在Android应用程序中注册了一个蓝牙广播接收器

在Android应用程序中注册蓝牙广播接收器，可以监听蓝牙设备的状态变化、连接状态变化等事件。下面是一个简单的示例代码：

public class BluetoothReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
            int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);
            switch (state) {
                case BluetoothAdapter.STATE_OFF:
                    // 蓝牙关闭
                    break;
                case BluetoothAdapter.STATE_TURNING_OFF:
                    // 蓝牙正在关闭
                    break;
                case BluetoothAdapter.STATE_ON:
                    // 蓝牙开启
                    break;
                case BluetoothAdapter.STATE_TURNING_ON:
                    // 蓝牙正在开启
                    break;
            }
        } else if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
            // 蓝牙设备已连接
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
        } else if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action)) {
            // 蓝牙设备已断开连接
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
        }
    }
}

在你的Activity或Service中，你需要注册此广播接收器，代码如下：

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

在不需要接收蓝牙广播事件时，也要及时取消注册广播接收器，代码如下：

unregisterReceiver(receiver);