在写《Android蓝牙开发系列文章-蓝牙音箱连接》时，计划细化出两篇文章，分别是：
关于蓝牙设备类型分类的，这个已经完成了，阅读请点击《Android蓝牙开发系列文章-蓝牙设备类型知多少？》。
今天我们要完成的是另外一篇：如何扫描蓝牙设备，怎么快速的、准确的扫描设备。
你也许会问，什么叫准确的扫描设备？难道我们在扫描的时候可以指定要扫描设备吗？
答案是肯定的，让我们慢慢讲来~
目录
1.姿势一：扫描经典蓝牙
在《Android蓝牙开发系列文章-蓝牙设备类型知多少？》中，我们没有提“经典蓝牙”和“低功耗蓝牙”的事儿，这里怎么又冒出了这两个概念?
其实，我们在上一节说的蓝牙设备类型，是从功能角度出发进行定义的一种概念。就是说这个蓝牙设备是个音箱，还是一个鼠标。
而今天说的这两个类型是比较专业化的概念，一般人，我是不告诉他的，谁让你关注了我呢，来，让我告诉你。
经典蓝牙设备：又称为传统蓝牙设备，英文为Classic Bluetooth，主要用于传输数据量比较大的功能传输，例如，蓝牙音箱。
低功耗蓝牙设备：英文为Bluetooth Low Energy，最大的特点是功耗的降低，主要用于实时性要求较高、但数据量不大的产品中，例如，蓝牙灯、蓝牙手环等等。
讲完了这两个概念，我们再来讲两个: 单模设备、双模设备。
单模设备：是指进具有经典蓝牙设备功能或者低功耗蓝牙功能的设备。例如，仅仅具有心率测量功能的手环。
双模设备：是指同时具有经典蓝牙设备功能和低功耗蓝牙功能的设备。例如，既具有心率测量功能，又具有通话功能的手环。再例如，我们现在智能电视的蓝牙遥控器（语音功能使用的是经典蓝牙，按键功能使用的是低功耗蓝牙）。再例如，小米的小爱音箱，它就是典型的双模设备，具有两个mac地址。
在这里要说一下，不是所有的双模设备都是两个mac地址，有的也仅是一个mac地址。我抽空会再写一下蓝牙mac 地址的分类（如果一直这样细化下去，不知道我的蓝牙专题是否要写100+篇？），不知道你是否期待？
讲完了概念，我们接着讲“姿势一”，如果你读过我之前写的蓝牙音箱连接的文章，你应该知道了经典蓝牙设备如何扫描了。
调用BluetoothAdapter::startDiscovery()接口，然后接受广播，从广播中解析出你想要的设备。这种方法扫描出的蓝牙设备不仅仅是只能扫描到经典蓝牙，也会扫描到低功耗蓝牙。如果你要扫描经典蓝牙的话，只能忍受这一个弊端了，因为没有别的招了。
如想了解经典蓝牙设备的扫描，请移步《Android蓝牙开发系列文章-蓝牙音箱连接》。我在这里就不再讲解一遍了。
2.姿势二：用过时的接口扫描低功耗蓝牙
下面开始讲一下经典蓝牙设备的扫描。
第一步，要先申请必要的权限，
<!--蓝牙权限-->
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<!--BLE扫描权限-->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<!--蓝牙ble feature检查，只有在由此feature的设备上才能安装本应用-->
<uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>我在写demo的过程中发现，静态申请了BLE扫描的权限没有生效，没有扫描到任何设备，经过上网百度获悉，从Android6.0开始需要动态申请位置权限，所以有了如下一段代码：
private void requestPermission() {
//动态申请是否有必要看sdk版本哈
if (Build.VERSION.SDK_INT < 23){return;}
//判断是否有权限
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
//请求权限
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, 1);
}
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
//请求权限
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
}
}先获取BluetoothAdapter对象，然后调用BluetoothAdapter::startLeScan(LeScanCallback callback)发起设备扫描。
扫码到的设备都会在onLeScan()中拿到。
//蓝牙编程千古不变：第一行代码
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Log.d(TAG, "mBluetoothAdapter = " + mBluetoothAdapter);
//设备回调，扫描到的设备都在onLeScan()中拿到
private static LeScanCallback mLeScanCallback = new LeScanCallback() {
@Override
public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {
if(device == null || device.getName() == null || device.getAddress() == null) {
return;
}
Log.d(TAG, "onLeScan(), device = " + device.getName() + "mac = " + device.getAddress() + "rssi = " + rssi);
for (int i = 0; i < scanRecord.length; i++) {
Log.d(TAG, "onLeScan(), device = " + device.getName() + "content = " + scanRecord[i]);
}
}
};
//调用BluetoothAdapter.startLeScan(LeScanCallback callback)发起设备扫描
private void startBleScan1() {
boolean ret = mBluetoothAdapter.startLeScan(mLeScanCallback);
Log.d(TAG, "startBtScan(),ret = " + ret);
}运行一下我们的demo，看一下扫描结果，家里的唯一一个低功耗设备，蓝牙体脂秤，被扫描出来了。
03-16 21:07:32.130 9909-9909/com.atlas.devicefinder D/MainActivity: mBluetoothAdapter = android.bluetooth.BluetoothAdapter@ddeeda9
03-16 21:07:32.131 9909-9909/com.atlas.devicefinder D/MainActivity: mBluetoothLeScanner = android.bluetooth.le.BluetoothLeScanner@e0adf2e
03-16 21:07:34.947 9909-9909/com.atlas.devicefinder D/MainActivity: onClick,View = androidx.appcompat.widget.AppCompatButton{e036fde VFED..C.. ...P.... 0,0-426,144 #7f070042 app:id/bt_start_blescan1}
03-16 21:07:34.970 9909-9909/com.atlas.devicefinder D/MainActivity: startBtScan(),ret = true
03-16 21:07:40.498 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9mac = 08:7C:BE:48:65:ADrssi = -78
03-16 21:07:40.499 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 10
03-16 21:07:40.501 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 9
03-16 21:07:40.503 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 49
03-16 21:07:40.505 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 76
03-16 21:07:40.508 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 83
03-16 21:07:40.509 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 95
03-16 21:07:40.512 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 87
03-16 21:07:40.513 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 95
03-16 21:07:40.515 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 57
03-16 21:07:40.517 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 0
03-16 21:07:40.518 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 0
03-16 21:07:40.519 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 2
03-16 21:07:40.521 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 1
03-16 21:07:40.524 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 6
03-16 21:07:40.526 9909-9909/com.atlas.devicefinder D/MainActivity: onLeScan(), device = 1LS_W_9content = 5因为家里只有一个低功耗蓝牙设备，所以没有扫描出来其他设备（这可不是因为这个接口具有扫描指定设备的功能哈，因为它并没有，不然怎么被废弃了呢）。
3.姿势三：用时髦的接口扫描低功耗蓝牙
这里将一个时髦的蓝牙扫描接口，BluetoothLeScanner::startScan()。这个接口的定义如下所示，第一个参数就是对扫描到的设备的过滤条件，第二个参数表示的是对本次扫描的设置，第三个参数用于接收扫描结果（如果有过滤条件，则是经过滤后的设备）。
/**
* Start Bluetooth LE scan. The scan results will be delivered through {@code callback}.
* For unfiltered scans, scanning is stopped on screen off to save power. Scanning is
* resumed when screen is turned on again. To avoid this, do filetered scanning by
* using proper {@link ScanFilter}.
* <p>
* An app must hold
* {@link android.Manifest.permission#ACCESS_COARSE_LOCATION ACCESS_COARSE_LOCATION} or
* {@link android.Manifest.permission#ACCESS_FINE_LOCATION ACCESS_FINE_LOCATION} permission
* in order to get results.
*
* @param filters {@link ScanFilter}s for finding exact BLE devices.
* @param settings Settings for the scan.
* @param callback Callback used to deliver scan results.
* @throws IllegalArgumentException If {@code settings} or {@code callback} is null.
*/
@RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
public void startScan(List<ScanFilter> filters, ScanSettings settings,
final ScanCallback callback) {
startScan(filters, settings, null, callback, /*callbackIntent=*/ null, null);
}我们先不设置过滤条件，看一下该方法如何使用:
先获取BluetoothLeScanner对象，然后调用其startScan(ScanCallback callback)方法，看到没，就只有一个回调参数。
//先获取BluetoothLeScanner对象
private BluetoothLeScanner mBluetoothLeScanner = null;
mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();
private void startBleScan2() {
mBluetoothLeScanner.startScan(mScanCallback);
}
//回调接口
private static ScanCallback mScanCallback = new ScanCallback() {
//每扫描到一个BLE设备，就接收到一次回调
@Override
public void onScanResult(int callbackType, ScanResult result) {
super.onScanResult(callbackType, result);
Log.d(TAG, "onScanResult, result = " + result);
}
//批量回调接口
@Override
public void onBatchScanResults(List<ScanResult> results) {
super.onBatchScanResults(results);
Log.d(TAG, "onBatchScanResults");
}
//扫描失败的回调，可以根据失败的原因执行不同策略，例如，重新扫描或者
//先停止当前扫描，再重新发起扫描
@Override
public void onScanFailed(int errorCode) {
super.onScanFailed(errorCode);
Log.d(TAG, "onScanFailed, errorCode = " + errorCode);
}
};我们这样搞，会得到一个什么样的扫描结果呢？可以看到除了我家的体脂秤，也扫描到了另外一个BLE设备（反正不是俺家的，不知道谁的）。我还特意把我家的蓝牙音箱打开了，结果可想而知：扫不到~
03-15 20:41:37.946 10425-10425/com.atlas.devicefinder D/MainActivity: mBluetoothAdapter = android.bluetooth.BluetoothAdapter@bc4da35
03-15 20:41:37.947 10425-10425/com.atlas.devicefinder D/MainActivity: mBluetoothLeScanner = android.bluetooth.le.BluetoothLeScanner@74b3eca
03-15 20:41:41.476 10425-10425/com.atlas.devicefinder D/MainActivity: onClick,View = androidx.appcompat.widget.AppCompatButton{e98ee7a VFED..C.. ...P.... 0,288-426,432 #7f070043 app:id/bt_start_blescan2}
03-15 20:41:47.466 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-97, mTimestampNanos=86214200338022}
03-15 20:41:52.332 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-94, mTimestampNanos=86219088416145}
03-15 20:41:56.438 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-94, mTimestampNanos=86223197857185}
03-15 20:41:58.892 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-93, mTimestampNanos=86225651024476}
03-15 20:42:04.863 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-95, mTimestampNanos=86231621502599}
03-15 20:42:05.935 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-94, mTimestampNanos=86232694169265}
03-15 20:42:12.296 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=08:7C:BE:48:65:AD, mScanRecord=ScanRecord [mAdvertiseFlags=6, mServiceUuids=[0000fee7-0000-1000-8000-00805f9b34fb, 0000d618-0000-1000-8000-00805f9b34fb], mManufacturerSpecificData={0=[8, 124, -66, 72, 101, -83]}, mServiceData={}, mTxPowerLevel=-2147483648, mDeviceName=1LS_W_9����], mRssi=-71, mTimestampNanos=86239051067804}
03-15 20:42:12.436 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-94, mTimestampNanos=86239196387388}
03-15 20:42:12.712 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-98, mTimestampNanos=86239469748846}
03-15 20:42:17.346 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-87, mTimestampNanos=86244101039261}
03-15 20:42:17.616 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-87, mTimestampNanos=86244372349886}
03-15 20:42:22.388 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5A:C1:FA:54:54:0F, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, 17, 115, -33]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-42, mTimestampNanos=86249143803842}
03-15 20:42:22.657 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5A:C1:FA:54:54:0F, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, 17, 115, -33]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-42, mTimestampNanos=86249413593842}
03-15 20:42:27.374 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5A:C1:FA:54:54:0F, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, 17, 115, -33]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-50, mTimestampNanos=86254130413424}
03-15 20:42:27.421 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-96, mTimestampNanos=86254178738632}
03-15 20:42:27.642 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5A:C1:FA:54:54:0F, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, 17, 115, -33]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-38, mTimestampNanos=86254399760298}
03-15 20:42:27.693 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-96, mTimestampNanos=86254451050298}
03-15 20:42:32.251 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5A:C1:FA:54:54:0F, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, 17, 115, -33]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-39, mTimestampNanos=86259010351130}
03-15 20:42:32.309 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5B:CE:4F:45:38:61, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, -47, -34, -112]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-93, mTimestampNanos=86259068604255}
03-15 20:42:32.527 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5A:C1:FA:54:54:0F, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, 17, 115, -33]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-40, mTimestampNanos=86259282907588}
03-15 20:42:37.525 10425-10425/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=5A:C1:FA:54:54:0F, mScanRecord=ScanRecord [mAdvertiseFlags=26, mServiceUuids=null, mManufacturerSpecificData={76=[16, 5, 81, 28, 17, 115, -33]}, mServiceData={}, mTxPowerLevel=12, mDeviceName=null], mRssi=-37, mTimestampNanos=86264281754670}
既然这种扫描方式可以对扫描和过滤进行设置，那我们来试一下子吧~
在这里，我想仅仅扫描家里的体脂秤，所以，调用了setDeviceAddress(string)方法，把体脂秤的mac地址传递进去。
其实，这个时候就OK了，因为蓝牙mac地址是设备的唯一标识嘛，这样设备就一定会只扫描到我的目标设备了。
可是，我想把事情搞大一点，给过滤再加点限制，看是否还能扫描成功。
我又setServiceUuid()方法将体脂秤支持的service uuid传递进来。
//过滤条件
List<ScanFilter> bleScanFilters = new ArrayList<>();
ScanFilter filter = new ScanFilter.Builder().setDeviceAddress("08:7C:BE:48:65:AD").setServiceUuid(ParcelUuid.fromString("0000fee7-0000-1000-8000-00805f9b34fb")).build();
bleScanFilters.add(filter);再来对扫描设置进行一些定制：
设置扫描模式为低延迟模式，这种模式下可以更快的进行设备扫描，除此之外，还有均衡模式（SCAN_MODE_BALANCED）、低功耗模式（SCAN_MODE_LOW_POWER）。从字面意思，你应该也能猜出来，低延迟模式扫描设备最快，低功耗模式扫描设备最慢，均衡模式居中。
设置回调模式为全匹配（CALLBACK_TYPE_ALL_MATCHES），就是说，如果我们设置了过滤条件，则只上报过滤条件都完全匹配的设备，如果没有设置任何过滤条件，则上报扫描到的所有设备。
设置粘性匹配，就是在扫描到的设备满足一定信号强度时，才去跟过滤条件进行匹配，信号强度太弱，蓝牙固件直接丢弃，也不会去做匹配操作。
最后，我们将两个参数传递到startScan()方法中来。
//扫描设置
ScanSettings scanSetting = new ScanSettings.Builder().setScanMode(SCAN_MODE_LOW_LATENCY).setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES).setMatchMode(ScanSettings.MATCH_MODE_STICKY).build();
mBluetoothLeScanner.startScan(bleScanFilters, scanSetting, mScanCallback);看一下此时的扫描结果，我们的目标设备是可以正常扫描到，并且上报设备的粒度明显降低了。
03-15 21:12:14.335 16060-16060/com.atlas.devicefinder D/MainActivity: onClick,View = androidx.appcompat.widget.AppCompatButton{e98ee7a VFED..C.. ...P.... 0,288-426,432 #7f070043 app:id/bt_start_blescan2}
03-15 21:12:15.177 16060-16060/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=08:7C:BE:48:65:AD, mScanRecord=ScanRecord [mAdvertiseFlags=6, mServiceUuids=[0000fee7-0000-1000-8000-00805f9b34fb, 0000d618-0000-1000-8000-00805f9b34fb], mManufacturerSpecificData={0=[8, 124, -66, 72, 101, -83]}, mServiceData={}, mTxPowerLevel=-2147483648, mDeviceName=1LS_W_9����], mRssi=-77, mTimestampNanos=88041917514200}
03-15 21:12:19.962 16060-16060/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=08:7C:BE:48:65:AD, mScanRecord=ScanRecord [mAdvertiseFlags=6, mServiceUuids=[0000fee7-0000-1000-8000-00805f9b34fb, 0000d618-0000-1000-8000-00805f9b34fb], mManufacturerSpecificData={0=[8, 124, -66, 72, 101, -83]}, mServiceData={}, mTxPowerLevel=-2147483648, mDeviceName=1LS_W_9����], mRssi=-85, mTimestampNanos=88046719595240}
03-15 21:12:22.366 16060-16060/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=08:7C:BE:48:65:AD, mScanRecord=ScanRecord [mAdvertiseFlags=6, mServiceUuids=[0000fee7-0000-1000-8000-00805f9b34fb, 0000d618-0000-1000-8000-00805f9b34fb], mManufacturerSpecificData={0=[8, 124, -66, 72, 101, -83]}, mServiceData={}, mTxPowerLevel=-2147483648, mDeviceName=1LS_W_9����], mRssi=-70, mTimestampNanos=88049124682114}
03-15 21:12:24.775 16060-16060/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=08:7C:BE:48:65:AD, mScanRecord=ScanRecord [mAdvertiseFlags=6, mServiceUuids=[0000fee7-0000-1000-8000-00805f9b34fb, 0000d618-0000-1000-8000-00805f9b34fb], mManufacturerSpecificData={0=[8, 124, -66, 72, 101, -83]}, mServiceData={}, mTxPowerLevel=-2147483648, mDeviceName=1LS_W_9����], mRssi=-70, mTimestampNanos=88051533382946}
03-15 21:12:27.180 16060-16060/com.atlas.devicefinder D/MainActivity: onScanResult, result = ScanResult{mDevice=08:7C:BE:48:65:AD, mScanRecord=ScanRecord [mAdvertiseFlags=6, mServiceUuids=[0000fee7-0000-1000-8000-00805f9b34fb, 0000d618-0000-1000-8000-00805f9b34fb], mManufacturerSpecificData={0=[8, 124, -66, 72, 101, -83]}, mServiceData={}, mTxPowerLevel=-2147483648, mDeviceName=1LS_W_9����], mRssi=-70, mTimestampNanos=88053936127529}
4.总结
利用上面提到了方式3 来进行设备扫描有什么好处呢？
在蓝牙固件中即进行设备匹配，可以大大减少蓝牙协议栈以及应用层的操作，降低内存占用、CPU占用。
可以根据需要进行扫描参数的设置，实现动态调整，进而实现快速扫描目标设备。
天不早了，该休息了~
本博客始终坚持理论与实践相结合，想尽最大努力将知识点讲解清楚，但不知道实际效果如何，
如果有任何建议，可以随时跟我沟通，谢谢。
如果想持续关注本博客内容，请扫描关注个人微信公众号，或者微信搜索：万物互联技术。
