一、前言
截止到本文完成的日期为止（2020年04月16日），笔者对Android 5.0~Android 10的部分手机进行了适配测试。该文中所遇到的问题基本都出现在国产定制系统（EMUI、MIUI、ColorOS）上。开发环境为macOS+idea。
二、相关代码
- 1、（基本）在AndroidManifest.xml中静态申请如下权限：
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />
<uses-feature
android:name="android.hardware.bluetooth_le"
android:required="true" />*BLE的扫描需要开启位置信息相关的权限，否则将会无法扫描到BLE设备。
*在MIUI11（Android 10）中，需要另行打开位置服务（GPS），否则也不能扫描到BLE设备。部分其它国产ROM在Android 10也可能存在此问题，解决办法同上。判断标准是：BluetoothLeScanner被正确地实例化（不为null），但始终无法发现附近的BLE设备。
- 2、（Android 6.0及以上）在onCreate中动态申请位置信息权限：
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.M) {
Log.i(TAG, "sdk < Android M");
if (ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
|| ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
String[] strings =
{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION};
ActivityCompat.requestPermissions(this, strings, 1);
}
} else {
if (ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
|| ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
|| ActivityCompat.checkSelfPermission(this,
"android.permission.ACCESS_BACKGROUND_LOCATION") != PackageManager.PERMISSION_GRANTED) {
String[] strings = {android.Manifest.permission.ACCESS_FINE_LOCATION,
android.Manifest.permission.ACCESS_COARSE_LOCATION,
"android.permission.ACCESS_BACKGROUND_LOCATION"};
ActivityCompat.requestPermissions(this, strings, 2);
}
}检测是否打开位置服务：
public static final boolean isLocationEnable(Context context) {
LocationManager locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
boolean networkProvider = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
boolean gpsProvider = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
if (networkProvider || gpsProvider) return true;
return false;
}如果未打开位置服务，让用户去打开：
private static final int REQUEST_CODE_LOCATION_SETTINGS = 2;
private void setLocationService() {
Intent locationIntent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
this.startActivityForResult(locationIntent, REQUEST_CODE_LOCATION_SETTINGS);
}进入设置，让用户自己选择是否打开位置服务，然后获取选择结果：
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE_LOCATION_SETTINGS) {
if (isLocationEnable(this)) {
//定位已打开的处理
} else {
//定位依然没有打开的处理
}
} else super.onActivityResult(requestCode, resultCode, data);
}- 3、（基本）检测是否支持BLE蓝牙及蓝牙开关状态
//是否支持
public static boolean isSupportBle(Context context) {
if (context == null || !context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
return false;
}
BluetoothManager manager = (BluetoothManager) context.getSystemService(Context.BLUETOOTH_SERVICE);
return manager.getAdapter() != null;
}
//是否开启
public static boolean isBleEnable(Context context) {
if (!isSupportBle(context)) {
return false;
}
BluetoothManager manager = (BluetoothManager) context.getSystemService(Context.BLUETOOTH_SERVICE);
return manager.getAdapter().isEnabled();
}
//开启蓝牙
public static void enableBluetooth(Activity activity, int requestCode) {
Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
activity.startActivityForResult(intent, requestCode);
}- 4、（基本&&Android 7.0+适配特别注意！）进行BLE设备扫描
在Android 7.0及以后的系统中，BluetoothAdapter.startLeScan()方法被废弃，所以需要根据系统版本的不同来执行不同的扫描方法，否则在MIUI11及EMUI10的部分机型上会扫描不到BLE设备。
private void startScan() throws Exception {
isScanning = true;
handler.postDelayed(scanRunnable, TIME_OUT);
BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.M) {
LogUtil.e("系统版本：","<7.0");
bluetoothManager.getAdapter()
.startLeScan(mLeScanCallback);
} else {//安卓7.0及以上的方案
LogUtil.e("系统版本：",">=7.0");
bleScanner = bluetoothManager.getAdapter().getBluetoothLeScanner();
bleScanner.startScan(scanCallback);
}
}//停止扫描
private void stopScan() {
isScanning = false;
BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.M) {
//安卓6.0及以下版本BLE操作的代码
bluetoothManager.getAdapter().stopLeScan(mLeScanCallback);
} else
//安卓7.0及以上版本BLE操作的代码
bleScanner.stopScan(scanCallback);
}//扫描结果回调-Android 7.0-
private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {
@SuppressLint("HandlerLeak")
@Override
public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {
LogUtil.e(TAG, "开始搜索设备：" + mac);
if (device.getAddress().equals(mac)) {
LogUtil.e(TAG, "搜索到设备 " + mac);
new Handler() {
@Override
public void handleMessage(Message msg) {
if (mBluetoothLeService != null) {
mBluetoothLeService.connect(mac);
}
}
}.sendEmptyMessageDelayed(3000, 200);
stopScan();
isScanning = false;
handler.removeCallbacks(scanRunnable);
}
}
};
//扫描结果回调-7.0+
private ScanCallback scanCallback = new ScanCallback() {
@SuppressLint("HandlerLeak")
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
@Override
public void onScanResult(int callbackType, ScanResult result) {
super.onScanResult(callbackType, result);
BluetoothDevice device = result.getDevice();
String macAddr = device.getAddress();
LogUtil.e("发现设备：", macAddr);
if (macAddr.equals(mac)) {
LogUtil.e(TAG, "搜索到匹配的蓝牙设备(6.0+): " + mac);
new Handler() {
@Override
public void handleMessage(Message msg) {
if (mBluetoothLeService != null) {
mBluetoothLeService.connect(mac);
}
}
}.sendEmptyMessageDelayed(3000, 200);
stopScan();
isScanning = false;
handler.removeCallbacks(scanRunnable);
}
Log.i(TAG, macAddr);
}
};//重连计时器
private Runnable scanRunnable = new Runnable() {
@Override
public void run() {
connTimeOutTimes++;
LogUtil.e(TAG, "重连第" + connTimeOutTimes + "次");
if (connTimeOutTimes < RECONNECT_TIMES) {
handler.postDelayed(scanRunnable, TIME_OUT);
} else {
stopScan();
connTimeOutTimes = 0;
if (connectFunction != null) {
LogUtil.e(TAG, "连接超时：" + mBluetoothLeService.getConnectState());
connectFunction.onCallBack("{\"code\":-1,\"msg\":\"连接超时\",\"data\":\"false\"}");
connectFunction = null;
}
if (cardConnectFunction != null) {
cardConnectFunction.onCallBack("{\"code\":-1,\"msg\":\"连接超时\",\"data\":\"false\"}");
cardConnectFunction = null;
}
mBluetoothLeService.setConnectionState(0);
mBluetoothLeService.release();
bindStatus = 0;
}
}
};三、踩过坑的机型/ROM
- 1、小米/红米
MIUI11：必须打开位置服务才可搜索到BLE设备；
MIUI11及更早：
初始化BlueToothGatt时务必将connectGatt的autoConnect设为false，否则会被系统杀掉；
package android.bluetooth;
public final class BluetoothDevice implements Parcelable {
...
public BluetoothGatt connectGatt(Context context, boolean autoConnect,
BluetoothGattCallback callback) {
return (connectGatt(context, autoConnect, callback, TRANSPORT_AUTO));
}
}必须针对Android M及以上的MIUI配置调用BluetoothLeScanner.startScan()方法来搜索BLE设备，而非被废弃的BluetoothAdapter.startLeScan()，否则将无法搜索到设备，日志如下：
D/BluetoothAdapter: startLeScan(): null **注意，此处为null
D/BluetoothAdapter: isLeEnabled(): ON
D/BluetoothLeScanner: onScannerRegistered() - status=0 scannerId=6 mScannerId=0- 2、华为/荣耀
EMUI10（仅Mate 30/P30系列）：必须打开位置服务才可搜索到BLE设备 - 3、部分国产ROM（包括上述两类）：
部分机型需打开位置服务才可搜索到BLE设备；
部分机型需动态申请位置权限才可搜索到BLE设备；
部分机型需将connectGatt的autoConnect设为false（MIUI、ColorOS）；
部分机型需针对Android M及以上的系统版本配置调用BluetoothLeScanner.startScan()方法来搜索BLE设备；
四、附录：连接日志（MIUI）
E/系统版本：: >=6.0
D/BluetoothAdapter: isLeEnabled(): ON
D/BluetoothLeScanner: onScannerRegistered() - status=0 scannerId=8 mScannerId=0
E/发现设备：: xx:xx:xx:xx:xx:xx
E/WebViewActivity: 搜索到匹配的蓝牙设备(6.0+): xx:xx:xx:xx:xx:xx
D/BluetoothAdapter: isLeEnabled(): ON
I/WebViewActivity: xx:xx:xx:xx:xx:xx
E/BlueToothService: xx:xx:xx:xx:xx:xx
D/BluetoothGatt: onClientConnectionState() - status=0 clientIf=7 device=xx:xx:xx:xx:xx:xx
D/BluetoothGatt: discoverServices() - device: xx:xx:xx:xx:xx:xx
E/WebViewActivity: 连接成功：2
D/BluetoothGatt: onConnectionUpdated() - Device=xx:xx:xx:xx:xx:xx interval=6 latency=0 timeout=500 status=0
D/BluetoothGatt: onSearchComplete() = Device=xx:xx:xx:xx:xx:xx Status=0
D/BluetoothGatt: setCharacteristicNotification() - uuid: 0000fff4-xxxx-xxxx-xxxx-00xxxx9bxxxx enable: true
D/BluetoothGatt: onConnectionUpdated() - Device=xx:xx:xx:xx:xx:xx interval=36 latency=0 timeout=500 status=0
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