java - SEservice中Executor的使用方法(Open Mobile API for Android 9.0)

Question

我正在研究 NFC，目前正在尝试为 Android 9.0 内置的 Open Mobile API 编写代码，但不了解在 SEService 中传递 Executor 参数的方式。

public class MainActivity extends Activity implements SEService.OnConnectedListener {

    final String LOG_TAG = "NfcTest";

    private SEService seService;

    private Button button;


    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        LinearLayout layout = new LinearLayout(this);
        layout.setLayoutParams(new LayoutParams(
                LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT));

        button = new Button(this);
        button.setLayoutParams(new LayoutParams(
                LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT));

        button.setText("Click Me");
        button.setEnabled(false);
        button.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                try {

                    Reader[] readers = seService.getReaders();
                    if (readers.length < 1)
                        return;


                    Session session = readers[0].openSession();



                    Channel channel = session.openLogicalChannel(new byte[]{
                            (byte) 0xF0, 0x51, (byte) 0xBC, 0x53, 0x54, 0x69, 0x64,
                            (byte) 0x4D, 0x6F, 0x62, 0x69, (byte) 0x6C,
                            (byte) 0x65, 0x2D, (byte) 0x49, 0x44});


                    byte[] respApdu = channel.transmit(new byte[]{
                            (byte) 0x90, 0x10, 0x00, 0x00, 0x00});

                    channel.close();

                    // Parse response APDU and show text but remove SW1 SW2 first
                    byte[] helloStr = new byte[respApdu.length - 2];
                    System.arraycopy(respApdu, 0, helloStr, 0, respApdu.length - 2);
                    Toast.makeText(MainActivity.this, new String(helloStr), Toast.LENGTH_LONG).show();
                } catch (Exception e) {
                    Log.i(LOG_TAG, "Message: " + e.getClass().getCanonicalName());
                    if(e.getClass().isInstance(new NoSuchElementException()))
                        Toast.makeText(MainActivity.this, "NFC sim", Toast.LENGTH_LONG).show();
                    else if (e.getClass().isInstance(new IOException())){
                        Toast.makeText(MainActivity.this, "No sim found", Toast.LENGTH_LONG).show();
                    }
                    else{
                        Toast.makeText(MainActivity.this, "Normal sim", Toast.LENGTH_LONG).show();
                    }
                }
            }
        });

        layout.addView(button);
        setContentView(layout);


        try {

            seService = new SEService(this, this,this);
        } catch (SecurityException e) {
            Log.e(LOG_TAG, "Binding not allowed, uses-permission org.simalliance.openmobileapi.SMARTCARD?");
        } catch (Exception e) {
            Log.e(LOG_TAG, "Exception: " + e.getMessage());
        }
    }

    @Override
    protected void onDestroy() {
        if (seService != null && seService.isConnected()) {
            seService.shutdown();
        }
        super.onDestroy();
    }

    public void serviceConnected(SEService service) {
        Log.i(LOG_TAG, "seviceConnected()");
        button.setEnabled(true);
    }

    @Override
    public void onConnected() {

    }
}

问题发生在:

seService = new SEService(this, this,this);

接受了第一个和最后一个参数，中间一个执行器出现错误!

java.util.concurrent.Executor this

如何通过这个？

Answer 1

您收到此错误是因为构造函数 SEService 的第二个参数必须是 java.util.concurrent.Executor。您的 MainActivity(this 对象)没有实现执行器。

SEService 使用这个执行器来调用回调方法。所以你必须自己创建这样一个执行器，以便将它传递给 SEService。例如，您可以简单地创建一个带有单个工作线程的 ExecutorService 来处理回调:

ExecutorService pool = Executors.newSingleThreadExecutor();
seService = new SEService(this, pool, this);

但请注意，这些回调随后会在工作线程(而不是应用程序的主线程)上执行。因此，如果您想从回调中执行任何 UI 操作，则需要在 UI 线程上显式运行它们，例如

runOnUiThread(new Runnable() {
    void run() {
        button.setEnabled(true); // ... or some other UI modifications
    }
});