Make device discoverable in Connected Devices settings page

* For fix the TreeHugger error in pi-dev, cherry pick the ag/4042235 in
  master and fix TreeHugger error. Change android.support.v7.* to androidx.*
* Set preference title by bluetooth state
* Enable bluetooth discoverable mode in Connected device page
* Add more test cases for DiscoverableFooterPreferenceController

Bug: 79294219
Test: make -j50 RunSettingsRoboTests
Change-Id: I6d4f8ec3870c43bf48e9666eabd60068aa8950bb

src/com/android/settings/connecteddevice/DiscoverableFooterPreferenceController.java

@@ -16,35 +16,79 @@
 
 package com.android.settings.connecteddevice;
 
+import android.bluetooth.BluetoothAdapter;
+import android.content.BroadcastReceiver;
 import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
 import android.content.pm.PackageManager;
+import android.text.BidiFormatter;
+import android.text.TextUtils;
 import androidx.annotation.VisibleForTesting;
 import androidx.preference.PreferenceScreen;
+
+import com.android.settings.bluetooth.AlwaysDiscoverable;
+import com.android.settings.bluetooth.Utils;
 import com.android.settings.core.BasePreferenceController;
 import com.android.settings.dashboard.DashboardFragment;
+import com.android.settings.R;
+import com.android.settingslib.bluetooth.LocalBluetoothAdapter;
+import com.android.settingslib.bluetooth.LocalBluetoothManager;
+import com.android.settingslib.core.lifecycle.events.OnPause;
+import com.android.settingslib.core.lifecycle.events.OnResume;
+import com.android.settingslib.core.lifecycle.LifecycleObserver;
 import com.android.settingslib.widget.FooterPreference;
 import com.android.settingslib.widget.FooterPreferenceMixin;
 
 /**
  * Controller that shows and updates the bluetooth device name
  */
-public class DiscoverableFooterPreferenceController extends BasePreferenceController {
+public class DiscoverableFooterPreferenceController extends BasePreferenceController
+        implements LifecycleObserver, OnResume, OnPause {
     private static final String KEY = "discoverable_footer_preference";
 
-    private FooterPreference mPreference;
+    @VisibleForTesting
+    BroadcastReceiver mBluetoothChangedReceiver;
     private FooterPreferenceMixin mFooterPreferenceMixin;
+    private FooterPreference mPreference;
+    private LocalBluetoothManager mLocalManager;
+    private LocalBluetoothAdapter mLocalAdapter;
+    private AlwaysDiscoverable mAlwaysDiscoverable;
 
+    public DiscoverableFooterPreferenceController(Context context) {
+        super(context, KEY);
+        mLocalManager = Utils.getLocalBtManager(context);
+        if (mLocalManager == null) {
+            return;
+        }
+        mLocalAdapter = mLocalManager.getBluetoothAdapter();
+        mAlwaysDiscoverable = new AlwaysDiscoverable(context, mLocalAdapter);
+        initReceiver();
+    }
 
-    public DiscoverableFooterPreferenceController(Context context) { super(context, KEY); }
+    private void initReceiver() {
+        mBluetoothChangedReceiver = new BroadcastReceiver() {
+            @Override
+            public void onReceive(Context context, Intent intent) {
+                if (intent.getAction().equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
+                    final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,
+                            BluetoothAdapter.ERROR);
+                    updateFooterPreferenceTitle(state);
+                }
+            }
+        };
+    }
 
     public void init(DashboardFragment fragment) {
         mFooterPreferenceMixin = new FooterPreferenceMixin(fragment, fragment.getLifecycle());
     }
 
     @VisibleForTesting
-    void init(FooterPreferenceMixin footerPreferenceMixin, FooterPreference preference) {
+    void init(FooterPreferenceMixin footerPreferenceMixin, FooterPreference preference,
+            AlwaysDiscoverable alwaysDiscoverable) {
         mFooterPreferenceMixin = footerPreferenceMixin;
         mPreference = preference;
+        mAlwaysDiscoverable = alwaysDiscoverable;
     }
 
     @Override
@@ -65,4 +109,37 @@ public class DiscoverableFooterPreferenceController extends BasePreferenceContro
         mPreference.setKey(KEY);
         screen.addPreference(mPreference);
     }
+
+    @Override
+    public void onResume() {
+        mContext.registerReceiver(mBluetoothChangedReceiver,
+                new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED));
+        mAlwaysDiscoverable.start();
+        updateFooterPreferenceTitle(mLocalAdapter.getState());
+    }
+
+    @Override
+    public void onPause() {
+        mContext.unregisterReceiver(mBluetoothChangedReceiver);
+        mAlwaysDiscoverable.stop();
+    }
+
+    private void updateFooterPreferenceTitle (int bluetoothState) {
+        if (bluetoothState == BluetoothAdapter.STATE_ON) {
+            mPreference.setTitle(getPreferenceTitle());
+        } else {
+            mPreference.setTitle(R.string.bluetooth_off_footer);
+        }
+    }
+
+    private CharSequence getPreferenceTitle() {
+        final String deviceName = mLocalAdapter.getName();
+        if (TextUtils.isEmpty(deviceName)) {
+            return null;
+        }
+
+        return TextUtils.expandTemplate(
+                mContext.getText(R.string.bluetooth_device_name_summary),
+                BidiFormatter.getInstance().unicodeWrap(deviceName));
+    }
 }