Refactor Bluetooth settings for readability and performance.

Major refactoring of Bluetooth settings classes.
- Moved all functionality from LocalBluetoothManager into new
  LocalBluetoothAdapter and LocalBluetoothPreferences, and into
  existing classes.
- Refactored functionality from BluetoothEventRedirector into new
  BluetoothEventManager class, deleting the original version. New
  version uses a HashMap from action Strings to implementers of the
  BluetoothEventManager.Handler interface.
- Created new BluetoothDiscoveryReceiver to update shared preferences
  timestamp for Bluetooth discovery start/finish. This is the only event
  handling we need to do when the settings app is not visible, so it has
  its own receiver entry in AndroidManifest.xml. Edits are written using
  QueuedWork.singleThreadExecutor(), which BroadcastReceiver knows about
  and will wait for completion, eliminating the need for PendingResult.
- Miscellaneous cleanups to code style and logic for readability.
- Pulled some large switch statement code blocks into new methods.
- Changed all Bluetooth state references to the new BluetoothProfile
  constants.
- Changed use of deprecated Notification constructor in
  BluetoothPairingRequest to use Notification.Builder.
- Moved Utf8ByteLengthFilter helper function from BluetoothNamePreference
  into its own class, and moved test cases into the same package.
- Moved all LocalBluetoothProfileManager functionality related to
  specific profiles into new top-level classes (A2dpProfile, etc.), all
  implementing the LocalBluetoothProfile interface.
- Moved all UI-related methods from CachedBluetoothDevice into the class
  that uses the method, or into the static Utils class for shared methods.

Change-Id: I6d49b7f4ae0c7d7dcf62551ee40b51ecb5fe4f47

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

@@ -0,0 +1,216 @@
+/*
+ * Copyright (C) 2011 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.bluetooth;
+
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothProfile;
+import android.content.Context;
+import android.os.ParcelUuid;
+import android.util.Log;
+
+import java.util.Set;
+
+/**
+ * LocalBluetoothAdapter provides an interface between the Settings app
+ * and the functionality of the local {@link BluetoothAdapter}, specifically
+ * those related to state transitions of the adapter itself.
+ *
+ * <p>Connection and bonding state changes affecting specific devices
+ * are handled by {@link CachedBluetoothDeviceManager},
+ * {@link BluetoothEventManager}, and {@link LocalBluetoothProfileManager}.
+ */
+public final class LocalBluetoothAdapter {
+    private static final String TAG = "LocalBluetoothAdapter";
+
+    /** This class does not allow direct access to the BluetoothAdapter. */
+    private final BluetoothAdapter mAdapter;
+
+    private LocalBluetoothProfileManager mProfileManager;
+
+    private static LocalBluetoothAdapter sInstance;
+
+    private int mState = BluetoothAdapter.ERROR;
+
+    private static final int SCAN_EXPIRATION_MS = 5 * 60 * 1000; // 5 mins
+
+    private long mLastScan;
+
+    private LocalBluetoothAdapter(BluetoothAdapter adapter) {
+        mAdapter = adapter;
+    }
+
+    void setProfileManager(LocalBluetoothProfileManager manager) {
+        mProfileManager = manager;
+    }
+
+    /**
+     * Get the singleton instance of the LocalBluetoothAdapter. If this device
+     * doesn't support Bluetooth, then null will be returned. Callers must be
+     * prepared to handle a null return value.
+     * @return the LocalBluetoothAdapter object, or null if not supported
+     */
+    static synchronized LocalBluetoothAdapter getInstance() {
+        if (sInstance == null) {
+            BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
+            if (adapter != null) {
+                sInstance = new LocalBluetoothAdapter(adapter);
+            }
+        }
+
+        return sInstance;
+    }
+
+    // Pass-through BluetoothAdapter methods that we can intercept if necessary
+
+    void cancelDiscovery() {
+        mAdapter.cancelDiscovery();
+    }
+
+    boolean enable() {
+        return mAdapter.enable();
+    }
+
+    boolean disable() {
+        return mAdapter.disable();
+    }
+
+    void getProfileProxy(Context context,
+            BluetoothProfile.ServiceListener listener, int profile) {
+        mAdapter.getProfileProxy(context, listener, profile);
+    }
+
+    Set<BluetoothDevice> getBondedDevices() {
+        return mAdapter.getBondedDevices();
+    }
+
+    String getName() {
+        return mAdapter.getName();
+    }
+
+    int getScanMode() {
+        return mAdapter.getScanMode();
+    }
+
+    int getState() {
+        return mAdapter.getState();
+    }
+
+    ParcelUuid[] getUuids() {
+        return mAdapter.getUuids();
+    }
+
+    boolean isDiscovering() {
+        return mAdapter.isDiscovering();
+    }
+
+    boolean isEnabled() {
+        return mAdapter.isEnabled();
+    }
+
+    void setDiscoverableTimeout(int timeout) {
+        mAdapter.setDiscoverableTimeout(timeout);
+    }
+
+    void setName(String name) {
+        mAdapter.setName(name);
+    }
+
+    void setScanMode(int mode) {
+        mAdapter.setScanMode(mode);
+    }
+
+    boolean setScanMode(int mode, int duration) {
+        return mAdapter.setScanMode(mode, duration);
+    }
+
+    void startScanning(boolean force) {
+        // Only start if we're not already scanning
+        if (!mAdapter.isDiscovering()) {
+            if (!force) {
+                // Don't scan more than frequently than SCAN_EXPIRATION_MS,
+                // unless forced
+                if (mLastScan + SCAN_EXPIRATION_MS > System.currentTimeMillis()) {
+                    return;
+                }
+
+                // If we are playing music, don't scan unless forced.
+                A2dpProfile a2dp = mProfileManager.getA2dpProfile();
+                if (a2dp != null && a2dp.isA2dpPlaying()) {
+                    return;
+                }
+            }
+
+            if (mAdapter.startDiscovery()) {
+                mLastScan = System.currentTimeMillis();
+            }
+        }
+    }
+
+    void stopScanning() {
+        if (mAdapter.isDiscovering()) {
+            mAdapter.cancelDiscovery();
+        }
+    }
+
+    public synchronized int getBluetoothState() {
+        // Always sync state, in case it changed while paused
+        syncBluetoothState();
+        return mState;
+    }
+
+    synchronized void setBluetoothStateInt(int state) {
+        mState = state;
+
+        if (state == BluetoothAdapter.STATE_ON) {
+            // if mProfileManager hasn't been constructed yet, it will
+            // get the adapter UUIDs in its constructor when it is.
+            if (mProfileManager != null) {
+                mProfileManager.setBluetoothStateOn();
+            }
+        }
+    }
+
+    // Returns true if the state changed; false otherwise.
+    boolean syncBluetoothState() {
+        int currentState = mAdapter.getState();
+        if (currentState != mState) {
+            setBluetoothStateInt(mAdapter.getState());
+            return true;
+        }
+        return false;
+    }
+
+    public void setBluetoothEnabled(boolean enabled) {
+        boolean success = enabled
+                ? mAdapter.enable()
+                : mAdapter.disable();
+
+        if (success) {
+            setBluetoothStateInt(enabled
+                ? BluetoothAdapter.STATE_TURNING_ON
+                : BluetoothAdapter.STATE_TURNING_OFF);
+        } else {
+            if (Utils.V) {
+                Log.v(TAG, "setBluetoothEnabled call, manager didn't return " +
+                        "success for enabled: " + enabled);
+            }
+
+            syncBluetoothState();
+        }
+    }
+}