问如何通过USB连接Android设备和数码相机？

EN

import java.util.HashMap;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbManager;
import android.os.Bundle;

public class USBMainclass  extends Activity
{

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Intent intent =new Intent();
        UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
        UsbManager manager = (UsbManager)this.getSystemService(Context.USB_SERVICE);
        HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.USBCommunication"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="12" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >

        <activity android:name=".USBMainclass">
  <intent-filter>
  <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" /> 
  </intent-filter>
  <meta-data android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" /> 
  </activity>

    </application>

</manifest>