Bluetooth: Only show devices when their names are resolved

* Add a developer menu option to allow name-less devices to be shown
  when a Bluetooth developer needs it, but hide it for non-developer
  users.
* Set BluetoothDevicePreference to invisible when CachedBluetoothDevice
  does not have a name besides MAC address and the above developer option
  is false.
* This affects BluetoothPairingDetail and DevicePickerFragment, but does
  not affect BluetoothSettings. BluetoothSettings will show all paired
  devices regardless whether an user friendly name exists.

Bug: 34685932
Test: pair Bluetooth device, send file over Bluetooth, unit tests
Change-Id: Idd7ad4b1671dfdcf3204efb50eddb6dae1065aa5

src/com/android/settings/bluetooth/BluetoothDevicePreference.java

@@ -54,16 +54,17 @@ public final class BluetoothDevicePreference extends GearPreference implements
     private final UserManager mUserManager;
 
     private AlertDialog mDisconnectDialog;
-
     private String contentDescription = null;
-
+    private DeviceListPreferenceFragment mDeviceListPreferenceFragment;
     /* Talk-back descriptions for various BT icons */
     Resources mResources;
 
-    public BluetoothDevicePreference(Context context, CachedBluetoothDevice cachedDevice) {
+    public BluetoothDevicePreference(Context context, CachedBluetoothDevice cachedDevice,
+            DeviceListPreferenceFragment deviceListPreferenceFragment) {
         super(context, null);
         mResources = getContext().getResources();
         mUserManager = (UserManager) context.getSystemService(Context.USER_SERVICE);
+        mDeviceListPreferenceFragment = deviceListPreferenceFragment;
 
         if (sDimAlpha == Integer.MIN_VALUE) {
             TypedValue outValue = new TypedValue();
@@ -131,6 +132,11 @@ public final class BluetoothDevicePreference extends GearPreference implements
         // Used to gray out the item
         setEnabled(!mCachedDevice.isBusy());
 
+        // Device is only visible in the UI if it has a valid name besides MAC address or when user
+        // allows showing devices without user-friendly name in developer settings
+        setVisible(mDeviceListPreferenceFragment.shouldShowDevicesWithoutNames()
+                || mCachedDevice.hasHumanReadableName());
+
         // This could affect ordering, so notify that
         notifyHierarchyChanged();
     }

src/com/android/settings/bluetooth/BluetoothSettings.java

@@ -140,6 +140,8 @@ public class BluetoothSettings extends DeviceListPreferenceFragment implements I
             mBluetoothEnabler.resume(getActivity());
         }
         super.onStart();
+        // Always show paired devices regardless whether user-friendly name exists
+        mShowDevicesWithoutNames = true;
         if (isUiRestricted()) {
             getPreferenceScreen().removeAll();
             if (!isUiRestrictedByOnlyAdmin()) {

src/com/android/settings/bluetooth/DeviceListPreferenceFragment.java

@@ -19,6 +19,7 @@ package com.android.settings.bluetooth;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 import android.os.Bundle;
+import android.os.SystemProperties;
 import android.support.annotation.VisibleForTesting;
 import android.support.v7.preference.Preference;
 import android.support.v7.preference.PreferenceCategory;
@@ -52,6 +53,10 @@ public abstract class DeviceListPreferenceFragment extends
 
     private static final String KEY_BT_SCAN = "bt_scan";
 
+    // Copied from DevelopmentSettings.java
+    private static final String BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY =
+            "persist.bluetooth.showdeviceswithoutnames";
+
     private BluetoothDeviceFilter.Filter mFilter;
 
     @VisibleForTesting
@@ -68,6 +73,8 @@ public abstract class DeviceListPreferenceFragment extends
     final WeakHashMap<CachedBluetoothDevice, BluetoothDevicePreference> mDevicePreferenceMap =
             new WeakHashMap<CachedBluetoothDevice, BluetoothDevicePreference>();
 
+    boolean mShowDevicesWithoutNames;
+
     DeviceListPreferenceFragment(String restrictedKey) {
         super(restrictedKey);
         mFilter = BluetoothDeviceFilter.ALL_FILTER;
@@ -103,6 +110,8 @@ public abstract class DeviceListPreferenceFragment extends
     @Override
     public void onStart() {
         super.onStart();
+        mShowDevicesWithoutNames = SystemProperties.getBoolean(
+                BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY, false);
         if (mLocalManager == null || isUiRestricted()) return;
 
         mLocalManager.setForegroundActivity(getActivity());
@@ -181,7 +190,7 @@ public abstract class DeviceListPreferenceFragment extends
         BluetoothDevicePreference preference = (BluetoothDevicePreference) getCachedPreference(key);
 
         if (preference == null) {
-            preference = new BluetoothDevicePreference(getPrefContext(), cachedDevice);
+            preference = new BluetoothDevicePreference(getPrefContext(), cachedDevice, this);
             preference.setKey(key);
             mDeviceListGroup.addPreference(preference);
         } else {
@@ -271,4 +280,8 @@ public abstract class DeviceListPreferenceFragment extends
      * Return the key of the {@link PreferenceGroup} that contains the bluetooth devices
      */
     public abstract String getDeviceListKey();
+
+    public boolean shouldShowDevicesWithoutNames() {
+        return mShowDevicesWithoutNames;
+    }
 }