Android 怎么监听蓝牙设备连接断开的广播

在 Android 中，可以通过注册广播接收器来监听蓝牙设备的连接和断开事件。具体步骤如下：

1. 在 AndroidManifest.xml 文件中添加以下权限：

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

2. 创建一个广播接收器类，继承 BroadcastReceiver 并实现 onReceive 方法：

public class BluetoothReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
            // 蓝牙设备连接成功
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            Log.i("BluetoothReceiver", "Device connected: " + device.getName());
        } else if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action)) {
            // 蓝牙设备连接断开
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            Log.i("BluetoothReceiver", "Device disconnected: " + device.getName());
        }
    }
}

3. 在需要监听蓝牙设备连接和断开事件的地方，注册广播接收器：

BluetoothReceiver receiver = new BluetoothReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction(BluetoothDevice.ACTION_ACL_CONNECTED);
filter.addAction(BluetoothDevice.ACTION_ACL_DISCONNECTED);
registerReceiver(receiver, filter);

注意：在不需要监听蓝牙设备连接和断开事件时，需要调用 unregisterReceiver 方法来取消注册广播接收器，以避免内存泄漏。