如何使用NotificationListenerService将小图标从通知转换为byte[]？

public class MyNotificationListenerService extends NotificationListenerService {
    @Override
    public void onNotificationPosted(StatusBarNotification sbn) {
        // 获取通知的图标
        Icon smallIcon = sbn.getNotification().getSmallIcon();
        
        // 将图标转换为 byte[]
        byte[] iconBytes = getIconBytes(smallIcon);
        
        // 其他处理逻辑...
    }
    
    private byte[] getIconBytes(Icon icon) {
        // 将 Icon 转换为 Bitmap
        Bitmap bitmap = icon.loadDrawable(this).toBitmap();
        
        // 将 Bitmap 转换为 byte[]
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
        byte[] iconBytes = stream.toByteArray();
        
        return iconBytes;
    }
}

<manifest>
    <application>
        <service
            android:name=".MyNotificationListenerService"
            android:label="Notification Listener"
            android:permission="android.permission.BIND_NOTIFICATION_LISTENER_SERVICE">
            <intent-filter>
                <action android:name="android.service.notification.NotificationListenerService" />
            </intent-filter>
        </service>
    </application>
</manifest>

public class MainActivity extends AppCompatActivity {
    private static final int REQUEST_CODE = 1;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        // 请求获取通知监听权限
        requestNotificationListenerPermission();
    }
    
    private void requestNotificationListenerPermission() {
        if (!isNotificationListenerEnabled()) {
            Intent intent = new Intent(Settings.ACTION_NOTIFICATION_LISTENER_SETTINGS);
            startActivityForResult(intent, REQUEST_CODE);
        }
    }
    
    private boolean isNotificationListenerEnabled() {
        String packageName = getPackageName();
        String flat = Settings.Secure.getString(getContentResolver(), "enabled_notification_listeners");
        if (flat != null) {
            String[] names = flat.split(":");
            for (String name : names) {
                ComponentName componentName = ComponentName.unflattenFromString(name);
                if (componentName != null && TextUtils.equals(packageName, componentName.getPackageName())) {
                    return true;
                }
            }
        }
        return false;
    }
    
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        
        if (requestCode == REQUEST_CODE) {
            if (isNotificationListenerEnabled()) {
                // 已获取通知监听权限，可以开始监听通知
            } else {
                // 用户未授予通知监听权限，需要处理相应逻辑
            }
        }
    }
}