CODEWITHSUNDEEP
javaandroid
Ivo Renkema
Ivo Renkema

Reputation: 2198

try ... catch is not catching IllegalArgumentException

In an open-source Camera App, I have a crash at the following code

try {
    // crash happens in next line:
    PtpUsbConnection connection = new  PtpUsbConnection(usbManager.openDevice(device), in, out,
                      device.getVendorId(), device.getProductId());
    camera = new EosCamera(connection, listener, new WorkerNotifier(context));
}
catch (IllegalArgumentException e) {
    Log.i(TAG, "IllegalArgumentException: camera was switched off? "+ e.getMessage());
    e.printStackTrace();
    return false;
}
catch (Exception e) {
    Log.i(TAG, "Exception: camera was switched off? "+ e.getMessage());
    e.printStackTrace();
    return false;
}

The crash produces the following log

02-25 10:41:14.698    9238-9238/com.remoteyourcam.usb E/UsbManager﹕ exception in UsbManager.openDevice
java.lang.IllegalArgumentException: device /dev/bus/usb/001/008 does not exist or is restricted
        at android.os.Parcel.readException(Parcel.java:1469)
        at android.os.Parcel.readException(Parcel.java:1419)
        at android.hardware.usb.IUsbManager$Stub$Proxy.openDevice(IUsbManager.java:373)
        at android.hardware.usb.UsbManager.openDevice(UsbManager.java:308)
        at com.remoteyourcam.usb.ptp.PtpUsbService.connect(PtpUsbService.java:238)
        at com.remoteyourcam.usb.ptp.PtpUsbService.initialize(PtpUsbService.java:135)
        at com.remoteyourcam.usb.MainActivity.onStart(MainActivity.java:232)
        at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1171)
        at android.app.Activity.performStart(Activity.java:5413)
        at android.app.Activity.performRestart(Activity.java:5469)
        at android.app.Activity.performResume(Activity.java:5474)
        at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2945)
        at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2984)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1335)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:149)
        at android.app.ActivityThread.main(ActivityThread.java:5257)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:788)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:604)
        at dalvik.system.NativeStart.main(Native Method)

There is a reproducible sequence of events which causes the crash. Specifically: switching of the camera on the USB bus when the App (apparently) does not foresee the possibility.

I was hoping to simply catch this Exception and then ignore it.

However, even though the code explicity catches IllegalArgumentException and also (for good measure) the general Exception, the App simply continues to crash.

Why is my IllegalArgumentException not being caught?

---- update:

The openDevice() method is part of Android Library. It actually seems to handle Exception.

Here are my imports

package com.remoteyourcam.usb.ptp;

import java.util.Map;

import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.hardware.usb.UsbConstants;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbEndpoint;
import android.hardware.usb.UsbInterface;
import android.hardware.usb.UsbManager;
import android.os.Handler;
import android.util.Log;

import com.remoteyourcam.usb.AppConfig;
import com.remoteyourcam.usb.ptp.Camera.CameraListener;
import com.remoteyourcam.usb.ptp.PtpCamera.State;

---- update 2:

This is the openDevice() implementation I see in Android 18. As far as I can tell, it handles a general Exception

/**
 * Opens the device so it can be used to send and receive
 * data using {@link android.hardware.usb.UsbRequest}.
 *
 * @param device the device to open
 * @return a {@link UsbDeviceConnection}, or {@code null} if open failed
 */
public UsbDeviceConnection openDevice(UsbDevice device) {
    try {
        String deviceName = device.getDeviceName();
        ParcelFileDescriptor pfd = mService.openDevice(deviceName);
        if (pfd != null) {
            UsbDeviceConnection connection = new UsbDeviceConnection(device);
            boolean result = connection.open(deviceName, pfd);
            pfd.close();
            if (result) {
                return connection;
            }
        }
    } catch (Exception e) {
        Log.e(TAG, "exception in UsbManager.openDevice", e);
    }
    return null;
}

Upvotes: 2

Views: 2119

Answers (2)

Matthew
Matthew

Reputation: 58

The same situation I got as you with this source code, I found a trick that avoid crash. Just fix your code 

try {
    // crash happens in next line:
    PtpUsbConnection connection = new  PtpUsbConnection(usbManager.openDevice(device), in, out,
                      device.getVendorId(), device.getProductId());
    camera = new EosCamera(connection, listener, new WorkerNotifier(context));
}
catch (IllegalArgumentException e) {
    Log.i(TAG, "IllegalArgumentException: camera was switched off? "+ e.getMessage());
    e.printStackTrace();
    return false;
}
catch (Exception e) {
    Log.i(TAG, "Exception: camera was switched off? "+ e.getMessage());
    e.printStackTrace();
    return false;
}

to

try {
    // crash happens in next line:
    UsbDeviceConnection udc = usbManager.openDevice(device);
    if (udc != null){
        PtpUsbConnection connection = new  PtpUsbConnection(udc, in, out,
                      device.getVendorId(), device.getProductId());
        camera = new EosCamera(connection, listener, new WorkerNotifier(context));
    }

}
catch (IllegalArgumentException e) {
    Log.i(TAG, "IllegalArgumentException: camera was switched off? "+ e.getMessage());
    e.printStackTrace();
    return false;
}
catch (Exception e) {
    Log.i(TAG, "Exception: camera was switched off? "+ e.getMessage());
    e.printStackTrace();
    return false;
}

It works for me!

Upvotes: 0

mach
mach

Reputation: 8395

The Exception is happening in another thread.

You are initializing and dispatching work to another thread asynchronously. Your code only catches exceptions in dispatching the Parcel to the remote Service.

For more information about remote procedure calls in Android you might want to read Deep Dive into Binder.

Upvotes: 2

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