Add the preference controller to control accessibility button opacity preference

cherry picked from commit c497c7aabe

Bug: 173940869
Test: atest FloatingMenuOpacityPreferenceControllerTest
Change-Id: I1fbe3157c93fef4611c3b9b13569c9b339e2898a
Merged-In: I1fbe3157c93fef4611c3b9b13569c9b339e2898a

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

@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2021 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.settings.accessibility;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.database.ContentObserver;
+import android.os.Handler;
+import android.os.Looper;
+import android.provider.Settings;
+
+import androidx.annotation.VisibleForTesting;
+import androidx.preference.PreferenceScreen;
+
+import com.android.settings.core.SliderPreferenceController;
+import com.android.settings.widget.SeekBarPreference;
+import com.android.settingslib.core.lifecycle.LifecycleObserver;
+import com.android.settingslib.core.lifecycle.events.OnPause;
+import com.android.settingslib.core.lifecycle.events.OnResume;
+
+/** Preference controller that controls the opacity seekbar in accessibility button page. */
+public class FloatingMenuOpacityPreferenceController extends SliderPreferenceController
+        implements LifecycleObserver, OnResume, OnPause {
+
+    @VisibleForTesting
+    static final float DEFAULT_OPACITY = 0.55f;
+    private static final float MIN_PROGRESS = 10f;
+    private static final float MAX_PROGRESS = 100f;
+    @VisibleForTesting
+    static final float PRECISION = 100f;
+
+    private final ContentResolver mContentResolver;
+    @VisibleForTesting
+    final ContentObserver mContentObserver;
+
+    @VisibleForTesting
+    SeekBarPreference mPreference;
+
+    public FloatingMenuOpacityPreferenceController(Context context,
+            String preferenceKey) {
+        super(context, preferenceKey);
+        mContentResolver = context.getContentResolver();
+        mContentObserver = new ContentObserver(new Handler(Looper.getMainLooper())) {
+            @Override
+            public void onChange(boolean selfChange) {
+                updateAvailabilityStatus();
+            }
+        };
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AccessibilityUtil.isFloatingMenuEnabled(mContext)
+                ? AVAILABLE : DISABLED_DEPENDENT_SETTING;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+
+        mPreference = screen.findPreference(getPreferenceKey());
+        mPreference.setContinuousUpdates(true);
+        mPreference.setMax(getMax());
+        mPreference.setMin(getMin());
+        mPreference.setHapticFeedbackMode(SeekBarPreference.HAPTIC_FEEDBACK_MODE_ON_ENDS);
+
+        updateState(mPreference);
+    }
+
+    @Override
+    public void onResume() {
+        mContentResolver.registerContentObserver(
+                Settings.Secure.getUriFor(
+                        Settings.Secure.ACCESSIBILITY_BUTTON_MODE), /* notifyForDescendants= */
+                false, mContentObserver);
+
+    }
+
+    @Override
+    public void onPause() {
+        mContentResolver.unregisterContentObserver(mContentObserver);
+    }
+
+    @Override
+    public int getSliderPosition() {
+        return convertOpacityFloatToInt(getOpacity());
+    }
+
+    @Override
+    public boolean setSliderPosition(int position) {
+        final float value = convertOpacityIntToFloat(position);
+
+        return Settings.Secure.putFloat(mContentResolver,
+                Settings.Secure.ACCESSIBILITY_FLOATING_MENU_OPACITY, value);
+    }
+
+    @Override
+    public int getMax() {
+        return (int) MAX_PROGRESS;
+    }
+
+    @Override
+    public int getMin() {
+        return (int) MIN_PROGRESS;
+    }
+
+    private void updateAvailabilityStatus() {
+        mPreference.setEnabled(AccessibilityUtil.isFloatingMenuEnabled(mContext));
+    }
+
+    private int convertOpacityFloatToInt(float value) {
+        return Math.round(value * PRECISION);
+    }
+
+    private float convertOpacityIntToFloat(int value) {
+        return (float) value / PRECISION;
+    }
+
+    private float getOpacity() {
+        float value = Settings.Secure.getFloat(mContentResolver,
+                Settings.Secure.ACCESSIBILITY_FLOATING_MENU_OPACITY, DEFAULT_OPACITY);
+        final float minValue = MIN_PROGRESS / PRECISION;
+        final float maxValue = MAX_PROGRESS / PRECISION;
+
+        return (value < minValue || value > maxValue) ? DEFAULT_OPACITY : value;
+    }
+}
+