android – 如何以编程方式判断蓝牙设备是否已连接？

我知道如何获得配对设备列表,但我怎么知道它们是否已连接？

它必须是可能的,因为我看到它们列在我手机的蓝牙设备列表中,并说明了它们的连接状态.

解决方法:

为您的AndroidManifest添加蓝牙权限,

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

然后使用intent过滤器来监听ACTION_ACL_CONNECTED,ACTION_ACL_DISCONNECT_REQUESTED和ACTION_ACL_DISCONNECTED广播：

public void onCreate() {
    ...
    IntentFilter filter = new IntentFilter();
    filter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
    filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECT_REQUESTED);
    filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED);
    this.registerReceiver(mReceiver, filter);
}

//The BroadcastReceiver that listens for bluetooth broadcasts
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

        if (BluetoothDevice.ACTION_FOUND.equals(action)) {
           ... //Device found
        }
        else if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
           ... //Device is now connected
        }
        else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
           ... //Done searching
        }
        else if (BluetoothDevice.ACTION_ACL_DISCONNECT_REQUESTED.equals(action)) {
           ... //Device is about to disconnect
        }
        else if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action)) {
           ... //Device has disconnected
        }           
    }
};

几点说明：

>在应用程序启动时无法检索已连接设备的列表.蓝牙API不允许您进行查询,而是允许您收听更改.
>对上述问题的一个不好的工作是检索所有已知/配对设备的列表…然后尝试连接到每个设备(以确定您是否已连接).
>或者,您可以让后台服务观看蓝牙API并将设备状态写入磁盘,以便您的应用程序在以后使用.

标签：android-bluetooth,android
来源： https://codeday.me/bug/20190911/1804306.html