Use default encryption password if an accessibility service is enabled.

If accessibility is on and the user selectes a secure lock we use weaker
encryption to enable running accessibility layer at the time the user
authenticates. This change adds a warning message to the enable accessibility
service dialog if there is a secure lock and also adds a warning as a
summary for the secure lock in the lock chooser activity. Both warning
mention the weaker encryption to be used.

bug:17671790

Change-Id: Ib5cc9d3a78f751e18362bb9238fd2804c3b600f8

res/layout/enable_accessibility_service_dialog_content.xml

@@ -28,6 +28,12 @@
         android:paddingStart="16dip"
         android:paddingEnd="16dip" >
 
+        <TextView android:id="@+id/encryption_warning"
+            android:layout_width="fill_parent"
+            android:layout_height="wrap_content"
+            android:padding="10dip"
+            android:textAppearance="?android:attr/textAppearanceMedium"/>
+
         <TextView android:id="@+id/capabilities_header"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"

res/values/strings.xml

@@ -3665,6 +3665,14 @@
     <!-- Title for the list of capabilities of an accessibility service. -->
     <string name="capabilities_list_title"><xliff:g id="service" example="TalkBack">%1$s</xliff:g>
         needs to:</string>
+    <!-- Warning that the device data will not be encrypted with password or PIN if
+        enabling an accessibility service and there is a secure lock setup. [CHAR LIMIT=NONE] -->
+    <string name="enable_service_encryption_warning">If you turn on <xliff:g id="service"
+        example="TalkBack">%1$s</xliff:g>, your data\'s encryption won\'t be as strong.</string>
+    <!-- Warning that the device data will not be encrypted with password or PIN if
+         choosing a secure lock and there is an enabled accessibility service. [CHAR LIMIT=NONE] -->
+    <string name="secure_lock_encryption_warning">Because you\'ve turned on an accessibility service,
+        encryption based on this type of lock won\'t be as strong.</string>
 
     <!-- Title for the capability of an accessibility service to receive events and keys. -->
     <string name="capability_title_receiveAccessibilityEvents">Observe your actions</string>

src/com/android/settings/ChooseLockGeneric.java

@@ -16,6 +16,7 @@
 
 package com.android.settings;
 
+import android.accessibilityservice.AccessibilityServiceInfo;
 import android.app.Activity;
 import android.app.PendingIntent;
 import android.app.admin.DevicePolicyManager;
@@ -32,6 +33,7 @@ import android.util.MutableBoolean;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.accessibility.AccessibilityManager;
 import android.widget.ListView;
 
 import com.android.internal.widget.LockPatternUtils;
@@ -213,6 +215,7 @@ public class ChooseLockGeneric extends SettingsActivity {
                 }
                 addPreferencesFromResource(R.xml.security_settings_picker);
                 disableUnusablePreferences(quality, allowBiometric);
+                updatePreferenceSummaryIfNeeded();
             } else {
                 updateUnlockMethodAndFinish(quality, false);
             }
@@ -292,6 +295,28 @@ public class ChooseLockGeneric extends SettingsActivity {
             }
         }
 
+        private void updatePreferenceSummaryIfNeeded() {
+            if (AccessibilityManager.getInstance(getActivity()).getEnabledAccessibilityServiceList(
+                    AccessibilityServiceInfo.FEEDBACK_ALL_MASK).isEmpty()) {
+                return;
+            }
+
+            CharSequence summary = getString(R.string.secure_lock_encryption_warning);
+
+            PreferenceScreen screen = getPreferenceScreen();
+            final int preferenceCount = screen.getPreferenceCount();
+            for (int i = 0; i < preferenceCount; i++) {
+                Preference preference = screen.getPreference(i);
+                switch (preference.getKey()) {
+                    case KEY_UNLOCK_SET_PATTERN:
+                    case KEY_UNLOCK_SET_PIN:
+                    case KEY_UNLOCK_SET_PASSWORD: {
+                        preference.setSummary(summary);
+                    } break;
+                }
+            }
+        }
+
         /**
          * Check whether the key is allowed for fallback (e.g. bio sensor). Returns true if it's
          * supported as a backup.

src/com/android/settings/accessibility/ToggleAccessibilityServicePreferenceFragment.java

@@ -36,6 +36,7 @@ import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.TextView;
 
+import com.android.internal.widget.LockPatternUtils;
 import com.android.settings.R;
 import com.android.settings.widget.ToggleSwitch;
 import com.android.settings.widget.ToggleSwitch.OnBeforeCheckedChangeListener;
@@ -201,6 +202,17 @@ public class ToggleAccessibilityServicePreferenceFragment
         View content = inflater.inflate(R.layout.enable_accessibility_service_dialog_content,
                 null);
 
+        TextView encryptionWarningView = (TextView) content.findViewById(
+                R.id.encryption_warning);
+        if (LockPatternUtils.isDeviceEncrypted()) {
+            String text = getString(R.string.enable_service_encryption_warning,
+                    info.getResolveInfo().loadLabel(getPackageManager()));
+            encryptionWarningView.setText(text);
+            encryptionWarningView.setVisibility(View.VISIBLE);
+        } else {
+            encryptionWarningView.setVisibility(View.GONE);
+        }
+
         TextView capabilitiesHeaderView = (TextView) content.findViewById(
                 R.id.capabilities_header);
         capabilitiesHeaderView.setText(getString(R.string.capabilities_list_title,