Disabling the activate button when paused

This revises the previous attempt to drop taps when another window is
obscuring the device admin details. Any system alert windows or toasts
are disabled when the activity is in focus, otherwise the button is
disabled so no floating activities can obscure it and delegate taps back
to the security sensitive "Activate" button.

Bug: 35056974
Change-Id: I292a44e713ea4a4b0305ca3b3b21f1c82fd73c2b
Merged-In: I292a44e713ea4a4b0305ca3b3b21f1c82fd73c2b

src/com/android/settings/DeviceAdminAdd.java

@@ -16,6 +16,8 @@
 
 package com.android.settings;
 
+import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
+
 import org.xmlpull.v1.XmlPullParserException;
 
 import android.app.Activity;
@@ -88,7 +90,7 @@ public class DeviceAdminAdd extends Activity {
     @Override
     protected void onCreate(Bundle icicle) {
         super.onCreate(icicle);
-
+        getWindow().addPrivateFlags(PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
         mHandler = new Handler(getMainLooper());
         
         mDPM = (DevicePolicyManager)getSystemService(Context.DEVICE_POLICY_SERVICE);
@@ -264,13 +266,20 @@ public class DeviceAdminAdd extends Activity {
             }
         });
     }
-    
+
     @Override
     protected void onResume() {
         super.onResume();
+        mActionButton.setEnabled(true);
         updateInterface();
     }
-    
+
+    @Override
+    protected void onPause() {
+        super.onPause();
+        mActionButton.setEnabled(false);
+    }
+
     @Override
     protected Dialog onCreateDialog(int id, Bundle args) {
         switch (id) {