Android – USB Host Mode – device access permission granted but not remembered

androidhostusb

I have a USB Host Mode application that works perfectly. I plug in the device, Android pops up the Allow the app APPNAME to access the USB device? permission request window, I check the Use by default for this USB device tick box and tap OK, then up comes my app and it communicates with the USB device perfectly.

BUT…

Then I unplug the device and plug it back in. Android pops up the Allow the app APPNAME to access the USB device? dialog again. WTH? I've already told Android to do this by default, so why is it asking me again?

This happens both with Icecream Sandwich 4.0.3 and Jellybean 4.1.

Ideally I want Android to remember I've granted permission for this particular USB device even after I've rebooted the Android device.

So why isn't Android remembering that I've granted permission?

Best Answer

This is a dup of USB device access pop-up supression?. Basically the answer is to use an intent-filter on USB_DEVICE_ATTACHED and steer clear of the RequestPermission USB Host Mode API call.

Related Solutions

Java – Android 3.1 USB-Host – BroadcastReceiver does not receive USB_DEVICE_ATTACHED

Aha! I figured it out. I was having the exact same problem.

The gist of it is - if you have your application launch automatically when a device is plugged in (using the manifest file), then it appears the Android system gets the ACTION_USB_DEVICE_ATTACHED intent, and then since it knows your application wants to run in that situation, it actually sends your application the android.intent.action.MAIN intent. It never sends the ACTION_USB_DEVICE_ATTACHED action to your application because it thinks it already knows what your application wants to do in that situation.

I've just now identified the problem, and I think I have a solution, but I can tell you what I've found:

Even if your app is running and in the foreground, when you plug in the USB device and the Android system gets the ACTION_USB_DEVICE_ATTACHED intent, it will call onResume() in your activity.

Unfortunately, you cannot just do this:

@Override
public void onResume() {
    super.onResume();

    Intent intent = getIntent();
    Log.d(TAG, "intent: " + intent);
    String action = intent.getAction();

    if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
        //do something
    } 
}

Because the intent will come back as android.intent.action.MAIN, NOT ACTION_USB_DEVICE_ATTACHED.

An annoyingly, you also get android.intent.action.MAIN if you just leave the app, but don't unplug USB. I imagine putting the device to sleep and waking it back up will do the same thing.

So from what I have found, you can't get the intent directly, but it does appear that you can rely on onResume() being called when a USB device is plugged in, so the solution is to just check to see if USB is connected every time you get an onResume. You can also set a flag when USB is disconnected, because of course the USB disconnect intent fires just fine.

So in total, your broadcast receiver might look like this:

// BroadcastReceiver when remove the device USB plug from a USB port  
BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
         if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {                
        usbConnected=false;             
        }
    }
};

You'd have this inside of onCreate:

  // listen for new devices
 IntentFilter filter = new IntentFilter();
 filter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
 registerReceiver(mUsbReceiver, filter);

This goes inside of the activity tag in your manifest:

        <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"
            android:resource="@xml/device_filter" />

You'll have a device_filter.xml file in your /res/xml/ folder that looks like this:

<?xml version="1.0" encoding="utf-8"?>

<resources>
    <usb-device vendor-id="1027" product-id="24577" />  
    <usb-device vendor-id="1118" product-id="688" /> 
</resources>

(of course with whatever vendor IDs and product IDs you need)

And then your onCreate looks something like this:

@Override
public void onResume() {
    super.onResume();

    Intent intent = getIntent();
    Log.d(TAG, "intent: " + intent);
    String action = intent.getAction();


    if (usbConnected==false ) {
        //check to see if USB is now connected
    } 
}

I don't have specific code for checking to see if USB is connected as I actually haven't delved into that yet. I'm using a library that will just connect if it can, so for my application I can just start that loop and I'm good.

Its also probably important to set the launchmode of your activity in the manifest to "singleTask" to prevent it from running again when its already running, or else plugging in a USB device will just launch a second instance of your application!

So my whole activity tag in my manifest looks like this:

    <activity
        android:label="@string/app_name"
        android:name="com.awitness.common.TorqueTablet"
        android:theme="@android:style/Theme.Holo.NoActionBar.Fullscreen"
        android:screenOrientation="landscape"
        android:configChanges="orientation|keyboardHidden" 
        android:launchMode="singleTask"
        >
        <intent-filter >
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.HOME"/>
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter> 

        <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"
            android:resource="@xml/device_filter" />

    </activity>

Anyway, I hope this helps someone! I was surprised that I was unable to find a solution for this already!

Android – bypass android usb host permission confirmation dialog

I know it's a bit late, but still...

I had the same kind of problem and I think I've managed to solve it. There's a service that Android uses internally that allows to manage USB devices and accessories. This service is hidden from thrid party developers and is not documented. If you check the source code for UsbPermissionActivity you'll be able to figure out how that service is called. In order to call the service IUsbManager interface and ServiceManager class are employed. These are both hidden too, so you can't use them directly. But what you can do is to create their stubs with exactly the same names and in corresponding namespaces (packages). Then you'll be able to compile that code, while the runtime environment will use the real things.

The only requirement is that your application has to be a system one - that is it has to be located in /system/app/ directory. Since your device is rooted that shouldn't be a problem.

So you will have to add a package to your project: "android.hardware.usb" and put a file in it named "IUsbManager.java" with the following content:

package android.hardware.usb;

public interface IUsbManager extends android.os.IInterface
{
    /** Local-side IPC implementation stub class. */
    public static abstract class Stub extends android.os.Binder implements android.hardware.usb.IUsbManager
    {
        /** Construct the stub at attach it to the interface. */
        public Stub()
        {
            throw new RuntimeException( "Stub!" );
        }
        /**
         * Cast an IBinder object into an android.hardware.usb.IUsbManager interface,
         * generating a proxy if needed.
         */
        public static android.hardware.usb.IUsbManager asInterface( android.os.IBinder obj )
        {
            throw new RuntimeException( "Stub!" );
        }

        public android.os.IBinder asBinder()
        {
            throw new RuntimeException( "Stub!" );
        }

        public boolean onTransact( int code, android.os.Parcel data, android.os.Parcel reply, int flags ) throws android.os.RemoteException
        {
            throw new RuntimeException( "Stub!" );
        }

        static final int TRANSACTION_getDeviceList = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
        static final int TRANSACTION_openDevice = (android.os.IBinder.FIRST_CALL_TRANSACTION + 1);
        static final int TRANSACTION_getCurrentAccessory = (android.os.IBinder.FIRST_CALL_TRANSACTION + 2);
        static final int TRANSACTION_openAccessory = (android.os.IBinder.FIRST_CALL_TRANSACTION + 3);
        static final int TRANSACTION_setDevicePackage = (android.os.IBinder.FIRST_CALL_TRANSACTION + 4);
        static final int TRANSACTION_setAccessoryPackage = (android.os.IBinder.FIRST_CALL_TRANSACTION + 5);
        static final int TRANSACTION_hasDevicePermission = (android.os.IBinder.FIRST_CALL_TRANSACTION + 6);
        static final int TRANSACTION_hasAccessoryPermission = (android.os.IBinder.FIRST_CALL_TRANSACTION + 7);
        static final int TRANSACTION_requestDevicePermission = (android.os.IBinder.FIRST_CALL_TRANSACTION + 8);
        static final int TRANSACTION_requestAccessoryPermission = (android.os.IBinder.FIRST_CALL_TRANSACTION + 9);
        static final int TRANSACTION_grantDevicePermission = (android.os.IBinder.FIRST_CALL_TRANSACTION + 10);
        static final int TRANSACTION_grantAccessoryPermission = (android.os.IBinder.FIRST_CALL_TRANSACTION + 11);
        static final int TRANSACTION_hasDefaults = (android.os.IBinder.FIRST_CALL_TRANSACTION + 12);
        static final int TRANSACTION_clearDefaults = (android.os.IBinder.FIRST_CALL_TRANSACTION + 13);
        static final int TRANSACTION_setCurrentFunction = (android.os.IBinder.FIRST_CALL_TRANSACTION + 14);
        static final int TRANSACTION_setMassStorageBackingFile = (android.os.IBinder.FIRST_CALL_TRANSACTION + 15);
    }

    /* Returns a list of all currently attached USB devices */
    public void getDeviceList( android.os.Bundle devices ) throws android.os.RemoteException;
    /* Returns a file descriptor for communicating with the USB device.
         * The native fd can be passed to usb_device_new() in libusbhost.
         */
    public android.os.ParcelFileDescriptor openDevice( java.lang.String deviceName ) throws android.os.RemoteException;
    /* Returns the currently attached USB accessory */
    public android.hardware.usb.UsbAccessory getCurrentAccessory() throws android.os.RemoteException;
    /* Returns a file descriptor for communicating with the USB accessory.
         * This file descriptor can be used with standard Java file operations.
         */
    public android.os.ParcelFileDescriptor openAccessory( android.hardware.usb.UsbAccessory accessory ) throws android.os.RemoteException;
    /* Sets the default package for a USB device
         * (or clears it if the package name is null)
         */
    public void setDevicePackage( android.hardware.usb.UsbDevice device, java.lang.String packageName ) throws android.os.RemoteException;
    /* Sets the default package for a USB accessory
         * (or clears it if the package name is null)
         */
    public void setAccessoryPackage( android.hardware.usb.UsbAccessory accessory, java.lang.String packageName ) throws android.os.RemoteException;
    /* Returns true if the caller has permission to access the device. */
    public boolean hasDevicePermission(android.hardware.usb.UsbDevice device) throws android.os.RemoteException;
    /* Returns true if the caller has permission to access the accessory. */
    public boolean hasAccessoryPermission( android.hardware.usb.UsbAccessory accessory ) throws android.os.RemoteException;
    /* Requests permission for the given package to access the device.
         * Will display a system dialog to query the user if permission
         * had not already been given.
         */
    public void requestDevicePermission( android.hardware.usb.UsbDevice device, java.lang.String packageName, android.app.PendingIntent pi ) throws android.os.RemoteException;
    /* Requests permission for the given package to access the accessory.
         * Will display a system dialog to query the user if permission
         * had not already been given. Result is returned via pi.
         */
    public void requestAccessoryPermission( android.hardware.usb.UsbAccessory accessory, java.lang.String packageName, android.app.PendingIntent pi ) throws android.os.RemoteException;
    /* Grants permission for the given UID to access the device */
    public void grantDevicePermission( android.hardware.usb.UsbDevice device, int uid ) throws android.os.RemoteException;
    /* Grants permission for the given UID to access the accessory */
    public void grantAccessoryPermission( android.hardware.usb.UsbAccessory accessory, int uid ) throws android.os.RemoteException;
    /* Returns true if the USB manager has default preferences or permissions for the package */
    public boolean hasDefaults( java.lang.String packageName ) throws android.os.RemoteException;
    /* Clears default preferences and permissions for the package */
    public void clearDefaults( java.lang.String packageName ) throws android.os.RemoteException;
    /* Sets the current USB function. */
    public void setCurrentFunction( java.lang.String function, boolean makeDefault ) throws android.os.RemoteException;
    /* Sets the file path for USB mass storage backing file. */
    public void setMassStorageBackingFile( java.lang.String path ) throws android.os.RemoteException;
}

Then another package: "android.os" with "ServiceManager.java":

package android.os;

import java.util.Map;

public final class ServiceManager
{
    public static IBinder getService( String name )
    {
        throw new RuntimeException( "Stub!" );
    }

    /**
     * Place a new @a service called @a name into the service
     * manager.
     * 
     * @param name the name of the new service
     * @param service the service object
     */
    public static void addService( String name, IBinder service )
    {
        throw new RuntimeException( "Stub!" );
    }

    /**
     * Retrieve an existing service called @a name from the
     * service manager.  Non-blocking.
     */
    public static IBinder checkService( String name )
    {
        throw new RuntimeException( "Stub!" );
    }

    public static String[] listServices() throws RemoteException
    {
        throw new RuntimeException( "Stub!" );
    }

    /**
     * This is only intended to be called when the process is first being brought
     * up and bound by the activity manager. There is only one thread in the process
     * at that time, so no locking is done.
     * 
     * @param cache the cache of service references
     * @hide
     */
    public static void initServiceCache( Map<String, IBinder> cache )
    {
        throw new RuntimeException( "Stub!" );
    }
}

Note that interfaces of these classes may change depending on the version of Android. In my case the version is 4.0.3. So if you have another version of Android and this code doesn't work you will have to check the source code for your particular version of OS.

Here's an example of using the service to grant permissions to all FTDI devices:

import java.util.HashMap;
import java.util.Iterator;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.hardware.usb.IUsbManager;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbManager;
import android.os.IBinder;
import android.os.ServiceManager;

public class LaunchReceiver extends BroadcastReceiver
{
    public void onReceive( Context context, Intent intent )
    {
        String action = intent.getAction();
        if( action != null && action.equals( Intent.ACTION_BOOT_COMPLETED ) )
        {
            try
            {
                PackageManager pm = context.getPackageManager();
                ApplicationInfo ai = pm.getApplicationInfo( YOUR_APP_PACKAGE_NAMESPACE, 0 );
                if( ai != null )
                {
                    UsbManager manager = (UsbManager) context.getSystemService( Context.USB_SERVICE );
                    IBinder b = ServiceManager.getService( Context.USB_SERVICE );
                    IUsbManager service = IUsbManager.Stub.asInterface( b );

                    HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
                    Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
                    while( deviceIterator.hasNext() )
                    {
                            UsbDevice device = deviceIterator.next();
                            if( device.getVendorId() == 0x0403 )
                            {
                                service.grantDevicePermission( device, ai.uid );
                                service.setDevicePackage( device, YOUR_APP_PACKAGE_NAMESPACE );
                            }
                    }
                }
            }
            catch( Exception e )
            {
                trace( e.toString() );
            }
        }
    }
}

One more thing - you will have to add the following permission to your manifest (Lint might not like it but you can always change severity level in your project's properties):

<uses-permission android:name="android.permission.MANAGE_USB" />

Best Answer

Related Solutions

Java – Android 3.1 USB-Host – BroadcastReceiver does not receive USB_DEVICE_ATTACHED

Android – bypass android usb host permission confirmation dialog

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