Start / stop built-in Wi-Fi / USB tethering from code?

Question

How can I start or stop the built-in tethering in Android 2.2 from my application?

Answer 1

There is a non-public Tethering API in the ConnectivityManager. As shown above you can use reflection to access it. I tried this on a number of Android 2.2 phones, and it works on all of them (my HTC turns on tethering but does NOT show this in the status bar..., so check from the other end). Below is some rough code which emits debugging stuff and turns on tethering on usb0.

ConnectivityManager cman = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

Method[] methods = cman.getClass().getDeclaredMethods();
for (Method method : methods) {
    if (method.getName().equals("getTetherableIfaces")) {
        try {
            String[] ifaces = (String[]) method.invoke(cman);
            for (String iface : ifaces) {
                Log.d("TETHER", "Tether available on " + iface);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    if (method.getName().equals("isTetheringSupported")) {
        try {
            boolean supported = (Boolean) method.invoke(cman);
            Log.d("TETHER", "Tether is supported: " + (supported ? "yes" : "no"));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    if (method.getName().equals("tether")) {
        Log.d("TETHER", "Starting tether usb0");
        try {
            int result = (Integer) method.invoke(cman, "usb0");
            Log.d("TETHER", "Tether usb0 result: " + result);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Please note: this code requires the following permissions to work:

android.permission.ACCESS_NETWORK_STATE
android.permission.CHANGE_NETWORK_STATE