我想找到蓝牙扫描仪是否每7秒钟连接到我的Android手机。为此，我创建了一个receiver，在那里我找到了bondeddevices然后找到了它的主要类。但它没有找到任何设备。可能是什么问题？
这里是活动类：
public class Activity_Home extends ActionBarActivity implements
OnClickListener {
CountDownTimer wifiTimer, timer;
BluetoothAdapter mBluetoothAdapter;
BluetoothDevice bluetoothDevice;
CheckBluetoothScanner mReceiver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mReceiver = new CheckBluetoothScanner();
isScannerConnected();
}
private void isScannerConnected() {
timer = new CountDownTimer(Long.MAX_VALUE, 7000) { // -------call
// amethod
// after
// certain
// time
// interval-------
// This is called every interval. (Every 7 seconds in this example)
public void onTick(long millisUntilFinished) {
Log.d("test", "Timer tick");
System.out.println("=======bluetooth--start");
try {
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter.isEnabled()) {
IntentFilter filter = new IntentFilter(
BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter);
mBluetoothAdapter.startDiscovery();
System.out.println("============utility: "
+ Utility.SCANNER_ON);
if (Utility.SCANNER_ON.equalsIgnoreCase("true")) {
tv_scanner
.setBackgroundResource(R.drawable.scanner);
} else {
tv_scanner.setBackgroundResource(0);
}
} else {
tv_scanner.setBackgroundResource(0);
}
} catch (NullPointerException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public void onFinish() {
Log.d("test", "Timer last tick");
timer.cancel();
}
}.start();
}
这是接收者类：
public class CheckBluetoothScanner extends BroadcastReceiver {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,
BluetoothAdapter.ERROR);
}
else if (BluetoothDevice.ACTION_FOUND.equals(action)) {
BluetoothDevice device = (BluetoothDevice) intent
.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Set pairedDevices = BluetoothAdapter.getDefaultAdapter()
.getBondedDevices();
BluetoothDevice device1 = null;
for (Object item : pairedDevices) {
device1 = (BluetoothDevice) item;
}
BluetoothClass bluetoothClass = device1.getBluetoothClass();
System.out.println("======bluetoothClass"+bluetoothClass);
if (bluetoothClass != null) {
int deviceClass = bluetoothClass.getDeviceClass();
System.out.println("=======deviceclass:"+deviceClass);
if (deviceClass == Device.Major.IMAGING
|| deviceClass == Device.Major.PERIPHERAL) {
Utility.SCANNER_ON = "true";
} else {
Utility.SCANNER_ON = "false";
}
}
}
}
};