Fix transparency seekbar in accessibility button page is backwards

Root Cause: Store value in opacity value, need to be inverted to
transparency value.

Solution: transfer to transparency value and rename related field.

Bug: 183980065
Test: atest FloatingMenuTransparencyPreferenceControllerTest
Change-Id: I763dda47854e7cf945a95f4a7d4965725cd73824

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

@@ -0,0 +1,153 @@
+/*
+ * 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.FloatRange;
+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 transparency seekbar in accessibility button page. */
+public class FloatingMenuTransparencyPreferenceController extends SliderPreferenceController
+        implements LifecycleObserver, OnResume, OnPause {
+
+    @VisibleForTesting
+    @FloatRange(from = 0.0, to = 1.0)
+    static final float DEFAULT_TRANSPARENCY = 0.45f;
+    @VisibleForTesting
+    static final float MAXIMUM_TRANSPARENCY = 1.0f;
+    private static final int FADE_ENABLED = 1;
+    private static final float MIN_PROGRESS = 0f;
+    private static final float MAX_PROGRESS = 90f;
+    @VisibleForTesting
+    static final float PRECISION = 100f;
+
+    private final ContentResolver mContentResolver;
+    @VisibleForTesting
+    final ContentObserver mContentObserver;
+
+    @VisibleForTesting
+    SeekBarPreference mPreference;
+
+    public FloatingMenuTransparencyPreferenceController(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);
+        mContentResolver.registerContentObserver(
+                Settings.Secure.getUriFor(
+                        Settings.Secure.ACCESSIBILITY_FLOATING_MENU_FADE_ENABLED),
+                        /* notifyForDescendants= */ false, mContentObserver);
+    }
+
+    @Override
+    public void onPause() {
+        mContentResolver.unregisterContentObserver(mContentObserver);
+    }
+
+    @Override
+    public int getSliderPosition() {
+        return convertTransparencyFloatToInt(getTransparency());
+    }
+
+    @Override
+    public boolean setSliderPosition(int position) {
+        final float opacityValue = MAXIMUM_TRANSPARENCY - convertTransparencyIntToFloat(position);
+        return Settings.Secure.putFloat(mContentResolver,
+                Settings.Secure.ACCESSIBILITY_FLOATING_MENU_OPACITY, opacityValue);
+    }
+
+    @Override
+    public int getMax() {
+        return (int) MAX_PROGRESS;
+    }
+
+    @Override
+    public int getMin() {
+        return (int) MIN_PROGRESS;
+    }
+
+    private void updateAvailabilityStatus() {
+        final boolean fadeEnabled = Settings.Secure.getInt(mContentResolver,
+                Settings.Secure.ACCESSIBILITY_FLOATING_MENU_FADE_ENABLED, FADE_ENABLED)
+                == FADE_ENABLED;
+
+        mPreference.setEnabled(AccessibilityUtil.isFloatingMenuEnabled(mContext) && fadeEnabled);
+    }
+
+    private int convertTransparencyFloatToInt(float value) {
+        return Math.round(value * PRECISION);
+    }
+
+    private float convertTransparencyIntToFloat(int value) {
+        return (float) value / PRECISION;
+    }
+
+    private float getTransparency() {
+        float transparencyValue = MAXIMUM_TRANSPARENCY - (Settings.Secure.getFloat(mContentResolver,
+                Settings.Secure.ACCESSIBILITY_FLOATING_MENU_OPACITY, DEFAULT_TRANSPARENCY));
+        final float minValue = MIN_PROGRESS / PRECISION;
+        final float maxValue = MAX_PROGRESS / PRECISION;
+
+        return (transparencyValue < minValue || transparencyValue > maxValue)
+                ? DEFAULT_TRANSPARENCY : transparencyValue;
+    }
+}