Shantanu's Technophilic Musings

Camera LED As Flashlight on Non-Rooted Android Phones

Shantanu Goel — Fri, 30 Jul 2010 09:31:08 +0000

We all know that Android does not allow the camera LED to be controlled directly from apps and hence, you cannot use the camera LED as a Torch or Flashlight unless you are rooted. There are many flashlight apps on the Android Market Place but none of them will work for you if you don’t have a rooted phone. BUT this changed recently. I use a brilliant app called “quick settings” which keeps an icon in the notification bar and I can pull it down and change any settings without leaving other apps. It has a flashlight function but so far it used to work by turning on the screen with a white screen, which was a less than ideal solution. I upgraded to the latest version a few days ago (1.9.4 p1). While messing around with the settings, I wandered across the flashlight settings which allows you to choose what kind of flashlight you want. Now, I’m not sure whether this setting was present earlier or not but I decided to give it a try and chose LED instead of screen (Screenshot below):

Once done, I went back to the main screen and pressed the flashlight icon in the top right (Screen shot below) and voila! my camera LED switched on. I’m a happy camper now as this is a life saver many times. Try this out for yourself by searching for “Quick Settings” in the market and let me know if it works on your phone too (mine is a nexus one).

Firefly / sqlite error “unable to open database file” Solution

Shantanu Goel — Mon, 26 Jul 2010 18:11:40 +0000

Recently I came across a weird error while trying to run firefly itunes server (mt-daapd) on my router (Asus wl-500w). It had something to do with sqlite and gave a vague message “Unable to open database file”. After going bonkers for a short time, I solved it and this is how.

One of my hard disks crashed recently and unfortunately it was the one I had connected to my router to serve media to me all over the house (through PS3/laptop) or when I travel (through laptop/phone). I had all the data backed up but somehow didn’t preserve the firefly server. I rebuilt the server from source using my own guide (Thank God I did it. I wouldn’t have been able to preserve my sanity finding all that out the hard way again.). But after doing all the installation and reconfiguration, it gave me a weird error “unable to open database file” every time and exited. I checked the permissions on the songs3.db file (in /opt/var/cache/mt-daapd for me) and made it writable by all but the issue persisted. I changed its ownership to the user under which firefly was running but the issue was still there. Finally I found that the server (or maybe its an sqlite thing) was trying to create a temp file in the cache directory for the transactions and since the user with which it was started, didn’t own the directory it wasn’t able to create the file in it.

So, the fix: I did a “chown /opt/var/cache/mt-daapd” on it and voila! the problem was fixed. I am a happy man now since I own a new android phone since last time and now able to stream all my music to my phone through itunes (daap protocol) server over an ssh tunnel

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Tags: Asus, Asus WL-500W, daap, daap protocol, firefly, itunes daap media server, mt-daapd, sqlite, sqlite error unable to open database file

Android App Wi-Fi Keep Alive updated to 1.4.1

Shantanu Goel — Thu, 22 Jul 2010 16:58:07 +0000

Update: Made a minor update for a small bug that can make wi-fi keep reconnecting in quick succession.

Pushed out a new update to my Android App Wi-Fi Keep Alive today. This update brings in another work around for the issue where the wi-fi is alive on the phone and it is also connected to the network but is somehow unable to send/receive any packets to the network. The new work around will automatically re-associate your phone with the wi-fi router if it detects such a situation. This seems to make it work properly again for sometime. When it fails again, the workaround kicks in automatically again. This is not an ideal “fix” as such because streaming apps like Pandora radio etc might have a hiccup because of this but it is unavoidable as of now and atleast the notifications for mails and other things etc will work fine because this state stops even the mobile data network from taking over since the phone perceives that wi-fi is connected but is not working actually.

The other things include support for small screen devices like Xperia X10 mini, some optimizations for size and speed, some icon sizes and UI tweaks for compatibility with different screen sizes and android versions. Please try it out from the market as usual and let me know how it goes. You can find the details and QR code for downloading etc here: Wi-Fi Keep Alive

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Tags: Android, android apps, android wi-fi sleep policy, Pandora stops on sleep android, Wi-Fi Keep Alive

Cannot Change Channel Problem With Asus WL-500W

Shantanu Goel — Tue, 13 Jul 2010 12:16:44 +0000

Recently I found an issue with my asus wl-500w wi-fi router that I wasn’t able to change the channel on which it was transmitting. I moved to a new location which was totally jam-packed with other wi-fi networks using same channel as mine which was hampeing my connection. I tried for umpteen number of times. Changing the channel through the web configuration did not give any error but I found that it was still transmitting at channel 1. I confirmed by checking on the “Status & Log” page, checking the logs, and running “wl status” command through ssh and they all confirmed that it was transmitting at channel 1 only, no matter what I set it to in the configuration. I even opened an issue in the firmware project for the custom firmware (by oleg and lly) that I am using but they weren’t able to help me as the wi-fi drivers are binary only.

But by sheer chance, I stumbled upon the solution finally by trial and error. The solution is that you should set the “Bandwidth” to 20 MHz in wi-fi configuration if you are using 802.11 G. If you set it to 40 MHz then it gets stuck somehow but as soon as I changed it to 20 MHz, I was able to see the channel change immediately after reboot. Here is the screenshot of the page where you can find this setting.

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Tags: Asus, Asus WL-500g, Asus WL-500W, asus wl-500w channel, Asus WL-500W firmware, Asus WL-500W hacks, lly, oleg, oleg custom firmware, oleg firmware, wi-fi channel

Mute (or Answer) Skype Calls with BT Headset Button in Linux

Shantanu Goel — Thu, 08 Jul 2010 18:31:55 +0000

Skype on linux works great but the problem that I faced was that it does not handle the buttons on the bluetooth headsets. My wife uses skype to call into her work related conference calls and was pretty frustrated that she had to keep sitting in front of my laptop (her laptop didn’t allow to install skype) just to switch mute on and off. So, I whipped up this little trick to do so. Here is how:

1. First I looked at the skype API (pretty simple, based on dbus). Also found a sample script somewhere that allowed to answer and hang up calls through skype API.

2. Modified the script to switch the mute on and off instead of answering/hanging up. Script can be downloaded at the end of this article. You can also modify it to take some other action that you want.

3. Install “blueman”. If you are using Ubuntu, just type “sudo apt-get install blueman” in shell.

4. Once blueman is installed and you have done your headset pairing etc, right click on the blueman icon in the system tray and click on “Local Services”.

5. In local services, click on headset tab and you can see a input box where you can give the path of a program/script which will be run whenever the “answer button” on the headset is pressed. This is important to note that blueman only supports the answer button and nothing else and I didn’t have the inclination to develop a full-fledged AVRCP compliant program to capture other buttons as all I was interested in mute functionality. You can see the screenshot of this below:

6. Make sure that you give the path where you saved the script that you downloaded in step 4 and you are all set now. Make a call and click on the answer button of your headset to see the magic happen

Let me know if you have your own hacks like this or know of a way to have a full fledged capturing of all headset buttons.

Download:	Skype Bluetooth Mute Button Script
Version:	0.1
Updated:	July 8, 2010
Size:	990 bytes
Hits:	59

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Tags: blueman, headset button skype linux, mute calls skype linux, skype, skype linux

BadTokenException Error In Android Dialog

Shantanu Goel — Thu, 08 Jul 2010 11:24:14 +0000

If you are creating a custom Dialog for Android, and following the Android Developers’ Creating Dialogs tutorial, then most likely you would have faced a Force Close with this exception showing up in logcat. I did too. Although I figured it out quickly, it might not be easy to find out for many, so posting it here for reference. Basically, the code given in the tutorial goes something like this:

Context mContext = getApplicationContext();
Dialog dialog = new Dialog(mContext);

dialog.setContentView(R.layout.custom_dialog);
dialog.setTitle("Custom Dialog");

TextView text = (TextView) dialog.findViewById(R.id.text);
text.setText("Hello, this is a custom dialog!");
ImageView image = (ImageView) dialog.findViewById(R.id.image);
image.setImageResource(R.drawable.android);

All looks well, but when you execute it, you will get a Force Close. The error appearing in logcat would be something like this:

Uncaught handler: thread main exiting due to uncaught exception
android.view.WindowManager$BadTokenException: Unable to add window — token null is not for an application

It isn’t apparent immediately that what is causing this error. The very first line in the code “Context mContext = getApplicationContext();” is the culprit.

Solution: Just replace “getApplicationContext()” with “this” (i.e. “Context mContext = this;” ) and it will work fine.

Explanation: As to why this is exactly an issue, I’m a bit fuzzy about it myself but this much I’m sure that the contexts that you get with getApplicationContext and this are different. On reading about this function from Android SDK help:

Return the context of the single, global Application object of the current process. This generally should only be used if you need a Context whose lifecycle is separate from the current context, that is tied to the lifetime of the process rather than the current component.

I think this would mean is that getApplicationContext returns a context which is for the application itself and not the activity, while “this” would give you the context of the activity in which you are creating the dialog. I think since it is the activity which is associated with the UI (and for whom the window has been created), using the application context would have caused the crash here.

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Tags: Android, Android Dialogs, BadTokenException Android, getApplicationContext Android, Programming

Android App: Wi-Fi Keep Alive Updated to 1.2.0

Shantanu Goel — Sat, 03 Jul 2010 22:46:36 +0000

Just finished uploading the new version 1.2.0 of my android app Wi-Fi Keep Alive to the Android market. This version has a lot of optimizations and also a few workarounds to overcome the issues few guys were facing with Android’s in-built handling of wi-fi sleep policies. Please check out the Wi-Fi Keep Alive Home Page for more details and download links etc.

Changes done in this version:

* Added workarounds to take care of sleep policies not working on some phones

* Optimized the code a bit for faster operations

* Added Configuration screens to widgets (pops up whenever widget is added)

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Tags: Android, android apps, android wi-fi sleep policy, downloads, phone, Wi-Fi Keep Alive, widget

Android App: Wi-Fi Keep Alive

Shantanu Goel — Mon, 28 Jun 2010 15:25:48 +0000

I just wrote my second Android App. This again was to scratch an itch of mine but it seems to have become a bit popular already (My first app “Quick Sync Settings” did around 400 downloads in 20 days but this one has already surpassed that in less than one day). This app basically allows you to change the wi-fi sleep policy on android so that you can keep your wi-fi connected even if the phone goes to sleep (i.e. screen turns off). What’s more is that I’ve added a widget to it so you don’t even have to go into the app. Just tap on the widget to cycle through the settings. Please try it out here: Android Wi-Fi Keep Alive and let me know if you like it

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Tags: Android, android apps, downloads, phone, Wi-Fi Keep Alive, widget

Android vs iPhone: Security Models

Shantanu Goel — Fri, 25 Jun 2010 22:02:49 +0000

Android and iPhone OS (iOS) have been at loggerheads for quite some time now. This is a take on which has a better security model to protect its users. I thought of writing it up because there have been a lot of discussions around me lately about which platform is more secure and I keep repeating the same points over and over at every one of them, so thought that in future I’ll just point them to this page

Disclaimer:

A. I don’t guarantee this post to be absolutely correct as I’m no security researcher or expert but I do have some interest in this field and I’ve been a developer for some time now on different architectures and OSs especially at OS/driver level and that too in the mobile devices field, so I “might” actually be right about a few things here and there..

B. I’m an android user myself but not of the fanboy variety. I’ll be happy to switch camps any day I get something that appeals to me better. I have love and hate points for almost all platforms available but I’m using android because “for me” it’s love points slightly outnumber the hate points.

OK, on with the points then. Here is the table that I created for this showing points I considered and which side wins each. Don’t start flaming me though just by seeing the table I will be discussing the points as well below it.

**Android vs iPhone: Security Models**
	Android	iPhone
Distribution Medium Security
Approval Process	NA	NA
Phishing	Lose	Win
Local Security
Permissions	Win	Lose
Environment/Sandbox	Tie	Tie
Open vs Close	Slight Win	Lose
App Development Model	Slight Win	Lose
Damage Control	Tie	Tie
Summary	?	?

1. Distribution Medium Security: Apple vets every application that is put on the app store while Google’s Market Place is unrestricted. How does this affect you security wise?

a. Approval Process: The biggest myth is that the vetting process is what will save you from malware on app store. IT WON’T. The Apple app approval process isn’t defined anywhere but in general it just states that it checks for apps to do what they say they will do. But they don’t check the source code of the apps and static analysis of binaries can only take you so far (Heck, they have even been inept at catching a whole lot of apps that were using their disallowed private apis which can be found easily using simple tools) . So, anyone actually wanting to write a malware can do it trivially by making the malicious code to run after the app has been approved. The trigger could be time based or could even be done over the web remotely. The app could even have encrypted payloads or download new pieces of code over the web and run them. So, we can safely say that approval process is something that can’t make things secure for you that way.

Result: No one wins

b. Phishing: This is where App store can protect you if someone put an app claiming to be from someone that it isn’t. e.g. Someone could make an app that claims to be from “Bank of America”. In apple’s case, I’m 99.99% sure that the app won’t pass the screening but in Android’s case, there won’t be any hassles for it to reach the marketplace. It could be pulled soon after as google learns about it but still even one person’s damage here is much more than what would have happend on iPhone.

Result: iPhone wins

2. Local Security: What about the security in the OS itself once an app is on your phone? This is an important question because 1.) As I noted above, Apple’s app screening process isn’t robust enough to catch malware 2.) People can bypass the official distribution medium easily. Android allows to install apps from other sources on most phones by just enabling an option and a huge number of people jailbreak their iPhones and get/use this capability.

a. Permissions: On Android, an app has to explicitly declare what capabilities/data of the phone it wants to access/use and the user has to explicitly give it those permissions before it is allowed to install, irrespective of from where/how this app is being installed. So, it works even if you are installing the app from your SD card and even if you have rooted your phone. On iPhone, there is no such mechanism of restricting apps. All apps are equal and can access a lot of resources unhindered without the user knowing. So, while installing a single player only game on android you can immediately be suspicious if the app is asking for internet connection or access to your contacts data but on iPhone you will not come to know about this.

Result: Android wins

b. Environment: On both platforms, the apps run in their own sandboxes with unique uuids

Result: Tie

3. Open vs Closed: Most of the Android code is open source while for iOS, only darwin kernel and some other things like webkit etc are open source. Now, this in itself doesn’t gurantee to make Android secure but its code does get a lot of scrutiny from open source community as well as lot of other big name companies with commercial interests in Android which allows it to find and fix more bugs and loopholes than iPhone can.

Result: Slight win for Android

4. App development model: Most apps for Android are written in java while those in iPhone are written in C/Objective-C. While I’m myself a big time C lover (Majority of my coding is in C/CPP) but it is indeed a very unforgiving language where you need to be very careful with what you write and has much greater chances of exploits, .e.g, Buffer overflows, as compared to java (Interestingly, all the jailbreaks for iPhone OS have been done using such exploits and have been made available day 0/day 1 mostly.)

Result: Slight win for Android

5. Damage Control: What if an app actually got through everything on any of these platforms and started spreading? Both of these platforms have kill switches in the hands of Google/Apple which they can use to remove such malicious apps from the users’ phones remotely.

Result: Tie

Summary: Well, there is no clear winner. Apple is quite good when it comes to protecting you from phishing (though that advantage goes away if you jailbreak and use alternative means to install apps) and Android has a real sound local security system (though it also has the flaw that users might not always understand why an app is requesting a certain critical permission and install it anyways). So, take your pick and let me know what you picked and please do tell me if I’m wrong in any of my points or missed out on something that needs to be compared.

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Tags: Android, Android vs iPhone, app development, Apple, application, code, community, google, iPhone, malware, mobile devices, open source, permissions, root, security, security models

How To Debug Android Widgets

Shantanu Goel — Sun, 13 Jun 2010 18:42:42 +0000

For most new android app developers (like me), it is a bit puzzling how to debug the android widgets or how to put a breakpoint in an android widget code. For normal applications, it is quite simple as when you press “debug” on the eclipse toolbar, it launches the emulator (or connects to existing emulator/device), syncs your application and launches its main activity and puts the control in your hands if you have put a breakpoint. For widgets, it seems a bit tricky because there is no activity to be launched, so eclipse just syncs your widget’s apk and installs it and that’s it. So, is it possible or not to debug widget code? and if yes, then is it very difficult? Fortunately, it is possible and very easy to do but just slightly less intuitive and I couldn’t find any information about it at Android developers website and learnt it by just fumbling around for a few minutes so thought of posting here for the benefit of other newbies like me.

So, all you need to debug your widget code is almost same as what you do for normal applications. Just follow the below steps:

1. Press “debug” on the eclipse menu (or “run” it doesn’t seem to matter)

2. Once the widget apk is sync’ed and installed onto your emulator/device, switch your eclipse workspace to DDMS mode. You can either do this by pressing the “DDMS” labeled button on your top right corner or if you can’t find it, then do it by going to “Window->Open Perspective->DDMS”.

3. Select the process name of your widget from the list of processes shown. By default, this list appears at top left of DDMS window. (See screenshot below). If you can’t see your widget’s process name in the list, it is possible that the widget is not added to the home screen yet. So, do so.

4. Press the green debug button above the process list (See screenshot below)

5. And that’s it. Now, if you had put a breakpoint in the code, do something that executes that piece of the code.

Click To Enlarge

Let me know if this helped you out or if you see anything that I missed out. Happy coding

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Tags: Android, android coding, android programming, android widget breakpoint, DDMS, debug android widgets, eclipse, widgets

Shantanu's Technophilic Musings

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