[Catalyst] Support main switch bar

MainSwitchBar is a view widget in activity layout stick to the top of
screen UI. There is no corresponding Preference in the preference
screen. For Catalyst support, introduce an invisible Preference object
to manipulate with MainSwitchBar, so that the binding mechanism is
still working on top of this abstraction.

Bug: 332201912
Flag: EXEMPT new class
Test: manual
Change-Id: If50932a443c1ed3ac04d3ea2e3273724d750297d

src/com/android/settings/SettingsActivity.java

@@ -311,6 +311,11 @@ public class SettingsActivity extends SettingsBaseActivity
         }
 
         setContentView(R.layout.settings_main_prefs);
+        mMainSwitch = findViewById(R.id.switch_bar);
+        if (mMainSwitch != null) {
+            mMainSwitch.setMetricsCategory(lookupMetricsCategory());
+            mMainSwitch.setTranslationZ(findViewById(R.id.main_content).getTranslationZ() + 1);
+        }
 
         getSupportFragmentManager().addOnBackStackChangedListener(this);
 
@@ -330,12 +335,6 @@ public class SettingsActivity extends SettingsBaseActivity
             launchSettingFragment(initialFragmentName, intent);
         }
 
-        mMainSwitch = findViewById(R.id.switch_bar);
-        if (mMainSwitch != null) {
-            mMainSwitch.setMetricsCategory(lookupMetricsCategory());
-            mMainSwitch.setTranslationZ(findViewById(R.id.main_content).getTranslationZ() + 1);
-        }
-
         // see if we should show Back/Next buttons
         if (intent.getBooleanExtra(EXTRA_PREFS_SHOW_BUTTON_BAR, false)) {
 

src/com/android/settings/widget/MainSwitchBarMetadata.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2024 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.widget
+
+import android.content.Context
+import androidx.preference.Preference
+import com.android.settingslib.metadata.PreferenceMetadata
+import com.android.settingslib.metadata.TwoStatePreference
+import com.android.settingslib.preference.PreferenceBindingPlaceholder
+import com.android.settingslib.preference.TwoStatePreferenceBinding
+
+/** Base metadata of `MainSwitchBar`. */
+interface MainSwitchBarMetadata :
+    TwoStatePreference, TwoStatePreferenceBinding, PreferenceBindingPlaceholder {
+
+    override fun createWidget(context: Context) = MainSwitchBarPreference(context, this)
+
+    override fun bind(preference: Preference, metadata: PreferenceMetadata) {
+        super.bind(preference, metadata)
+        (preference as MainSwitchBarPreference).updateVisibility()
+    }
+}

src/com/android/settings/widget/MainSwitchBarPreference.kt

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2024 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.widget
+
+import android.content.Context
+import android.widget.CompoundButton
+import android.widget.CompoundButton.OnCheckedChangeListener
+import androidx.preference.TwoStatePreference
+import com.android.settings.SettingsActivity
+import com.android.settingslib.metadata.PreferenceAvailabilityProvider
+import com.android.settingslib.widget.MainSwitchBar
+
+/** Preference abstraction of the [MainSwitchBar] in settings activity. */
+class MainSwitchBarPreference(context: Context, private val metadata: MainSwitchBarMetadata) :
+    TwoStatePreference(context), OnCheckedChangeListener {
+
+    private val mainSwitchBar: MainSwitchBar = (context as SettingsActivity).switchBar
+
+    override fun setTitle(title: CharSequence?) {
+        mainSwitchBar.setTitle(title)
+    }
+
+    override fun setSummary(summary: CharSequence?) {
+        mainSwitchBar.setSummary(summary)
+    }
+
+    override fun setEnabled(enabled: Boolean) {
+        mainSwitchBar.isEnabled = enabled
+    }
+
+    // Preference.setVisible is final, we cannot override it
+    fun updateVisibility() {
+        // always make preference invisible, the UI visibility is reflected on MainSwitchBar
+        isVisible = false
+        if ((metadata as? PreferenceAvailabilityProvider)?.isAvailable(context) != false) {
+            mainSwitchBar.show()
+        } else {
+            mainSwitchBar.hide()
+        }
+    }
+
+    override fun setChecked(checked: Boolean) {
+        // remove listener to update UI only
+        mainSwitchBar.removeOnSwitchChangeListener(this)
+        mainSwitchBar.isChecked = checked
+        mainSwitchBar.addOnSwitchChangeListener(this)
+    }
+
+    override fun onAttached() {
+        super.onAttached()
+        mainSwitchBar.addOnSwitchChangeListener(this)
+    }
+
+    override fun onCheckedChanged(buttonView: CompoundButton, isChecked: Boolean) {
+        // prevent user from toggling the switch before data store operation is done
+        isEnabled = false
+        // once data store is updated, isEnabled will be reset due to rebind
+        persistBoolean(isChecked)
+    }
+
+    override fun onDetached() {
+        mainSwitchBar.removeOnSwitchChangeListener(this)
+        super.onDetached()
+    }
+}