[MBL-17287][Teacher] Add dashboard card reordering functionality

Implemented drag-and-drop reordering for dashboard cards in Teacher app,
matching the Student app functionality. Cards can be reordered by dragging,
and positions persist across app restarts via API persistence and cache
invalidation.

Changes:
- DashboardFragment: Added ItemTouchHelper for drag-and-drop, cancelCardDrag()
  safety method to handle tab switching during drag
- DashboardPresenter: Added moveCourse() for local reordering,
  saveDashboardPositions() for API persistence with cache invalidation,
  isOnline() check to disable dragging when offline
- DashboardPresenterFactory: Updated to inject UserAPI and NetworkStateProvider
- InitActivity: Added call to cancelCardDrag() when switching bottom nav tabs
  to prevent UI glitches

Key features:
- Drag-and-drop only enabled when online
- Position persistence via API with cache invalidation strategy
- Cancel drag gesture when switching tabs for clean UX
- Error handling with toast notification on save failure

Test plan:
- Verify cards can be dragged and reordered in grid/list views
- Verify positions persist after app restart
- Verify dragging is disabled when offline
- Verify switching tabs while dragging cancels the gesture cleanly
- Verify error toast appears if position save fails

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: kristofnemere

apps/teacher/src/main/java/com/instructure/teacher/activities/InitActivity.kt

@@ -158,6 +158,9 @@ class InitActivity : BasePresenterActivity<InitActivityPresenter, InitActivityVi
     private var drawerItemSelectedJob: Job? = null
 
     private val mTabSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
+        // Cancel any active drag on dashboard before switching tabs
+        (supportFragmentManager.findFragmentByTag(DashboardFragment::class.java.simpleName) as? DashboardFragment)?.cancelCardDrag()
+
         selectedTab = when (item.itemId) {
             R.id.tab_courses -> {
                 addCoursesFragment()

apps/teacher/src/main/java/com/instructure/teacher/factory/DashboardPresenterFactory.kt

@@ -17,10 +17,15 @@
 package com.instructure.teacher.factory
 
 
+import com.instructure.canvasapi2.apis.UserAPI
+import com.instructure.pandautils.utils.NetworkStateProvider
 import com.instructure.teacher.presenters.DashboardPresenter
 import com.instructure.teacher.viewinterface.CoursesView
 import com.instructure.pandautils.blueprint.PresenterFactory
 
-class DashboardPresenterFactory : PresenterFactory<CoursesView, DashboardPresenter> {
-    override fun create() = DashboardPresenter()
+class DashboardPresenterFactory(
+    private val userApi: UserAPI.UsersInterface,
+    private val networkStateProvider: NetworkStateProvider
+) : PresenterFactory<CoursesView, DashboardPresenter> {
+    override fun create() = DashboardPresenter(userApi, networkStateProvider)
 }

apps/teacher/src/main/java/com/instructure/teacher/fragments/DashboardFragment.kt

@@ -20,10 +20,15 @@ import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
 import android.view.MenuItem
+import android.view.MotionEvent
+import android.view.MotionEvent.ACTION_CANCEL
 import android.view.View
+import androidx.lifecycle.lifecycleScope
 import androidx.localbroadcastmanager.content.LocalBroadcastManager
 import androidx.recyclerview.widget.GridLayoutManager
+import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.RecyclerView
+import com.instructure.canvasapi2.apis.UserAPI
 import com.instructure.canvasapi2.models.Course
 import com.instructure.canvasapi2.utils.ApiPrefs
 import com.instructure.canvasapi2.utils.pageview.PageView
@@ -33,7 +38,18 @@ import com.instructure.pandautils.binding.viewBinding
 import com.instructure.pandautils.features.dashboard.edit.EditDashboardFragment
 import com.instructure.pandautils.features.dashboard.notifications.DashboardNotificationsFragment
 import com.instructure.pandautils.fragments.BaseSyncFragment
-import com.instructure.pandautils.utils.*
+import com.instructure.pandautils.utils.Const
+import com.instructure.pandautils.utils.NetworkStateProvider
+import com.instructure.pandautils.utils.ThemePrefs
+import com.instructure.pandautils.utils.Utils
+import com.instructure.pandautils.utils.ViewStyler
+import com.instructure.pandautils.utils.fadeAnimationWithAction
+import com.instructure.pandautils.utils.getDrawableCompat
+import com.instructure.pandautils.utils.requestAccessibilityFocus
+import com.instructure.pandautils.utils.setGone
+import com.instructure.pandautils.utils.setVisible
+import com.instructure.pandautils.utils.setupAsBackButton
+import com.instructure.pandautils.utils.toast
 import com.instructure.teacher.R
 import com.instructure.teacher.activities.InitActivity
 import com.instructure.teacher.adapters.CoursesAdapter
@@ -49,16 +65,26 @@ import com.instructure.teacher.utils.RecyclerViewUtils
 import com.instructure.teacher.utils.TeacherPrefs
 import com.instructure.teacher.utils.setupMenu
 import com.instructure.teacher.viewinterface.CoursesView
+import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.launch
 import org.greenrobot.eventbus.EventBus
 import org.greenrobot.eventbus.Subscribe
 import org.greenrobot.eventbus.ThreadMode
+import javax.inject.Inject
 
 private const val LIST_SPAN_COUNT = 1
 
 @PageView
 @ScreenView(SCREEN_VIEW_DASHBOARD)
+@AndroidEntryPoint
 class DashboardFragment : BaseSyncFragment<Course, DashboardPresenter, CoursesView, CoursesViewHolder, CoursesAdapter>(), CoursesView {
 
+    @Inject
+    lateinit var userApi: UserAPI.UsersInterface
+
+    @Inject
+    lateinit var networkStateProvider: NetworkStateProvider
+
     private val binding by viewBinding(FragmentDashboardBinding::bind)
 
     private lateinit var mGridLayoutManager: GridLayoutManager
@@ -82,7 +108,7 @@ class DashboardFragment : BaseSyncFragment<Course, DashboardPresenter, CoursesVi
     override fun perPageCount() = ApiPrefs.perPageCount
     override fun withPagination() = false
 
-    override fun getPresenterFactory() = DashboardPresenterFactory()
+    override fun getPresenterFactory() = DashboardPresenterFactory(userApi, networkStateProvider)
 
     override fun onAttach(context: Context) {
         super.onAttach(context)
@@ -141,6 +167,7 @@ class DashboardFragment : BaseSyncFragment<Course, DashboardPresenter, CoursesVi
         if(courseRecyclerView.adapter == null) {
             courseRecyclerView.adapter = adapter
         }
+        addItemTouchHelperForCardReorder()
         presenter.loadData(mNeedToForceNetwork)
         mNeedToForceNetwork = false
     }
@@ -234,6 +261,84 @@ class DashboardFragment : BaseSyncFragment<Course, DashboardPresenter, CoursesVi
         RecyclerViewUtils.checkIfEmpty(emptyCoursesView, courseRecyclerView, swipeRefreshLayout, adapter, presenter.isEmpty)
     }
 
+    private fun addItemTouchHelperForCardReorder() {
+        val itemTouchHelper = ItemTouchHelper(object : ItemTouchHelper.SimpleCallback(
+            ItemTouchHelper.START or ItemTouchHelper.END or ItemTouchHelper.DOWN or ItemTouchHelper.UP,
+            0
+        ) {
+            private var draggedFromPosition: Int? = null
+
+            override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
+                super.onSelectedChanged(viewHolder, actionState)
+
+                if (viewHolder != null && actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
+                    draggedFromPosition = viewHolder.bindingAdapterPosition
+                }
+            }
+
+            override fun onMove(
+                recyclerView: RecyclerView,
+                viewHolder: RecyclerView.ViewHolder,
+                target: RecyclerView.ViewHolder
+            ): Boolean {
+                val fromPosition = viewHolder.bindingAdapterPosition
+                val toPosition = target.bindingAdapterPosition
+
+                if (fromPosition in 0 until adapter.size() && toPosition in 0 until adapter.size()) {
+                    adapter.notifyItemMoved(fromPosition, toPosition)
+                }
+
+                return true
+            }
+
+            override fun getDragDirs(
+                recyclerView: RecyclerView,
+                viewHolder: RecyclerView.ViewHolder
+            ): Int {
+                return if (viewHolder is CoursesViewHolder && presenter.isOnline()) {
+                    ItemTouchHelper.START or ItemTouchHelper.END or ItemTouchHelper.DOWN or ItemTouchHelper.UP
+                } else 0
+            }
+
+            override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) = Unit
+
+            override fun clearView(
+                recyclerView: RecyclerView,
+                viewHolder: RecyclerView.ViewHolder
+            ) {
+                super.clearView(recyclerView, viewHolder)
+
+                val finishingPosition = viewHolder.bindingAdapterPosition
+                val startPosition = draggedFromPosition
+
+                if (finishingPosition == RecyclerView.NO_POSITION || startPosition == null) {
+                    draggedFromPosition = null
+                    return
+                }
+
+                if (startPosition != finishingPosition) {
+                    presenter.moveCourse(startPosition, finishingPosition)
+                    adapter.notifyDataSetChanged()
+
+                    lifecycleScope.launch {
+                        val result = presenter.saveDashboardPositions()
+                        if (result.isFail) {
+                            toast(R.string.failedToUpdateDashboardOrder)
+                        }
+                    }
+                }
+
+                draggedFromPosition = null
+            }
+        })
+
+        itemTouchHelper.attachToRecyclerView(binding.courseRecyclerView)
+    }
+
+    fun cancelCardDrag() {
+        binding.courseRecyclerView.onTouchEvent(MotionEvent.obtain(0L, 0L, ACTION_CANCEL, 0f, 0f, 0))
+    }
+
     companion object {
         fun getInstance() = DashboardFragment()
     }

apps/teacher/src/main/java/com/instructure/teacher/presenters/DashboardPresenter.kt

@@ -15,21 +15,31 @@
  */
 package com.instructure.teacher.presenters
 
+import com.instructure.canvasapi2.CanvasRestAdapter
+import com.instructure.canvasapi2.apis.UserAPI
+import com.instructure.canvasapi2.builders.RestParams
 import com.instructure.canvasapi2.managers.CourseManager
 import com.instructure.canvasapi2.models.Course
 import com.instructure.canvasapi2.models.DashboardCard
+import com.instructure.canvasapi2.models.DashboardPositions
 import com.instructure.canvasapi2.models.Tab
 import com.instructure.canvasapi2.utils.ApiPrefs
+import com.instructure.canvasapi2.utils.DataResult
 import com.instructure.canvasapi2.utils.weave.apiAsync
+import com.instructure.pandarecycler.util.toList
 import com.instructure.pandautils.blueprint.SyncPresenter
 import com.instructure.pandautils.utils.ColorApiHelper
+import com.instructure.pandautils.utils.NetworkStateProvider
 import com.instructure.teacher.viewinterface.CoursesView
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
 
-class DashboardPresenter : SyncPresenter<Course, CoursesView>(Course::class.java) {
+class DashboardPresenter(
+    private val userApi: UserAPI.UsersInterface,
+    private val networkStateProvider: NetworkStateProvider
+) : SyncPresenter<Course, CoursesView>(Course::class.java) {
 
     private var dashboardJob: Job? = null
 
@@ -113,4 +123,33 @@ class DashboardPresenter : SyncPresenter<Course, CoursesView>(Course::class.java
     override fun areContentsTheSame(item1: Course, item2: Course): Boolean {
         return item1.contextId.hashCode() == item2.contextId.hashCode()
     }
+
+    fun moveCourse(fromPosition: Int, toPosition: Int) {
+        if (fromPosition < 0 || toPosition < 0 || fromPosition >= data.size() || toPosition >= data.size()) {
+            return
+        }
+        val courses = data.toList().toMutableList()
+        val movedCourse = courses.removeAt(fromPosition)
+        courses.add(toPosition, movedCourse)
+        data.clear()
+        data.addOrUpdate(courses)
+    }
+
+    suspend fun saveDashboardPositions(): DataResult<DashboardPositions> {
+        val courses = data.toList()
+        val positions = courses
+            .mapIndexed { index, course -> Pair(course.contextId, index) }
+            .toMap()
+        val dashboardPositions = DashboardPositions(positions)
+
+        val result = userApi.updateDashboardPositions(dashboardPositions, RestParams(isForceReadFromNetwork = true))
+        if (result is DataResult.Success) {
+            CanvasRestAdapter.clearCacheUrls("dashboard/dashboard_cards")
+        }
+        return result
+    }
+
+    fun isOnline(): Boolean {
+        return networkStateProvider.isOnline()
+    }
 }