问题描述
我正在研究 BLE,必须使用特定的 udid 扫描 BLE 设备。
目前,所有支持 BLE 的设备都作为扫描结果。
为了避免和仅扫描特定设备,我所做的如下:
fun startScanDevices(interval: Long = Constants.DEFAULT_SCAN_TIME_OUT,connectedDevices: HashMap<String,BLEDeviceModel>? = null,scanWithId: String? = null,context: Activity? = null) {
this.context = context
if (scanWithId != null)
this.scanWithId = scanWithId
if (isBluetoothEnabled) {
clearDeviceList(connectedDevices)
val BLP_SERVICE_UUID = UUID.fromString(UUID_OF_DEVICE)
val serviceUUIDs = arrayOf<UUID>(BLP_SERVICE_UUID)
var filters: MutableList<ScanFilter?>? = null
if (serviceUUIDs != null) {
filters = ArrayList()
for (serviceUUID in serviceUUIDs) {
val filter: ScanFilter = ScanFilter.Builder()
.setServiceUuid(ParcelUuid(serviceUUID))
.build()
filters!!.add(filter)
}
}
val scanSettings: ScanSettings = ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)
.setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
.setMatchMode(ScanSettings.MATCH_MODE_AGGRESSIVE)
.setNumOfMatches(ScanSettings.MATCH_NUM_ONE_ADVERTISEMENT)
.setReportDelay(1L)
.build()
mBluetoothAdapter?.bluetoothLeScanner?.startScan(filters,scanSettings,scanCallback)
mScanning = true
handler.postDelayed(stopScanningRunnable,interval)
}
}
现在,在上面的方法中,您可以验证我是否将 filters 和 scanSettings 作为 startScan 方法的参数传递。 >
但是通过这两个参数,我得到以下错误:
2021-05-06 11:16:24.295 14669-14669/? E/AndroidRuntime:致命 例外:主进程:com.dev,PID:14669 java.lang.indexoutofboundsexception:索引:0,大小:0 在 java.util.ArrayList.get(ArrayList.java:437) 在 com.ble.BLEManager$scanCallback$1.onBatchScanResults(BLEManager.kt:153) 在 android.bluetooth.le.BluetoothLeScanner$BleScanCallbackWrapper$2.run(BluetoothLeScanner.java:627) 在 android.os.Handler.handleCallback(Handler.java:938) 在 android.os.Handler.dispatchMessage(Handler.java:99) 在 android.os.Looper.loop(Looper.java:246) 在 android.app.ActivityThread.main(ActivityThread.java:8506) 在 java.lang.reflect.Method.invoke(Native Method) 在 com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
这对于 startScan() 中的单个参数工作正常,如下所示 - 没有出现此错误:
mBluetoothAdapter?.bluetoothLeScanner?.startScan(scanCallback)
override fun onBatchScanResults(results: List<ScanResult>) {
results[0].device
super.onBatchScanResults(results)
}
编辑
删除了这个不必要的名为:onBatchScanResults的方法 因为我使用的是 onScanResult。
现在,错误不会出现,但无法使用过滤器和 scanSettings 扫描任何设备。
可能是什么问题?请指导。谢谢。
解决方法
步骤 1) 像这样添加过滤器:
String[] filterNames = intent.getStringArrayExtra(FILTER_NAME_LIST);
String[] filterMacs = intent.getStringArrayExtra(FILTER_MAC_LIST);
String[] ignoreMacs = intent.getStringArrayExtra(IGNORE_MAC_LIST);
mFilter = new ScanServiceFilter.Builder() .filterNames(filterNames) .filterMacs(filterMacs) .ignoreMacs(ignoreMacs) .build();
第 2 步:调用 scanLeDevice()
scanLeDevice(true);
第 3 步: scanLeDevice 创建设置
ScanSettings settings = new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
.setCallbackType(CALLBACK_TYPE_ALL_MATCHES)
.setMatchMode(MATCH_MODE_AGGRESSIVE)
.setNumOfMatches(MATCH_NUM_FEW_ADVERTISEMENT)
.setReportDelay(0)
.build();
// We only want to scan for devices advertising our custom service
ScanFilter scanFilter = new ScanFilter.Builder()
.setServiceUuid(new ParcelUuid(UUIDConstants.RX_SERVICE_UUID)).build();
if (mBluetoothLeScanner != null && mBluetoothAdapter.getState() == BluetoothAdapter.STATE_ON) {
mBluetoothLeScanner.startScan(Collections.singletonList(scanFilter),settings,mScanCallback);
broadcastAction(new ScanBleActionEvent(ScanBleActionEvent.Actions.SCAN_STARTED));
} else {
bluetoothDeviceStopped();
}
第 4 步:关于 ScanCallback 检查
if (mFilter.passesFilter(scanDevice)) {
filteredResults.add(scanDevice);
broadcastAction(new ScanBleActionEvent(ScanBleActionEvent.Actions.SCANNED_DEVICE,scanDevice));
}