From 138c24fb136cdbd3953f81cbb7e6b875877fc0f4 Mon Sep 17 00:00:00 2001
From: Darryl L Johnson <darryljohnson@google.com>
Date: Fri, 5 Jun 2020 12:20:32 -0700
Subject: [PATCH] Ensure split-screen support isn't reported on devices with
 small displays.

Several partners with devices that have small displays have run into
issues w/ CTS-on-GSI testing as these builds hardcode support for
split-screen. This prevents split-screen from being reported as
supported if the display isn't compatible according to the CDD.

Bug: 158310372
Test: android.server.wm.SplitScreenTests#testMinimumDeviceSize()

Change-Id: I0dfd6caca5116dccc115d64b755998171abe831f
---
 api/test-current.txt                          |  1 +
 .../java/android/app/ActivityTaskManager.java | 20 ++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/api/test-current.txt b/api/test-current.txt
index e788e6f6d8e25..b701948d6b497 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -143,6 +143,7 @@ package android.app {
     method @RequiresPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS) public void stopSystemLockTaskMode();
     method public static boolean supportsMultiWindow(android.content.Context);
     method public static boolean supportsSplitScreenMultiWindow(android.content.Context);
+    field public static final int DEFAULT_MINIMAL_SPLIT_SCREEN_DISPLAY_SIZE_DP = 440; // 0x1b8
     field public static final int INVALID_STACK_ID = -1; // 0xffffffff
     field public static final int SPLIT_SCREEN_CREATE_MODE_BOTTOM_OR_RIGHT = 1; // 0x1
     field public static final int SPLIT_SCREEN_CREATE_MODE_TOP_OR_LEFT = 0; // 0x0
diff --git a/core/java/android/app/ActivityTaskManager.java b/core/java/android/app/ActivityTaskManager.java
index 1cc63da3db0a6..ef9034d8fa6b0 100644
--- a/core/java/android/app/ActivityTaskManager.java
+++ b/core/java/android/app/ActivityTaskManager.java
@@ -31,6 +31,7 @@ import android.os.Handler;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.os.ServiceManager;
+import android.util.DisplayMetrics;
 import android.util.Singleton;
 
 import java.util.List;
@@ -139,6 +140,8 @@ public class ActivityTaskManager {
     public static final String EXTRA_IGNORE_TARGET_SECURITY =
             "android.app.extra.EXTRA_IGNORE_TARGET_SECURITY";
 
+    /** The minimal size of a display's long-edge needed to support split-screen multi-window. */
+    public static final int DEFAULT_MINIMAL_SPLIT_SCREEN_DISPLAY_SIZE_DP = 440;
 
     private static int sMaxRecentTasks = -1;
 
@@ -282,8 +285,23 @@ public class ActivityTaskManager {
                 com.android.internal.R.bool.config_supportsMultiWindow);
     }
 
-    /** Returns true if the system supports split screen multi-window. */
+    /**
+     * Returns {@code true} if the display the context is associated with supports split screen
+     * multi-window.
+     *
+     * @throws UnsupportedOperationException if the supplied {@link Context} is not associated with
+     * a display.
+     */
     public static boolean supportsSplitScreenMultiWindow(Context context) {
+        DisplayMetrics dm = new DisplayMetrics();
+        context.getDisplay().getRealMetrics(dm);
+
+        int widthDp = (int) (dm.widthPixels / dm.density);
+        int heightDp = (int) (dm.heightPixels / dm.density);
+        if (Math.max(widthDp, heightDp) < DEFAULT_MINIMAL_SPLIT_SCREEN_DISPLAY_SIZE_DP) {
+            return false;
+        }
+
         return supportsMultiWindow(context)
                 && Resources.getSystem().getBoolean(
                 com.android.internal.R.bool.config_supportsSplitScreenMultiWindow);