Fix the device on "Media devices" wouldn't update

- This CL use new CachedBluetoothDevice callback instance
  in construct to avoid unregister wrong callback.
- This CL use flag to make sure preference will register
  callback on onAttached() when preference remove callback
  on onPrepareForRemoval() or onDetached().
- Update test case

Bug: 168682778
Bug: 157653997
Test: make -j42 RunSettingsRoboTests
Change-Id: I7a0d9f5332153ee80634e191847b84cd7c380b7d

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

@@ -52,8 +52,7 @@ import java.lang.annotation.RetentionPolicy;
  * BluetoothDevicePreference is the preference type used to display each remote
  * Bluetooth device in the Bluetooth Settings screen.
  */
-public final class BluetoothDevicePreference extends GearPreference implements
-        CachedBluetoothDevice.Callback {
+public final class BluetoothDevicePreference extends GearPreference {
     private static final String TAG = "BluetoothDevicePref";
 
     private static int sDimAlpha = Integer.MIN_VALUE;
@@ -77,10 +76,20 @@ public final class BluetoothDevicePreference extends GearPreference implements
     private AlertDialog mDisconnectDialog;
     private String contentDescription = null;
     private boolean mHideSecondTarget = false;
+    private boolean mIsCallbackRemoved = false;
     @VisibleForTesting
     boolean mNeedNotifyHierarchyChanged = false;
     /* Talk-back descriptions for various BT icons */
     Resources mResources;
+    final BluetoothDevicePreferenceCallback mCallback;
+
+    private class BluetoothDevicePreferenceCallback implements CachedBluetoothDevice.Callback {
+
+        @Override
+        public void onDeviceAttributesChanged() {
+            onPreferenceAttributesChanged();
+        }
+    }
 
     public BluetoothDevicePreference(Context context, CachedBluetoothDevice cachedDevice,
             boolean showDeviceWithoutNames, @SortType int type) {
@@ -96,10 +105,12 @@ public final class BluetoothDevicePreference extends GearPreference implements
         }
 
         mCachedDevice = cachedDevice;
+        mCallback = new BluetoothDevicePreferenceCallback();
+        mCachedDevice.registerCallback(mCallback);
         mCurrentTime = System.currentTimeMillis();
         mType = type;
 
-        onDeviceAttributesChanged();
+        onPreferenceAttributesChanged();
     }
 
     public void setNeedNotifyHierarchyChanged(boolean needNotifyHierarchyChanged) {
@@ -126,6 +137,10 @@ public final class BluetoothDevicePreference extends GearPreference implements
     @Override
     protected void onPrepareForRemoval() {
         super.onPrepareForRemoval();
+        if (!mIsCallbackRemoved) {
+            mCachedDevice.unregisterCallback(mCallback);
+            mIsCallbackRemoved = true;
+        }
         if (mDisconnectDialog != null) {
             mDisconnectDialog.dismiss();
             mDisconnectDialog = null;
@@ -135,13 +150,20 @@ public final class BluetoothDevicePreference extends GearPreference implements
     @Override
     public void onAttached() {
         super.onAttached();
-        mCachedDevice.registerCallback(this);
+        if (mIsCallbackRemoved) {
+            mCachedDevice.registerCallback(mCallback);
+            mIsCallbackRemoved = false;
+        }
+        onPreferenceAttributesChanged();
     }
 
     @Override
     public void onDetached() {
         super.onDetached();
-        mCachedDevice.unregisterCallback(this);
+        if (!mIsCallbackRemoved) {
+            mCachedDevice.unregisterCallback(mCallback);
+            mIsCallbackRemoved = true;
+        }
     }
 
     public CachedBluetoothDevice getBluetoothDevice() {
@@ -152,7 +174,7 @@ public final class BluetoothDevicePreference extends GearPreference implements
         mHideSecondTarget = hideSecondTarget;
     }
 
-    public void onDeviceAttributesChanged() {
+    private void onPreferenceAttributesChanged() {
         /*
          * The preference framework takes care of making sure the value has
          * changed before proceeding. It will also call notifyChanged() if