一插上USB外设以后 直接跳到相应的…

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

<activity android:name=".TestActivity"

android:label="@string/app_name">

<intent-filter>

<action android:name="android.intent.action.MAIN"
/>

<category
android:name="android.intent.category.LAUNCHER"
/>

<category
android:name="android.intent.category.DEFAULT"></category>

</intent-filter>

<intent-filter>

<action
android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"></action>

</intent-filter>

<meta-data
android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
android:resource="@xml/device_filter"></meta-data>

</activity>

</application>

加上：

<intent-filter>

<action
android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"></action>

</intent-filter>

就可以了