嗨，这可能听起来是一个愚蠢的问题。但我无法找到任何答案，因此在这里发帖。
我正在构建一个室内应用程序，它可以连续扫描位于商场或图书馆等地方不同位置的蓝牙适配器。当我手里拿着 Android 手机在商场里移动时，我应该能够获得距离我最近的适配器连接到（愚蠢的想法，但我想用它做点别的事情）。为此我应该能够连续扫描蓝牙设备。
请有人告诉我如何让 android 定期扫描可用的蓝牙设备。
我想这很简单，但之前我并没有想到。答案在这里
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这是获取所有活动蓝牙设备[配对或未配对]
列表的代码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 演示中得到了这个想法，我希望这对所有开发人员都有用。
如文档中所述，设备发现是一个复杂的过程，会直接降低您与其他设备之间的任何联系的性能。
注意：执行设备发现对于系统来说是一个繁重的过程 并且蓝牙适配器会消耗其大量的资源。一旦您 已找到要连接的设备，请确保始终停止 在尝试连接之前使用 cancelDiscovery() 进行发现。还， 如果您已经与设备保持连接，则执行 发现可以显着减少可用带宽 连接，因此您不应在连接时执行发现。
考虑到这一点（省略错误处理）：
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();
}
}
}
您的代码片段应该可以工作 - 只是它在功耗方面会很昂贵，并且肯定会在几个小时内杀死您的设备/手机。 startDiscovery() 执行两步过程，通过查询来查找设备，然后进行名称发现，即寻呼并连接到设备，
不幸的是，Android 没有提供任何 API 来控制这一点，并且只进行查询，而且大多数蓝牙芯片组都定义和支持定期查询功能，Android 目前没有任何 API 来进行定期查询，这可能更适合您使用案例。