Adding feature flag and replace existing boolean with settings check

Test: Locally tested + AccessibilityUserStateTest
Bug: 282039824

Change-Id: I1706629c7505e396d8a13981488bc7b52186ef2a
diff --git a/services/accessibility/accessibility.aconfig b/services/accessibility/accessibility.aconfig
index a754ba5..997f3af 100644
--- a/services/accessibility/accessibility.aconfig
+++ b/services/accessibility/accessibility.aconfig
@@ -59,6 +59,13 @@
 }
 
 flag {
+    name: "enable_magnification_one_finger_panning_gesture"
+    namespace: "accessibility"
+    description: "Whether to allow easy-mode (one finger panning gesture) for magnification"
+    bug: "282039824"
+}
+
+flag {
     name: "fix_drag_pointer_when_ending_drag"
     namespace: "accessibility"
     description: "Send the correct pointer id when transitioning from dragging to delegating states."
diff --git a/services/accessibility/java/com/android/server/accessibility/magnification/FullScreenMagnificationGestureHandler.java b/services/accessibility/java/com/android/server/accessibility/magnification/FullScreenMagnificationGestureHandler.java
index 279bd72..6d1ab9f 100644
--- a/services/accessibility/java/com/android/server/accessibility/magnification/FullScreenMagnificationGestureHandler.java
+++ b/services/accessibility/java/com/android/server/accessibility/magnification/FullScreenMagnificationGestureHandler.java
@@ -167,7 +167,7 @@
     })
     public @interface OverscrollState {}
 
-    @VisibleForTesting boolean mIsSinglePanningEnabled;
+    @VisibleForTesting final OneFingerPanningSettingsProvider mOneFingerPanningSettingsProvider;
 
     private final FullScreenMagnificationVibrationHelper mFullScreenMagnificationVibrationHelper;
 
@@ -201,7 +201,11 @@
                 displayId,
                 fullScreenMagnificationVibrationHelper,
                 /* magnificationLogger= */ null,
-                ViewConfiguration.get(context));
+                ViewConfiguration.get(context),
+                new OneFingerPanningSettingsProvider(
+                        context,
+                        Flags.enableMagnificationOneFingerPanningGesture()
+                ));
     }
 
     /** Constructor for tests. */
@@ -218,7 +222,9 @@
             int displayId,
             FullScreenMagnificationVibrationHelper fullScreenMagnificationVibrationHelper,
             MagnificationLogger magnificationLogger,
-            ViewConfiguration viewConfiguration) {
+            ViewConfiguration viewConfiguration,
+            OneFingerPanningSettingsProvider oneFingerPanningSettingsProvider
+    ) {
         super(displayId, detectSingleFingerTripleTap, detectTwoFingerTripleTap,
                 detectShortcutTrigger, trace, callback);
         if (DEBUG_ALL) {
@@ -301,9 +307,7 @@
         mPanningScalingState = new PanningScalingState(context);
         mSinglePanningState = new SinglePanningState(context);
         mFullScreenMagnificationVibrationHelper = fullScreenMagnificationVibrationHelper;
-        setSinglePanningEnabled(
-                context.getResources()
-                        .getBoolean(R.bool.config_enable_a11y_magnification_single_panning));
+        mOneFingerPanningSettingsProvider = oneFingerPanningSettingsProvider;
         mOverscrollHandler = new OverscrollHandler();
         mIsWatch = context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_WATCH);
 
@@ -317,11 +321,6 @@
         transitionTo(mDetectingState);
     }
 
-    @VisibleForTesting
-    void setSinglePanningEnabled(boolean isEnabled) {
-        mIsSinglePanningEnabled = isEnabled;
-    }
-
     @Override
     void onMotionEventInternal(MotionEvent event, MotionEvent rawEvent, int policyFlags) {
         if (event.getActionMasked() == ACTION_DOWN) {
@@ -361,6 +360,7 @@
             Slog.i(mLogTag, "onDestroy(); delayed = "
                     + MotionEventInfo.toString(mDetectingState.mDelayedEventQueue));
         }
+        mOneFingerPanningSettingsProvider.unregister();
 
         if (mScreenStateReceiver != null) {
             mScreenStateReceiver.unregister();
@@ -524,7 +524,7 @@
                     && event.getPointerCount() == 2 // includes the pointer currently being released
                     && mPreviousState == mViewportDraggingState) {
                 // if feature flag is enabled, currently only true on watches
-                if (mIsSinglePanningEnabled) {
+                if (mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()) {
                     mOverscrollHandler.setScaleAndCenterToEdgeIfNeeded();
                     mOverscrollHandler.clearEdgeState();
                 }
@@ -532,7 +532,7 @@
             } else if (action == ACTION_UP || action == ACTION_CANCEL) {
                 onPanningFinished(event);
                 // if feature flag is enabled, currently only true on watches
-                if (mIsSinglePanningEnabled) {
+                if (mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()) {
                     mOverscrollHandler.setScaleAndCenterToEdgeIfNeeded();
                     mOverscrollHandler.clearEdgeState();
                 }
@@ -611,7 +611,7 @@
             onPan(second);
             mFullScreenMagnificationController.offsetMagnifiedRegion(mDisplayId, distanceX,
                     distanceY, AccessibilityManagerService.MAGNIFICATION_GESTURE_HANDLER_ID);
-            if (mIsSinglePanningEnabled) {
+            if (mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()) {
                 mOverscrollHandler.onScrollStateChanged(first, second);
             }
             return /* event consumed: */ true;
@@ -1000,7 +1000,7 @@
                                 && event.getPointerCount() == 2) {
                             transitionToViewportDraggingStateAndClear(event);
                         } else if (isActivated() && event.getPointerCount() == 2) {
-                            if (mIsSinglePanningEnabled
+                            if (mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()
                                     && overscrollState(event, mFirstPointerDownLocation)
                                     == OVERSCROLL_VERTICAL_EDGE) {
                                 transitionToDelegatingStateAndClear();
@@ -1008,7 +1008,7 @@
                                 //Primary pointer is swiping, so transit to PanningScalingState
                                 transitToPanningScalingStateAndClear();
                             }
-                        } else if (mIsSinglePanningEnabled
+                        } else if (mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()
                                 && isActivated()
                                 && event.getPointerCount() == 1) {
                             if (overscrollState(event, mFirstPointerDownLocation)
@@ -1255,7 +1255,7 @@
                         if (isMultiTapTriggered(2 /* taps */) && event.getPointerCount() == 1) {
                             transitionToViewportDraggingStateAndClear(event);
                         } else if (isActivated() && event.getPointerCount() == 2) {
-                            if (mIsSinglePanningEnabled
+                            if (mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()
                                     && overscrollState(event, mFirstPointerDownLocation)
                                     == OVERSCROLL_VERTICAL_EDGE) {
                                 transitionToDelegatingStateAndClear();
@@ -1263,7 +1263,7 @@
                                 //Primary pointer is swiping, so transit to PanningScalingState
                                 transitToPanningScalingStateAndClear();
                             }
-                        } else if (mIsSinglePanningEnabled
+                        } else if (mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()
                                 && isActivated()
                                 && event.getPointerCount() == 1) {
                             if (overscrollState(event, mFirstPointerDownLocation)
@@ -1633,7 +1633,8 @@
                 + ", mPreviousState=" + State.nameOf(mPreviousState)
                 + ", mMagnificationController=" + mFullScreenMagnificationController
                 + ", mDisplayId=" + mDisplayId
-                + ", mIsSinglePanningEnabled=" + mIsSinglePanningEnabled
+                + ", mIsSinglePanningEnabled="
+                + mOneFingerPanningSettingsProvider.isOneFingerPanningEnabled()
                 + ", mOverscrollHandler=" + mOverscrollHandler
                 + '}';
     }
diff --git a/services/accessibility/java/com/android/server/accessibility/magnification/OneFingerPanningSettingsProvider.java b/services/accessibility/java/com/android/server/accessibility/magnification/OneFingerPanningSettingsProvider.java
new file mode 100644
index 0000000..3cdaf98
--- /dev/null
+++ b/services/accessibility/java/com/android/server/accessibility/magnification/OneFingerPanningSettingsProvider.java
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.server.accessibility.magnification;
+
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.res.Resources;
+import android.database.ContentObserver;
+import android.net.Uri;
+import android.provider.Settings;
+
+import androidx.annotation.VisibleForTesting;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Provider for secure settings {@link Settings.Secure.ACCESSIBILITY_SINGLE_FINGER_PANNING_ENABLED}.
+ */
+public class OneFingerPanningSettingsProvider {
+
+    @VisibleForTesting
+    static final String KEY = Settings.Secure.ACCESSIBILITY_SINGLE_FINGER_PANNING_ENABLED;
+    private static final Uri URI = Settings.Secure.getUriFor(KEY);
+    private AtomicBoolean mCached = new AtomicBoolean();
+    @VisibleForTesting
+    ContentObserver mObserver;
+    @VisibleForTesting
+    ContentResolver mContentResolver;
+
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface State {
+        int OFF = 0;
+        int ON = 1;
+    }
+
+    public OneFingerPanningSettingsProvider(
+            Context context,
+            boolean featureFlagEnabled
+    ) {
+        var defaultValue = isOneFingerPanningEnabledDefault(context);
+        if (featureFlagEnabled) {
+            mContentResolver = context.getContentResolver();
+            mObserver = new ContentObserver(context.getMainThreadHandler()) {
+                @Override
+                public void onChange(boolean selfChange) {
+                    mCached.set(isOneFingerPanningEnabledInSetting(context, defaultValue));
+                }
+            };
+            mCached.set(isOneFingerPanningEnabledInSetting(context, defaultValue));
+            mContentResolver.registerContentObserver(URI, false, mObserver);
+        } else {
+            mCached.set(defaultValue);
+        }
+    }
+
+    /** Returns whether one finger panning is enabled.. */
+    public boolean isOneFingerPanningEnabled() {
+        return mCached.get();
+    }
+
+    /** Unregister content observer for listening to secure settings. */
+    public void unregister() {
+        if (mContentResolver != null) {
+            mContentResolver.unregisterContentObserver(mObserver);
+        }
+        mContentResolver = null;
+    }
+
+    private boolean isOneFingerPanningEnabledInSetting(Context context, boolean defaultValue) {
+        return State.ON == Settings.Secure.getIntForUser(
+                mContentResolver,
+                KEY,
+                (defaultValue ? State.ON : State.OFF),
+                context.getUserId());
+    }
+
+    @VisibleForTesting
+    static boolean isOneFingerPanningEnabledDefault(Context context) {
+        boolean oneFingerPanningDefaultValue;
+        try {
+            oneFingerPanningDefaultValue = context.getResources().getBoolean(
+                    com.android.internal.R.bool.config_enable_a11y_magnification_single_panning);
+        } catch (Resources.NotFoundException e) {
+            oneFingerPanningDefaultValue = false;
+        }
+        return oneFingerPanningDefaultValue;
+    }
+}