Issue #18535: Set the span count for grid view

app/src/main/java/org/mozilla/fenix/tabstray/TabsTrayFragment.kt

@@ -77,7 +77,8 @@ class TabsTrayFragment : AppCompatDialogFragment(), TabsTrayInteractor {
         val browserTrayInteractor = DefaultBrowserTrayInteractor(
             this,
             selectTabUseCase,
-            removeUseCases
+            removeUseCases,
+            requireComponents.settings
         )
 
         val syncedTabsTrayInteractor = SyncedTabsInteractor(

app/src/main/java/org/mozilla/fenix/tabstray/TrayPagerAdapter.kt

@@ -7,7 +7,6 @@ package org.mozilla.fenix.tabstray
 import android.content.Context
 import android.view.LayoutInflater
 import android.view.ViewGroup
-import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import org.mozilla.fenix.tabstray.browser.BrowserTabsAdapter
 import org.mozilla.fenix.tabstray.browser.BrowserTrayInteractor
@@ -57,7 +56,7 @@ class TrayPagerAdapter(
             else -> throw IllegalStateException("View type does not exist.")
         }
 
-        viewHolder.bind(adapter, GridLayoutManager(context, 1))
+        viewHolder.bind(adapter, browserInteractor.getLayoutManagerForPosition(context, position))
     }
 
     override fun getItemViewType(position: Int): Int {

app/src/main/java/org/mozilla/fenix/tabstray/browser/BrowserTrayInteractor.kt

@@ -4,9 +4,15 @@
 
 package org.mozilla.fenix.tabstray.browser
 
+import android.content.Context
+import androidx.recyclerview.widget.GridLayoutManager
+import androidx.recyclerview.widget.RecyclerView
 import mozilla.components.concept.tabstray.Tab
 import mozilla.components.feature.tabs.TabsUseCases
 import org.mozilla.fenix.tabstray.TabsTrayInteractor
+import org.mozilla.fenix.tabstray.TrayPagerAdapter
+import org.mozilla.fenix.tabstray.ext.numberOfGridColumns
+import org.mozilla.fenix.utils.Settings
 
 /**
  * For interacting with UI that is specifically for [BaseBrowserTrayList] and other browser
@@ -28,6 +34,11 @@ interface BrowserTrayInteractor {
      * If multi-select mode is enabled or disabled.
      */
     fun isMultiSelectMode(): Boolean
+
+    /**
+     * Returns the appropriate [RecyclerView.LayoutManager] to be used at [position].
+     */
+    fun getLayoutManagerForPosition(context: Context, position: Int): RecyclerView.LayoutManager
 }
 
 /**
@@ -36,7 +47,8 @@ interface BrowserTrayInteractor {
 class DefaultBrowserTrayInteractor(
     private val trayInteractor: TabsTrayInteractor,
     private val selectTabUseCase: TabsUseCases.SelectTabUseCase,
-    private val removeUseCases: TabsUseCases.RemoveTabUseCase
+    private val removeUseCases: TabsUseCases.RemoveTabUseCase,
+    private val settings: Settings
 ) : BrowserTrayInteractor {
 
     /**
@@ -61,4 +73,23 @@ class DefaultBrowserTrayInteractor(
         // Needs https://github.com/mozilla-mobile/fenix/issues/18513 to change this value
         return false
     }
+
+    override fun getLayoutManagerForPosition(
+        context: Context,
+        position: Int
+    ): RecyclerView.LayoutManager {
+        if (position == TrayPagerAdapter.POSITION_SYNCED_TABS) {
+            // Lists are just Grids with one column :)
+            return GridLayoutManager(context, 1)
+        }
+
+        // Normal/Private tabs
+        val numberOfColumns = if (settings.gridTabView) {
+            context.numberOfGridColumns
+        } else {
+            1
+        }
+
+        return GridLayoutManager(context, numberOfColumns)
+    }
 }

app/src/main/java/org/mozilla/fenix/tabstray/ext/Context.kt

@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.tabstray.ext
+
+import android.content.Context
+
+private const val MIN_COLUMN_WIDTH_DP = 180
+
+/**
+ * Returns the number of grid columns we can fit on the screen in the tabs tray.
+ */
+internal val Context.numberOfGridColumns: Int
+    get() {
+        val displayMetrics = resources.displayMetrics
+        val screenWidthDp = displayMetrics.widthPixels / displayMetrics.density
+        return (screenWidthDp / MIN_COLUMN_WIDTH_DP).toInt()
+    }

app/src/test/java/org/mozilla/fenix/tabstray/browser/DefaultBrowserTrayInteractorTest.kt

@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.tabstray.browser
+
+import android.content.Context
+import androidx.recyclerview.widget.GridLayoutManager
+import io.mockk.every
+import io.mockk.mockk
+import io.mockk.mockkStatic
+import io.mockk.unmockkStatic
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+import org.mozilla.fenix.tabstray.TrayPagerAdapter
+import org.mozilla.fenix.tabstray.ext.numberOfGridColumns
+import org.mozilla.fenix.utils.Settings
+
+class DefaultBrowserTrayInteractorTest {
+
+    @Before
+    fun setup() {
+        mockkStatic("org.mozilla.fenix.tabstray.ext.ContextKt")
+    }
+
+    @After
+    fun shutdown() {
+        unmockkStatic("org.mozilla.fenix.tabstray.ext.ContextKt")
+    }
+
+    @Test
+    fun `WHEN pager position is synced tabs THEN return a list layout manager`() {
+        val interactor = DefaultBrowserTrayInteractor(mockk(), mockk(), mockk(), mockk())
+
+        val result = interactor.getLayoutManagerForPosition(
+            mockk(),
+            TrayPagerAdapter.POSITION_SYNCED_TABS
+        )
+
+        assertEquals(1, (result as GridLayoutManager).spanCount)
+    }
+
+    @Test
+    fun `WHEN setting is grid view THEN return grid layout manager`() {
+        val context = mockk<Context>()
+        val settings = mockk<Settings>()
+        val interactor = DefaultBrowserTrayInteractor(mockk(), mockk(), mockk(), settings)
+
+        every { context.numberOfGridColumns }.answers { 4 }
+        every { settings.gridTabView }.answers { true }
+
+        val result = interactor.getLayoutManagerForPosition(
+            context,
+            TrayPagerAdapter.POSITION_NORMAL_TABS
+        )
+
+        assertEquals(4, (result as GridLayoutManager).spanCount)
+    }
+
+    @Test
+    fun `WHEN setting is list view THEN return list layout manager`() {
+        val context = mockk<Context>()
+        val settings = mockk<Settings>()
+        val interactor = DefaultBrowserTrayInteractor(mockk(), mockk(), mockk(), settings)
+
+        every { context.numberOfGridColumns }.answers { 4 }
+        every { settings.gridTabView }.answers { false }
+
+        val result = interactor.getLayoutManagerForPosition(
+            context,
+            TrayPagerAdapter.POSITION_NORMAL_TABS
+        )
+
+        // Should NOT be 4.
+        assertEquals(1, (result as GridLayoutManager).spanCount)
+    }
+}