如何定期扫描Android上的蓝牙设备

嗨,这可能听起来像一个愚蠢的问题。但我无法find任何答案,因此张贴在这里。

我正在build立一个室内应用程序,它不断地扫描位于商场或图书馆等地的不同位置的蓝牙适配器。当我在商场中用手机移动手机时,我应该能够find最近的可以连接的encryption狗(愚蠢的想法,但我想用这个做别的事情)。为此,我应该能够不断扫描蓝牙设备。

请有人可以告诉我如何让Android定期扫描可用的蓝牙设备。

Solutions Collecting From Web of "如何定期扫描Android上的蓝牙设备"

我想这是如此简单,但没有打击我之前。 这是答案,

private BluetoothAdapter mBtAdapter; mBtAdapter.startDiscovery(); private final BroadcastReceiver mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); // When discovery finds a device if (BluetoothDevice.ACTION_FOUND.equals(action)) { //do something } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { Log.v(TAG,"Entered the Finished "); mBtAdapter.startDiscovery(); } 

因此,我们应该在ACTION_DISCOVERY_FINISHED上再次开始发现,这将每隔12秒连续扫描一次设备。

以下是获取所有有源蓝牙设备列表的代码[配对或不配对]

 import java.util.Set; import android.app.Activity; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.Window; import android.view.View.OnClickListener; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ListView; import android.widget.TextView; import android.widget.AdapterView.OnItemClickListener; /** * This Activity appears as a dialog. It lists any paired devices and * devices detected in the area after discovery. When a device is chosen * by the user, the MAC address of the device is sent back to the parent * Activity in the result Intent. */ public class DeviceListActivity extends Activity { // Debugging private static final String TAG = "DeviceListActivity"; private static final boolean D = true; // Return Intent extra public static String EXTRA_DEVICE_ADDRESS = "device_address"; // Member fields private BluetoothAdapter mBtAdapter; private ArrayAdapter<String> mPairedDevicesArrayAdapter; private ArrayAdapter<String> mNewDevicesArrayAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Setup the window requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS); setContentView(R.layout.activity_device_list); // Initialize the button to perform device discovery Button scanButton = (Button) findViewById(R.id.button_scan); scanButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { doDiscovery(); v.setVisibility(View.GONE); } }); // Initialize array adapters. One for already paired devices and // one for newly discovered devices mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name); mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name); // Find and set up the ListView for paired devices ListView pairedListView = (ListView) findViewById(R.id.paired_devices); pairedListView.setAdapter(mPairedDevicesArrayAdapter); pairedListView.setOnItemClickListener(mDeviceClickListener); // Find and set up the ListView for newly discovered devices ListView newDevicesListView = (ListView) findViewById(R.id.new_devices); newDevicesListView.setAdapter(mNewDevicesArrayAdapter); newDevicesListView.setOnItemClickListener(mDeviceClickListener); // Register for broadcasts when a device is discovered IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); this.registerReceiver(mReceiver, filter); // Register for broadcasts when discovery has finished filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED); this.registerReceiver(mReceiver, filter); // Get the local Bluetooth adapter mBtAdapter = BluetoothAdapter.getDefaultAdapter(); // Get a set of currently paired devices Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices(); // If there are paired devices, add each one to the ArrayAdapter if (pairedDevices.size() > 0) { findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE); for (BluetoothDevice device : pairedDevices) { mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress()); } } else { String noDevices = getResources().getText(R.string.none_paired).toString(); mPairedDevicesArrayAdapter.add(noDevices); } } @Override protected void onDestroy() { super.onDestroy(); // Make sure we're not doing discovery anymore if (mBtAdapter != null) { mBtAdapter.cancelDiscovery(); } // Unregister broadcast listeners this.unregisterReceiver(mReceiver); } /** * Start device discover with the BluetoothAdapter */ private void doDiscovery() { if (D) Log.d(TAG, "doDiscovery()"); // Indicate scanning in the title setProgressBarIndeterminateVisibility(true); setTitle(R.string.scanning); // Turn on sub-title for new devices findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE); // If we're already discovering, stop it if (mBtAdapter.isDiscovering()) { mBtAdapter.cancelDiscovery(); } // Request discover from BluetoothAdapter mBtAdapter.startDiscovery(); } // The on-click listener for all devices in the ListViews private OnItemClickListener mDeviceClickListener = new OnItemClickListener() { public void onItemClick(AdapterView<?> av, View v, int i, long l) { // Cancel discovery because it's costly and we're about to connect mBtAdapter.cancelDiscovery(); // Get the device MAC address, which is the last 17 chars in the View String info = ((TextView) v).getText().toString(); String address = info.substring(info.length() - 17); } }; // The BroadcastReceiver that listens for discovered devices and // changes the title when discovery is finished private final BroadcastReceiver mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); // When discovery finds a device if (BluetoothDevice.ACTION_FOUND.equals(action)) { // Get the BluetoothDevice object from the Intent BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); // If it's already paired, skip it, because it's been listed already if (device.getBondState() != BluetoothDevice.BOND_BONDED) { mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress()); } // When discovery is finished, change the Activity title } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { setProgressBarIndeterminateVisibility(false); setTitle(R.string.select_device); if (mNewDevicesArrayAdapter.getCount() == 0) { String noDevices = getResources().getText(R.string.none_found).toString(); mNewDevicesArrayAdapter.add(noDevices); } } } }; } 

我从API演示中获得了这个想法,我希望这对所有开发人员都有用。

如文档中所述,设备发现是一个崇高的过程,会直接降低与其他设备之间的任何绑定的性能。

警告:执行设备发现是蓝牙适配器的一个沉重的过程,并将消耗大量的资源。 一旦find要连接的设备,请确保在尝试连接之前始终使用cancelDiscovery()停止发现。 另外,如果您已经与设备保持连接,则执行发现操作可能会显着减less可用于连接的带宽,因此连接时不应执行发现。

考虑到这一点(省略error handling):

 private final BroadcastReceiver deviceBroadcastReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (BluetoothDevice.ACTION_FOUND.equals(action)) { deviceFound = true; adapter.cancelDiscovery(); //process new device. deviceFound = false; adapter.startDiscovery(); } } private final BroadcastReceiver adapterBroadcastReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (BluetoothAdaptor.ACTION_DISCOVERY_FINISHED.equals(action)) { if (deviceFound == false) { adapter.startDiscovery(); } } } 

你的代码片段应该工作 – 只是这将是昂贵的功耗方面,肯定会在几个小时内杀死你的设备/手机。 startDiscovery()执行两个步骤,通过查询find设备,然后进行名称发现,即寻呼和连接到设备,

不幸的是,Android并没有提供任何API来控制这个,只做查询,也有大多数蓝牙芯片组定义和支持的定期查询function,Android目前没有任何API来做周期性的查询,可以更理想的使用案件。