1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.settings.bluetooth; 18 19 import android.bluetooth.BluetoothAdapter; 20 import android.content.BroadcastReceiver; 21 import android.content.Context; 22 import android.content.Intent; 23 import android.content.IntentFilter; 24 25 import androidx.annotation.VisibleForTesting; 26 27 import com.android.settingslib.utils.ThreadUtils; 28 29 /** Helper class, intended to be used by an Activity, to keep the local Bluetooth adapter in 30 * discoverable mode indefinitely. By default setting the scan mode to 31 * BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE will time out after some time, but some 32 * Bluetooth settings pages would like to keep the device discoverable as long as the page is 33 * visible. */ 34 public class AlwaysDiscoverable extends BroadcastReceiver { 35 private static final String TAG = "AlwaysDiscoverable"; 36 37 private Context mContext; 38 private BluetoothAdapter mBluetoothAdapter; 39 private IntentFilter mIntentFilter; 40 41 @VisibleForTesting 42 boolean mStarted; 43 AlwaysDiscoverable(Context context)44 public AlwaysDiscoverable(Context context) { 45 mContext = context; 46 mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); 47 mIntentFilter = new IntentFilter(); 48 mIntentFilter.addAction(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED); 49 } 50 51 /** After calling start(), consumers should make a matching call to stop() when they no longer 52 * wish to enforce discoverable mode. */ start()53 public void start() { 54 if (mStarted) { 55 return; 56 } 57 mContext.registerReceiver(this, mIntentFilter, 58 Context.RECEIVER_EXPORTED_UNAUDITED); 59 mStarted = true; 60 ThreadUtils.postOnBackgroundThread(() -> { 61 if (mBluetoothAdapter.getScanMode() 62 != BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) { 63 mBluetoothAdapter.setScanMode(BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE); 64 } 65 }); 66 } 67 stop()68 public void stop() { 69 if (!mStarted) { 70 return; 71 } 72 mContext.unregisterReceiver(this); 73 mStarted = false; 74 ThreadUtils.postOnBackgroundThread( 75 () -> mBluetoothAdapter.setScanMode(BluetoothAdapter.SCAN_MODE_CONNECTABLE)); 76 } 77 78 @Override onReceive(Context context, Intent intent)79 public void onReceive(Context context, Intent intent) { 80 String action = intent.getAction(); 81 if (action != BluetoothAdapter.ACTION_SCAN_MODE_CHANGED) { 82 return; 83 } 84 ThreadUtils.postOnBackgroundThread(() -> { 85 if (mBluetoothAdapter.getScanMode() 86 != BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) { 87 mBluetoothAdapter.setScanMode(BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE); 88 } 89 }); 90 } 91 } 92