安卓上的蓝牙：启动发现不起作用，我启用了蓝牙

Question

我在使用startDiscovery()时遇到麻烦。这里是问题，我已经注册了以下intent到我的BroadcastReceiver，像这样:

IntentFilter filterFound = new IntentFilter(BluetoothDevice.ACTION_FOUND);
IntentFilter filterStart = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
IntentFilter filterStop = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
registerReceiver(myReceiver, filterFound);
registerReceiver(myReceiver, filterStart);
registerReceiver(myReceiver, filterStop);

这是我的广播接收器:

private BroadcastReceiver myReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
    Log.d(TAG, "onReceive (myReceiver)");
    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);
        // Add the name and address to an array adapter to show in a ListView
        Log.d(TAG,device.getName() + " " + device.getAddress());
        deviceListAdapter.add(device.getName() + "n" + device.getAddress());
    }
    if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
        Log.d(TAG, "Started discovery");
    }
    if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
        Log.d(TAG, "Finished discovery");
    }
}
};

当我在蓝牙适配器(蓝牙存在并启用)上调用startDiscovery时，没有任何事情发生，我无法在logcat中看到关于BroadcastReceiver的任何内容。

你曾经遇到过这种问题吗?任何帮助都是感激的:)

谢谢

Answer 1

确保你在AndroidManifest.xml上有适当的权限。特别是，要执行发现，您需要<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />。

Answer 2

正如Brad Hein所提到的，确保AndroidManifest具有蓝牙权限。

    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH" />

按照以下方法注册蓝牙扫描结果广播接收器。

IntentFilter bluetoothFilter = new IntentFilter();
bluetoothFilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
bluetoothFilter.addAction(BluetoothDevice.ACTION_FOUND);
bluetoothFilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
registerReceiver(myReceiver, bluetoothFilter);

按如下方式启动蓝牙发现。

BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
   // No bluetooth Hardware found.
}
if (!bluetoothAdapter.isEnabled()) {
    // Bluetooth is OFF
}
if (bluetoothAdapter.isDiscovering()) {
    // cancel the discovery if it has already started
   bluetoothAdapter.cancelDiscovery();
}
if (bluetoothAdapter.startDiscovery()) {
    // bluetooth has started discovery
}

Answer 3

尝试如下声明接收方:

private class SingBroadcastReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction(); 
        if (action.equals(BluetoothAdapter.ACTION_DISCOVERY_STARTED)) {
            log(getTimeStamp() + ":discovery started");
        }

下面是函数调用的顺序:

1- cancelDiscovery() + getAdapter()

2-按如下方式启动接收器:

        mReceiver = new SingBroadcastReceiver();
        IntentFilter ifilter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        ifilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        ifilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
        this.registerReceiver(mReceiver, ifilter);

3 - startDiscovery ()