Question or Comment?

Android / Barcode Scanner

Why does Barcode Scanner want access to ...

... my contacts?

QR Codes and Data Matrix codes can encode contact information. Upon scanning such a code, you will be prompted to add the contact information to your contacts list. In addition, Barcode Scanner can encode a contact as a QR Code and present it on-screen, so that a friend can point their phone at your screen to transfer that contact. This is why the app requests permission to write and read contacts. They are not used in any other way.

... my browser history and bookmarks?

Just like contacts, you can share a bookmark with a friend by encoding the URL as a QR Code. It is then shown on screen for him or her to scan with their phone. That's the only thing we use them for.

... my SD card?

You can use Barcode Scanner to email a generated QR code or your scan history. To do this, the barcode image / history CSV file must first be written to device storage, which is why the permission is needed. As a bonus, this makes this output available for retrieval from your SD card directly. It is not used for any other purpose.

... my WiFi settings?

QR codes can encode the user name, password, etc. for a WiFi network so that you don't have to type them into your phone. To do this, the application needs to be able to change WiFi settings.

I don't get prices from Barcode Scanner, or get very high prices, for some products

This application does not maintain or provide any product information, so these are not problems with Barcode Scanner itself. It links to Google Product Search and Web Search; contact Google with suggestions.

Note that common household items are often available for purchase online, but in bulk quantity. This is one reason that results for the product's price seem high: they are not for individual items. Again, this is not an issue with Barcode Scanner itself.

The app won't download or install

These are functions of the Market application and the Android platform, and outside the application's control. We do get some reports of stuck downloads which can be fixed by rebooting the phone. If that doesn't help, please contact the phone manufacturer or your carrier.

I can't uninstall the Barcode Scanner application

Some manufacturers put Barcode Scanner into the "firmware" of the phone, which means it is not uninstallable. This is an issue to take up with manufacturers or carriers. Sorry, we can't do anything about this.

I see only a black screen on my LG Optimus series device

These devices appear to have a bug wherein selecting any preview size that the device says it supports that does not match the screen size results in no camera display. The app chooses a higher resolution for better scanning. It has been confirmed as a device problem. A future version may include a workaround option for these devices, to force it to use screen size preview only.

You can always return to the previous version by uninstalling your copy, and installing version 3.72 from this link: http://code.google.com/p/zxing/downloads/detail?name=BarcodeScanner3.72.apk

My Archos tablet won't run the application, failing with an error related to landscape orientation

The app is landscape-orientation only, and specifies this in AndroidManifest.xml with <uses-feature> tag for android.hardware.screen.landscape. All Android 3.0 devices and earlier must allow apps requiring either orientation, and any device supporting landscape orientation should allow such an app. However, some Archos tablets reject such apps, even though they run Android 2.x and do support landscape apps. They show themselves as compatible in Market, which is correct. It is an Archos bug affecting any landscape-only app and there is no workaround available.

The front light goes on and off

This is a bug in some devices that turns off the front light during auto-focus in "torch" mode. The API docs show that it should remain on: http://developer.android.com/reference/android/hardware/Camera.Parameters.html#FLASH_MODE_TORCH There is no known workaround.

iOS / Barcodes

What version of ZXing should I use with iOS?

ZXing 1.7 has support for iOS 4 and later. ZXing does not support iOS versions prior to iOS 4. You may also want to try the subversion trunk. It's generally very stable.

What is the minmum iOS version for ZXing?

Only iOS 4 and newer can be used for live screen capture and decoding. The iOS APIs for live screen capture were only added in iOS 4. Prior to iOS 4, a "private" iOS API (UIGetScreenImage) was used by ZXing and similar apps and libraries. Apple will not allow the use of this API in new submissions to the iOS app store and support for it has been dropped from ZXing.

Why does my application decode okay in debug mode on iOS but not in release mode?

You're compiling with an old version of llvm-gcc or clang. If you use Xcode 4.2, either supported compiler should be fine with optimizations turned on. Older compilers, shipped with Xcode 4.1 and earlier, had an optimization bug in llvm that miscompiled ZXing. If you are using Xcode 4.1 or older, you should use gcc to compile ZXing, not llvm-gcc or clang.

Why don't 1D codes work on iOS devices?

An initial port of the Java code to C++ for 1D codes was done some time ago but has not been actively maintained. Results generated by this code are not comparable in quality or stability to the Java code. Because of this, it is disabled by default in the iOS classes. Contributors interested in improving and maintaining this code are welcome. It's not particularly hard; the Java code is actively maintained and not very difficult to port. The need is for someone with sufficient interest/motivation.

Is there a QR encoder for C++/iOS?

Not currently. There are several open source encoders that are used by people using ZXing but they each have their own history/license so can't be added to ZXing. There have been discussions about porting the Java encoder to C++ but no one has gotten around to it.

See discussion in the group for pointers to alternatives.