android.hardware.USB种介绍

android.hardware.USB类介绍
在最新的Android版本中，android.hardware.USB是一个新增类，提供了USB相关事件的插拔，以及状态模式的广播。这里，可以看到USB连接、断开、是否为U盘、ADB模式等等。定义如下

public class Usb {
    public static final String ACTION_USB_CONNECTED =
            "android.hardware.action.USB_CONNECTED";

     public static final String ACTION_USB_DISCONNECTED =
            "android.hardware.action.USB_DISCONNECTED";

    public static final String ACTION_USB_STATE =
            "android.hardware.action.USB_STATE";

    public static final String USB_CONNECTED = "connected";

    public static final String USB_FUNCTION_MASS_STORAGE = "mass_storage";

    public static final String USB_FUNCTION_ADB = "adb";

    public static final String USB_FUNCTION_RNDIS = "rndis";

    public static final String USB_FUNCTION_MTP = "mtp";

    public static final String USB_FUNCTION_ENABLED = "enabled";

    public static final String USB_FUNCTION_DISABLED = "disabled";