation/paths/addoredittask/AddOrEditTaskKey.kt b/...nden/simplestackdemoexamplefragments/presentation/paths/addoredittask/AddOrEditTaskKey.kt
@@ -2,22 +2,33 @@ package com.zhuinden.simplestackdemoexamplefragments.presentation.paths.addoredi

 import android.support.v4.app.Fragment
 import android.view.View
+import com.zhuinden.simplestack.ScopedServices
 import com.zhuinden.simplestackdemoexamplefragments.R
 import com.zhuinden.simplestackdemoexamplefragments.application.BaseKey
+import com.zhuinden.simplestackdemoexamplefragments.application.Injector
 import com.zhuinden.simplestackdemoexamplefragments.application.Key
+import com.zhuinden.simplestackdemoexamplefragments.util.scopedservices.HasServices
 import kotlinx.android.parcel.Parcelize

 /**
 * Created by Zhuinden on 2018. 08. 20.
 */
-sealed class AddOrEditTaskKey(val parent: Key, val taskId: String = "") : BaseKey() {
+sealed class AddOrEditTaskKey(val parent: Key, val taskId: String = "") : BaseKey(), HasServices {
+    override fun bindServices(serviceBinder: ScopedServices.ServiceBinder) {
+        serviceBinder.add(AddOrEditTaskFragment.CONTROLLER_TAG, Injector.get().addOrEditTaskPresenter())
+    }
+
    constructor(parent: Key) : this(parent, "")

    @Parcelize
-    data class AddTaskKey(val parentKey: Key): AddOrEditTaskKey(parentKey)
+    data class AddTaskKey(val parentKey: Key): AddOrEditTaskKey(parentKey) {
+        override fun getScopeTag(): String = "AddTask"
+    }

    @Parcelize
-    data class EditTaskKey(val parentKey: Key, val taskID: String): AddOrEditTaskKey(parentKey, taskID)
+    data class EditTaskKey(val parentKey: Key, val taskID: String): AddOrEditTaskKey(parentKey, taskID) {
+        override fun getScopeTag(): String = "EditTask[$taskID]"
+    }

    override fun layout(): Int = R.layout.path_addoredittask

@@ -35,9 +46,7 @@ sealed class AddOrEditTaskKey(val parent: Key, val taskId: String = "") : BaseKe
    override fun fabClickListener(fragment: Fragment): View.OnClickListener =
        View.OnClickListener { v ->
            val addOrEditTaskFragment = fragment as AddOrEditTaskFragment
-            if (addOrEditTaskFragment.saveTask()) {
-                addOrEditTaskFragment.navigateBack()
-            }
+            addOrEditTaskFragment.onSaveButtonClicked()
        }


diff --git a/...implestackdemoexamplefragments/presentation/paths/addoredittask/AddOrEditTaskPresenter.kt b/...implestackdemoexamplefragments/presentation/paths/addoredittask/AddOrEditTaskPresenter.kt
@@ -9,7 +9,6 @@ import com.zhuinden.simplestackdemoexamplefragments.presentation.objects.Task
 import com.zhuinden.simplestackdemoexamplefragments.presentation.paths.tasks.TasksFragment
 import com.zhuinden.simplestackdemoexamplefragments.presentation.paths.tasks.TasksKey
 import com.zhuinden.simplestackdemoexamplefragments.util.BasePresenter
-import com.zhuinden.simplestackdemoexamplefragments.util.BaseViewContract
 import com.zhuinden.simplestackdemoexamplefragments.util.MessageQueue
 import com.zhuinden.statebundle.StateBundle
 import io.reactivex.android.schedulers.AndroidSchedulers
@@ -23,15 +22,7 @@ class AddOrEditTaskPresenter @Inject constructor(
    private val taskRepository: TaskRepository,
    private val messageQueue: MessageQueue,
    private val backstack: Backstack
-) : BasePresenter<AddOrEditTaskPresenter.ViewContract>(), Bundleable {
-    interface ViewContract: BaseViewContract {
-        fun setTitle(title: String)
-
-        fun setDescription(description: String)
-
-        fun hideKeyboard()
-    }
-
+) : BasePresenter<AddOrEditTaskFragment>(), AddOrEditTaskFragment.Presenter, Bundleable {
    var title: String? = null
    var description: String? = null

@@ -48,7 +39,7 @@ class AddOrEditTaskPresenter @Inject constructor(
    }

    @SuppressLint("CheckResult")
-    override fun onAttach(view: ViewContract) {
+    override fun onAttach(view: AddOrEditTaskFragment) {
        val addOrEditTaskKey: AddOrEditTaskKey = view.getKey()
        taskId = addOrEditTaskKey.taskId

@@ -68,7 +59,21 @@ class AddOrEditTaskPresenter @Inject constructor(
        }
    }

-    override fun onDetach(view: ViewContract) {
+    override fun onDetach(view: AddOrEditTaskFragment) {
+    }
+
+    override fun onTitleChanged(title: String) {
+        updateTitle(title)
+    }
+
+    override fun onDescriptionChanged(description: String) {
+        updateDescription(description)
+    }
+
+    override fun onSaveButtonClicked() {
+        if (saveTask()) {
+            navigateBack()
+        }
    }

    override fun toBundle(): StateBundle = StateBundle().apply {
@@ -83,7 +88,7 @@ class AddOrEditTaskPresenter @Inject constructor(
        }
    }

-    fun saveTask(): Boolean {
+    private fun saveTask(): Boolean {
        val task = task
        val title = title
        val description = description
@@ -100,7 +105,7 @@ class AddOrEditTaskPresenter @Inject constructor(
        return false
    }

-    fun navigateBack() {
+    private fun navigateBack() {
        view!!.hideKeyboard()
        val addOrEditTaskKey = view!!.getKey<AddOrEditTaskKey>()
        when(addOrEditTaskKey) {
diff --git a/...inden/simplestackdemoexamplefragments/presentation/paths/statistics/StatisticsFragment.kt b/...inden/simplestackdemoexamplefragments/presentation/paths/statistics/StatisticsFragment.kt
@@ -3,17 +3,28 @@ package com.zhuinden.simplestackdemoexamplefragments.presentation.paths.statisti
 import com.zhuinden.simplestackdemoexamplefragments.R
 import com.zhuinden.simplestackdemoexamplefragments.application.Injector
 import com.zhuinden.simplestackdemoexamplefragments.util.BaseFragment
+import com.zhuinden.simplestackdemoexamplefragments.util.MvpPresenter
+import com.zhuinden.simplestackdemoexamplefragments.util.backstackDelegate
 import kotlinx.android.synthetic.main.path_statistics.*

 /**
 * Created by Zhuinden on 2018. 08. 20.
 */
 // UNSCOPED!
-class StatisticsFragment : BaseFragment<StatisticsPresenter.ViewContract, StatisticsPresenter>(), StatisticsPresenter.ViewContract {
+class StatisticsFragment : BaseFragment<StatisticsFragment, StatisticsFragment.Presenter>() {
    private val myResources = Injector.get().resources()
-    private val statisticsPresenter = Injector.get().statisticsPresenter()

-    override val presenter: StatisticsPresenter = statisticsPresenter
+    companion object {
+        const val CONTROLLER_TAG = "AddOrEditTaskPresenter"
+    }
+
+    interface Presenter: MvpPresenter<StatisticsFragment> {
+    }
+
+    override val presenter: Presenter by lazy {
+        backstackDelegate.lookupService<StatisticsFragment.Presenter>(CONTROLLER_TAG)
+    }
+
    override fun getThis(): StatisticsFragment = this

    fun setProgressIndicator(active: Boolean) {
@@ -23,7 +34,7 @@ class StatisticsFragment : BaseFragment<StatisticsPresenter.ViewContract, Statis
        }
    }

-    override fun showStatistics(numberOfIncompleteTasks: Int, numberOfCompletedTasks: Int) {
+    fun showStatistics(numberOfIncompleteTasks: Int, numberOfCompletedTasks: Int) {
        textStatistics.text = when {
            numberOfCompletedTasks == 0 && numberOfIncompleteTasks == 0 -> myResources.getString(R.string.statistics_no_tasks)
            else ->
diff --git a/...m/zhuinden/simplestackdemoexamplefragments/presentation/paths/statistics/StatisticsKey.kt b/...m/zhuinden/simplestackdemoexamplefragments/presentation/paths/statistics/StatisticsKey.kt
@@ -2,15 +2,24 @@ package com.zhuinden.simplestackdemoexamplefragments.presentation.paths.statisti

 import android.support.v4.app.Fragment
 import android.view.View
+import com.zhuinden.simplestack.ScopedServices
 import com.zhuinden.simplestackdemoexamplefragments.R
 import com.zhuinden.simplestackdemoexamplefragments.application.BaseKey
+import com.zhuinden.simplestackdemoexamplefragments.application.Injector
+import com.zhuinden.simplestackdemoexamplefragments.util.scopedservices.HasServices
 import kotlinx.android.parcel.Parcelize

 /**
 * Created by Zhuinden on 2018. 08. 20.
 */
 @Parcelize
-data class StatisticsKey(val placeholder: String = "") : BaseKey() {
+data class StatisticsKey(val placeholder: String = "") : BaseKey(), HasServices {
+    override fun bindServices(serviceBinder: ScopedServices.ServiceBinder) {
+        serviceBinder.add(StatisticsFragment.CONTROLLER_TAG, Injector.get().statisticsPresenter())
+    }
+
+    override fun getScopeTag(): String = "Statistics"
+
    constructor() : this("")

    override fun layout(): Int = R.layout.path_statistics
diff --git a/...nden/simplestackdemoexamplefragments/presentation/paths/statistics/StatisticsPresenter.kt b/...nden/simplestackdemoexamplefragments/presentation/paths/statistics/StatisticsPresenter.kt
@@ -2,9 +2,7 @@ package com.zhuinden.simplestackdemoexamplefragments.presentation.paths.statisti

 import com.zhuinden.simplestackdemoexamplefragments.data.repository.TaskRepository
 import com.zhuinden.simplestackdemoexamplefragments.util.BasePresenter
-import com.zhuinden.simplestackdemoexamplefragments.util.BaseViewContract
 import com.zhuinden.simplestackdemoexamplefragments.util.combineTwo
-import com.zhuinden.statebundle.StateBundle
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.disposables.Disposable
 import io.reactivex.schedulers.Schedulers
@@ -16,14 +14,10 @@ import javax.inject.Inject

 class StatisticsPresenter @Inject constructor(
    private val taskRepository: TaskRepository
-) : BasePresenter<StatisticsPresenter.ViewContract>() {
-    interface ViewContract: BaseViewContract {
-        fun showStatistics(numberOfIncompleteTasks: Int, numberOfCompletedTasks: Int)
-    }
-
+) : BasePresenter<StatisticsFragment>(), StatisticsFragment.Presenter {
    private lateinit var disposable: Disposable

-    override fun onAttach(view: StatisticsPresenter.ViewContract) {
+    override fun onAttach(view: StatisticsFragment) {
        disposable = combineTwo(
            taskRepository.activeTasksWithChanges,
            taskRepository.completedTasksWithChanges)
@@ -34,12 +28,7 @@ class StatisticsPresenter @Inject constructor(
            }
    }

-    override fun onDetach(view: StatisticsPresenter.ViewContract) {
+    override fun onDetach(view: StatisticsFragment) {
        disposable.dispose()
    }
-
-    override fun toBundle(): StateBundle = StateBundle()
-
-    override fun fromBundle(bundle: StateBundle?) {
-    }
 }