USB: Add functions for querying if a USB function is supported and enabled. (08bff3b9) · Commits · e / os / android_frameworks_base

core/java/android/hardware/Usb.java

+30 −0

Original line number	Diff line number	Diff line
		@@ -17,6 +17,10 @@

		package android.hardware;

		import java.io.File;
		import java.io.FileInputStream;
		import java.io.IOException;

		/**
		* Class for accessing USB state information.
		* @hide
		@@ -114,4 +118,30 @@ public class Usb {
		* Used in extras for the {@link #ACTION_USB_CONNECTED} broadcast
		*/
		public static final String USB_FUNCTION_DISABLED = "disabled";

		private static File getFunctionEnableFile(String function) {
		return new File("/sys/class/usb_composite/" + function + "/enable");
		}

		/**
		* Returns true if the specified USB function is supported by the kernel.
		* Note that a USB function maybe supported but disabled.
		*/
		public static boolean isFunctionSupported(String function) {
		return getFunctionEnableFile(function).exists();
		}

		/**
		* Returns true if the specified USB function is currently enabled.
		*/
		public static boolean isFunctionEnabled(String function) {
		try {
		FileInputStream stream = new FileInputStream(getFunctionEnableFile(function));
		boolean enabled = (stream.read() == '1');
		stream.close();
		return enabled;
		} catch (IOException e) {
		return false;
		}
		}
		}