Remove leftover tasks from previous Emacs sessions on startup

* java/org/gnu/emacs/EmacsService.java (onCreate): Call
removeOldTasks.

* java/org/gnu/emacs/EmacsWindowManager.java (removeOldTasks):
New function.

* java/proguard.conf: Optimize optimizer configuration.

2 files changed, 50 insertions, 3 deletions

diff --git a/java/org/gnu/emacs/EmacsService.java b/java/org/gnu/emacs/EmacsService.java
index b8ff98e79a7..fd052653087 100644
--- a/java/org/gnu/emacs/EmacsService.java
+++ b/java/org/gnu/emacs/EmacsService.java
@@ -234,6 +234,8 @@ public final class EmacsService extends Service
     final double scaledDensity;
     double tempScaledDensity;
 
+    super.onCreate ();
+
     SERVICE = this;
     handler = new Handler (Looper.getMainLooper ());
     manager = getAssets ();
@@ -247,9 +249,9 @@ public final class EmacsService extends Service
     resolver = getContentResolver ();
     mainThread = Thread.currentThread ();
 
-    /* If the density used to compute the text size is lesser than
-       160, there's likely a bug with display density computation.
-       Reset it to 160 in that case.
+    /* If the density used to compute the text size is smaller than 160,
+       there's likely a bug with display density computation.  Reset it
+       to 160 in that case.
 
        Note that Android uses 160 ``dpi'' as the density where 1 point
        corresponds to 1 pixel, not 72 or 96 as used elsewhere.  This
@@ -262,6 +264,10 @@ public final class EmacsService extends Service
        the nested function below.  */
     scaledDensity = tempScaledDensity;
 
+    /* Remove all tasks from previous Emacs sessions but the task
+       created by the system at startup.  */
+    EmacsWindowManager.MANAGER.removeOldTasks (this);
+
     try
       {
         /* Configure Emacs with the asset manager and other necessary
diff --git a/java/org/gnu/emacs/EmacsWindowManager.java b/java/org/gnu/emacs/EmacsWindowManager.java
index a193d49d0ec..49f0ebd5841 100644
--- a/java/org/gnu/emacs/EmacsWindowManager.java
+++ b/java/org/gnu/emacs/EmacsWindowManager.java
@@ -27,6 +27,7 @@ import android.app.ActivityManager.RecentTaskInfo;
 import android.app.ActivityManager;
 import android.app.ActivityOptions;
 
+import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 
@@ -385,4 +386,44 @@ public final class EmacsWindowManager
         window.onActivityDetached ();
       }
   }
+
+  /* Iterate over each of Emacs's tasks to delete such as belong to a
+     previous Emacs session, i.e., tasks created for a previous
+     session's non-initial frames.  CONTEXT should be a context from
+     which to obtain a reference to the activity manager.  */
+
+  public void
+  removeOldTasks (Context context)
+  {
+    List<AppTask> appTasks;
+    RecentTaskInfo info;
+    ComponentName name;
+    String target;
+    Object object;
+
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP)
+      return;
+
+    if (activityManager == null)
+      {
+        object = context.getSystemService (Context.ACTIVITY_SERVICE);
+        activityManager = (ActivityManager) object;
+      }
+
+    appTasks = activityManager.getAppTasks ();
+    target   = ".EmacsMultitaskActivity";
+
+    for (AppTask task : appTasks)
+      {
+        info = task.getTaskInfo ();
+
+        /* Test whether info is a reference to
+           EmacsMultitaskActivity.  */
+        if (info.baseIntent != null
+            && (name = info.baseIntent.getComponent ()) != null
+            && name.getShortClassName ().equals (target))
+          /* Delete the task.  */
+          task.finishAndRemoveTask ();
+      }
+  }
 };