Eclipse ADT: 'Unable to open sync connection!'

Sometimes, you get this wierd looking error on eclipse while working/developing on your phone.

[2010-10-12 09:36:48 - myapp] java.io.IOException: Unable to open sync connection!
[2010-10-12 09:36:48 - myapp] Launch canceled!

You have tried the following (but in vain!):
1. Disconnecting/connecting the USB cable.
2. Restarting eclipse.
3. Restarting adb daemon.
4. Restarting your computer!


Even after this if the problem persists. Just disable/enable 'USB debugging' on your phone.
This should most of the times solve this issue.

How to request 'super user' permission from your app?

NOTE: This blog assumes that you have installed Superuser application installed on your device! Also, I'm not responsible for any bricked devices!

Process p;
try {
    p = Runtime.getRuntime().exec("su");
}
catch(IOException e) {
    e.printStackTrace();
}

This will pop up a window from 'Superuser' application which will ask user to whether allow your app to be given 'su' permissions or not. Users can either 'Allow' or 'Deny' and also set 'Remember this option' on this window.

Hope this helps!

AdbCommandRejectedException!

Sometimes, adb goes crazy on my Win7. If I open 'ddms' (to view logcat messages), I wont see any messages at all! If I look into the 'Command Window', I see the above exception being raised in it. Apparently, the work-around this is to do the following:

1. Un-plug the USB cable.
2. Kill the adb-server (adb kill-server)
3. Start the adb-server (adb start-server)
4. Plug in the USB

 Hope this helps!

Camera shutter sound on CM7!

Due to legal issues in some countries (see this issue) cyanogenmod doesn't support any settings for enabling/disabling camera shutter sound (It is enabled by default!). However, there's a system property which one can set in order to turn off the shutter sound. But, unfortuantely for this you need to install android SDK on your system and plug USB cable to your phone and connect it to your PC. (Also, do not forget to 'enable USB debugging'!!).

  adb shell setprop persist.camera.shutter.disable 1

NOTE:

 I'm not responsible for any damages/law-suites caused (whatsoever), by disabling the shutter sound of your phone's camera!

Measuring read/write BW of sdcard(s) on your android phones

I needed a quantitative way to measure the performance of the sd-card on my LG Optimus 2X. Hence I wrote the tool 'sd-speed'. Currently, this tool is supported only on linux and windows platforms. The project is hosted on github at the following location: 'git@github.com:teju85/sd-speed.git'. I have released it with the WTFPL (do What The Fuck you want to Public License).

Here are the results of running my program on my 'external sd-card', 'internal sd-card' and on 'phone memory' respectively: (Phone: LG O2X, CM7)

External sd-card

$ ./sdCardSpeedTest.sh /mnt/sdcard
NOTE: Test might take about 5-10 min depending on your sd-card speed!
      Please be patient during this time...

Evaluating write-BW...
100000000 bytes transferred in 26.371 secs (3792044 bytes/sec)
100000000 bytes transferred in 19.656 secs (5087505 bytes/sec)
100000000 bytes transferred in 20.697 secs (4831618 bytes/sec)
100000000 bytes transferred in 20.086 secs (4978592 bytes/sec)
100000000 bytes transferred in 53.975 secs (1852709 bytes/sec)
100000000 bytes transferred in 28.934 secs (3456141 bytes/sec)
Write BandWidth: 3.81448 MBps

Evaluating read-BW...
100000000 bytes transferred in 18.844 secs (5306728 bytes/sec)
100000000 bytes transferred in 17.818 secs (5612302 bytes/sec)
100000000 bytes transferred in 17.331 secs (5770007 bytes/sec)
100000000 bytes transferred in 17.301 secs (5780012 bytes/sec)
100000000 bytes transferred in 17.306 secs (5778342 bytes/sec)
100000000 bytes transferred in 17.310 secs (5777007 bytes/sec)
Read BandWidth: 5.40803 MBps

Cleaning up all the temporary files...

Internal sd-card

$ ./sdCardSpeedTest.sh /mnt/emmc
NOTE: Test might take about 5-10 min depending on your sd-card speed!
      Please be patient during this time...

Evaluating write-BW...
100000000 bytes transferred in 9.372 secs (10670081 bytes/sec)
100000000 bytes transferred in 6.579 secs (15199878 bytes/sec)
100000000 bytes transferred in 6.252 secs (15994881 bytes/sec)
100000000 bytes transferred in 6.321 secs (15820281 bytes/sec)
100000000 bytes transferred in 6.532 secs (15309246 bytes/sec)
100000000 bytes transferred in 6.516 secs (15346838 bytes/sec)
Write BandWidth: 14.0415 MBps

Evaluating read-BW...
100000000 bytes transferred in 5.168 secs (19349845 bytes/sec)
100000000 bytes transferred in 5.038 secs (19849146 bytes/sec)
100000000 bytes transferred in 4.661 secs (21454623 bytes/sec)
100000000 bytes transferred in 4.671 secs (21408691 bytes/sec)
100000000 bytes transferred in 4.694 secs (21303792 bytes/sec)
100000000 bytes transferred in 4.693 secs (21308331 bytes/sec)
Read BandWidth: 19.8165 MBps

Cleaning up all the temporary files...

Phone memory

$ ./sdCardSpeedTest.sh /data/local
NOTE: Test might take about 5-10 min depending on your sd-card speed!
      Please be patient during this time...

Evaluating write-BW...
100000000 bytes transferred in 6.876 secs (14543339 bytes/sec)
100000000 bytes transferred in 8.566 secs (11674060 bytes/sec)
100000000 bytes transferred in 8.565 secs (11675423 bytes/sec)
100000000 bytes transferred in 6.783 secs (14742739 bytes/sec)
100000000 bytes transferred in 7.617 secs (13128528 bytes/sec)
100000000 bytes transferred in 8.168 secs (12242899 bytes/sec)
Write BandWidth: 12.3989 MBps

Evaluating read-BW...
100000000 bytes transferred in 5.537 secs (18060321 bytes/sec)
100000000 bytes transferred in 5.641 secs (17727353 bytes/sec)
100000000 bytes transferred in 5.274 secs (18960940 bytes/sec)
100000000 bytes transferred in 5.275 secs (18957345 bytes/sec)
100000000 bytes transferred in 5.268 secs (18982536 bytes/sec)
100000000 bytes transferred in 5.273 secs (18964536 bytes/sec)
Read BandWidth: 17.7468 MBps

Cleaning up all the temporary files...

I have compiled these results in a tabular format for quick comparison.

Location	Write BW (MBps)	Read BW (MBps)
External sd-card	3.81	5.41
Internal sd-card	14.04	19.82
Phone Memory	12.40	17.75

If you find any issues with this tool, do drop-in a comment here!

How did I 'almost' brick my phone (and recovered from it)?

I use CM7 (nightly-74). When I heard that LG had released 0622 baseband version I couldn't resist to go back to stock ROM and try it out. :) And I did exactly that... However, somehow, during the update using the LG PCsuite, it said 'failed to communicate with phone' and asked me to remove battery, restart and plug in USB and start over again. When I tried that, after the LG boot-splash, I got this screen. :( And that's when I knew, I had screwed up my phone!

Then I went to modaco-forums to find that Paul had given a nice tutorial on how to flash your phone to the stock ROM (using nvflash). I successfully flashed the stock ROM. But little did I knew that worse was waiting when I would boot the phone. My baseband firmware was no more! Meaning my phone had become a wifi-tablet :(( Luckily, I found this thread in modaco-forums on how to flash baseband-firmware (using smartflash). Instructions were pretty simple and using this, at the end, I was able to get back my baseband to 0622 version :D (phewww!!)

Now, I just had to manually install CWM (ClockWorkrecovery Mod) version 4.0.0.5 and restore my CM7 (nightly-64) from the nandroid backups. Now I'm enjoying the nightly-74 on CM7 with the latest baseband firmware!

Manually installing clockworkmod (CWM) recovery on LG O2X

Strange as it seems, on my phone, 'ROM Manager' does not allow an upgrade to the CWM after 3.0.2.8. :( So, I wanted to install it manually. The steps I followed were from the one given by our very own Paul on modaco forums. However, I wanted to understand what exactly those 'install-clockworkmod-windows.bat' kind of scripts did. Here it is... (I used the windows batch file in order to install CWM)

# copy over the psneuter binary to your phone

> adb-windows push psneuter /data/local/psneuter

# give this binary on your phone, the executable permission> adb-windows shell chmod 4755 /data/local/psneuter

# run this exe, (psneuter exploit to gain root access)

# you wouldn't need it if your phone is already rooted(?)

> adb-windows shell /data/local/psneuter

# wait the device to come online (as the above exploit would have killed the adbd)

> adb-windows wait-for-device

# copy the CWM image over to your phone> adb-windows push clockworkmod.img /data/local/
 

# place this image over to the appropriate location?

> adb-windows shell dd if=/data/local/clockworkmod.img of=/dev/block/mmcblk0p7

Clockworkrecoverymod v3.0.2.8 bug! :(

Seems like this version does not properly restore the nandroid backups. I tried to restore using this version and the restore succeeded. However, during the bootup, (LG O2X) it used to hang on the second LG screen! The solution is to upgrade it to later version (latest verion 4.0.0.5) seems to work properly. I'll write a blog on how to manually upgrade CWM sooner...

Android adb “Unable to open sync connection!”

This happens sometimes on eclipse (or you can also experience with working on adb commandline). Unfortunately, the best known solution so far is to:

1. Unplug the USB cable.
2. Disable the USB debugging mode on the phone, and re-enable it.
3. Then re-plug the USB cable!

Courtesy: StackOverflow.

Using LG Optimus 2X under USB debugging mode on Ubuntu

If you want to develop/debug applications or even connect ddms/adb to your LG-O2X, you need to setup udev rules, in order for it to be detected by the OS. I'm assuming here that you have already installed android SDK for this purpose, if not please do so (google it!) before proceeding.

In order to do this, at first you need to open a terminal Applications->Accessories->Terminal. Then type in the following commands into your terminal. As soon as you enter the command below, you might be prompted for your password. Enter it to proceed with privileged access.

    gksudo gedit /etc/udev/rules.d/90-android.rules

In the text editor which opens, enter the following line:

BUS=="usb", SYSFS{idVendor}=="1004", OWNER="<userName>", GROUP="<groupName>"

Where: 

1. <userName> is your user name on this machine. Yes! this means that this setting only works you alone! 

2. <groupName> is the name of the group you belong to on this machine. 

3. 1004 is the vendor ID of LG (Courtesy: theandroidphone) 

4. (Google on how to get your username and groupname if you don't know!)

Save and close this file. Then type the following command on your terminal:

    gksudo service udev restart

After this is done, plug-in the USB cable of your phone (if it's already plugged in, remove and re-plug) and in your phone enable USB debugging by: Settings->Applications->Development->USB debugging.

Then type the following command to make sure your phone is getting detected:

    adb devices
You should see something like below in the terminal:

List of devices attached
XXXXXXXXXXXXXXXX    device

PS: All this information is from my PC running Ubuntu-10.10 (the Maverick Meerkat).

Installing Cyanogenmod7 (Gingerbread build) on LG Optimus 2X

Even though the guidelines to do so are described nicely in the CyanogenMod wiki, there are small things this wiki forgets to mention, which caused me a lot of pain when I followed the steps mentioned in them. This blog is an attempt to make the process of installing cyanogenmod as smooth as possible. These were the steps I followed on my O2X (LG Optimus 2X) to successfully install Cyanogenmod ROM.

Step0. Terminology:
If you are new to the world of android-hacking or new to android, in general, make sure that you are familiar the terminologies mentioned in this wiki.

Step1. Pre-requisites:

Do make sure that you satisfy all these before proceeding!

1. Make sure that you have atleast 50% (to be on safer side, 75% :D) of battery charge remaining. This is highly important! If a low battery shuts down the installation process, then there's a very high chance that you are going to brick your phone!
2.  The Recovery Mode somehow doesn't mount the internal sd-card of your phone. So, you have to make sure that you have another external sd-card plugged-in of atleast 2GB in size (on a safer side).
3. If you have data like contacts, sms, call-log and such other stuffs, now's the time to get a backup of them (onto sd-card). Titanium Backup is a nice app for this purpose. Basically, all of the data on phone will be wiped-clean during this process. So, backup all those things on your phone, which you feel is important to you.
4. You need to download/install all of these tools/files on your PC, before proceeding further: (This tutorial assumes that you are working on a PC with Windows-OS running on it)
1. Install ADB. There's a very nice tutorial on how to install this tool. I recommend you to go through this link for more details. (Please do NOT perform the step4 mentioned the above tutorial link).
2. Download busybox: Download this zip and extract its contents.
3. Download psneuter: Download this zip and extract its contents.
4. Download Superuser apk: Download this apk file onto your PC.
5. LG USB drivers (v3.2.1): Download this exe and install it to your PC.
6. It will be handy if you can extract the contents of all the zip files above into a single directory.
5. Install ROM Manager on your phone: This is a very useful tool in booting to recovery mode and then installing ROM's of your choice.
6. CyanogenMod ROM: Go to this link and download the latest nightly OR if you want to play safe, you can download the nightly numbered 53, because that's the one I downloaded and it works fine for me :). Download it to your pc and then transfer to over to your phone's sdcard. DO remember to store this zip file in the root of your external-sdcard and name it as update.zip!
7. Google Apps: Default cyanogenmod ROMs do not have any google apps installed on them, so you would have to install them by yourself. You can download the zip file from here and then transfer it to the root of your external-sdcard and let's say that you name it as google.zip.

One small thing before you proceed, as soon as you boot into recovery mode, your phone goes into an eternal vibration mode. Don't panic. It's a bug in recovery mode and it will not affect the installation process.

Step2. Rooting:

You need to root the phone prior to installing cyanogenmod. Here are the steps you need to follow for this: (In step4, the commands appearing the first indentation level are the ones you will be typing on the command prompt and the ones in the second indentation level are the ones you will type inside the shell opened by 'adb'.)

1. In your phone, enable 'USB Debugging': Settings->Applications->Development->USB Debugging.
2. Connect your phone to this PC via USB cable.
3. On your PC, open command prompt and 'cd' into the directory where you had extracted all the files from the zip files downloaded.
4. In the command prompt type the the following commands:
1. adb push busybox /data/local/
2. adb push psneuter /data/local/
3. adb push su /data/local/
4. adb shell chmod 777 /data/local/busybox
5. adb shell chmod 777 /data/local/psneuter
6. adb shell
1. /data/local/psneuter
7. adb shell
1. mount -o remount,rw -t ext3 /dev/block/mmcblk0p25 /system
2. mkdir /system/xbin
3. /data/local/busybox cp /data/local/su /system/xbin/su
4. chown 0:0 /system/xbin/su
5. chmod 6755 /system/xbin/su
6. ln -s /system/xbin/su /system/bin/su
7. exit
8. adb push Superuser.apk /system/app/Superuser.apk
5. Reboot.
6. Your phone has been rooted.

Step3. Installing Cyanogenmod:

Note that when you are in recovery mode, you should use the volume up/down buttons to navigate the options on the screen. In order to select an option, press the power button.

1. Open the 'ROM Manager' application on your phone.
2. Tap on 'Flash ClockworkMod Recovery'.
3. Select LG Optimus 2X in the menu that pops up.
4. You will get a 'Superuser Request' prompt. Select 'Remember' and then 'Allow'.
5. As soon as the flash is complete, you'll see a 'Successfully flashed ClockworkMod Recovery!' dialog box. Tap OK.
6. ClockworkMod Recovery should be installed on your phone.
7. Tap on 'Backup Current ROM' in order to backup your current ROM (which is, in most cases, the manufacturer supplied, stock ROM).
8. 'Reboot into Recovery'.
9. Select the option 'Wipe data/factory reset'.
10. Select the option 'Wipe cache partition'.
11. Select the option 'install zip from sdcard' and then select 'apply /sdcard/update.zip'.
12. Select the option 'reboot system now'. 
13. Now, your phone should boot into the Cyanogenmod ROM!

After this, if, you need to install the google-apps using google.zip:

1. Open the 'ROM Manager' and select 'Reboot into Recovery'.
2. Select the option 'install zip from sdcard' and then select 'choose zip from sdcard'.
3. Select the 'google.zip'.
4. Now, after your phone boots up, you'll be taken through series of asking you to confirm what are all the apps you want to be installed. Select the ones you need and you're done!

Lemme know how the info in this blog worked for you! Feedback on whether this content was useful to you would also help. : )

Happy modding!

Java API for Bitly webservice

I wrote a Java API for Bitly webservice (details about this webservice can be found here). It provides a easy interface to the output of the webservice, by parsing the JSON format and storing the values in the corresponding variables inside an appropriate 'BitlyResponse' object. This could be a very useful API for accessing url-shortening services from inside java apps (could be for android as well!). You can find the jar file and the relevant code at the following github repo: git@github.com:teju85/BitlyAPI.git

PS: There's no restriction on the using this library, provided you acknowledge the use of this API in your application. :)

How to compose an 'attrs.xml' in android?

There are a lot of blogs which describe how to create custom attributes [3-5]. But I couldn't find anyone which describes the syntax and possible xml attributes for each of the elements inside it. Also, there aren't any documentations available for this as well!

In order to figure out this syntax, I had dig into some internal android code! I know that android is open-source. I like open-source and it's cool. But one shouldn't have to dig into the code in order to understand this simple information, which could have been documented.

Thus this blog is an attempt from my side to document this feature, so as to keep others from wasting their time in doing the same!

declare-styleable

List of possible xml-attributes for this element:

1. name: name of this styleable.
2. parent: name of the styleable from which to inherit the attributes.

List of possible children:

1. attr: the attribute which needs to be defined inside this styleable.

attr

This element can either be found as a tag outside the 'declare-styleable' tag or as an child inside it. List of possible xml-attributes for this element:

1. name: name of this attribute.
2. format: data-type represented by this attribute. (This is optional)

List of possible children:

1. enum: If the current 'attr' is of type 'enum', then you have to define possible enumerations for this attribute.
2. flag: If the current 'attr' is of type 'flag', then you have to declare this.

enum

List of possible xml-attributes for this element:

1. name: name of the enum element.
2. value: the value to be used for this element.

flag

I'm still unable to figure out the syntax for this element. Whenever I'll find out, I'll update this section. So, please do check-back here for more info on this!

format

One small catch here! I just said that this is an optional attribute to 'attr' element. However, from the code [1] it seems that an 'attr' with not 'format' will be silently ignored! Hence, I would recommend putting one of the values below for this attribute. Possible values for 'format' attribute of 'attr' are: [2]

• reference
• string
• color
• dimension
• boolean
• integer
• float
• fraction
• enum
• flag

That said, an example should clarify much of the stuffs here. Given below is an example 'attrs.xml' which contains all the above elements/attributes. Go through this carefully in order to understand the syntax.

An example 'attrs.xml':

<resources>
    <attr name="global1" format="float"/>
    <declare-styleable name="parent-attr">
        <attr name="attr1" format="integer" />
        <attr name="global1" />
    </declare-styleable>
    <declare-styleable name="myattr" parent="parent-attr">
        <attr name="attr2" format="integer" />
        <attr name="attr3" format="enum">
            <enum name="name1" value="value1" />
            <enum name="name2" value="value2" />
        </attr>
    </declare-styleable>
    <declare-styleable>
        <attr name="global1" />
        <attr name="attr4" format="boolean"/>
    </declare-styleable>
</resources>

NOTE:

1. All the 'attr' elements in the current xml file will be parsed into a single 'Map'. So, you have to make sure that all 'attr' elements have unique names! [1]
2. However, if there is an 'attr' element which needs to be shared between 2 styleables, then make it global. (But make sure that you specify a 'format' for this!) Now inside the 'declare-styleable's where you want to define this 'attr', just put this without the 'format'. There is an example of this in the sample xml above. [1]

REFERENCES:

[1] http://code.google.com/p/idea-android/source/browse/trunk/src/org/jetbrains/android/dom/attrs/AttributeDefinitions.java?r=96

[2] http://code.google.com/p/idea-android/source/browse/trunk/src/org/jetbrains/android/dom/attrs/AttributeFormat.java?r=96
[3] http://developer.android.com/resources/samples/ApiDemos/res/values/attrs.html
[4] http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/LabelView.html
[5] http://blog.pocketjourney.com/2008/05/02/android-tutorial-42-passing-custom-variables-via-xml-resource-files/

PS: Please do leave comments if you find anything incorrect. I'll update the blog accordingly.

Proguard.cfg missing in eclipse?

This happened to me after I updated my eclipse today. Basically, whenever I was trying to create a new project, I used to get this error message. The reason for this error is due to mismatch between the versions of your ADT, sdk-tools and eclipse. The best thing to do is to upgrade all of them to their latest versions.

Upgrading ADT: From inside eclipse, Help -> Check for Updates and then follow the instructions.

Upgrading sdk-tools: From inside eclipse, Window -> Android SDK and AVD manager and then follow the instructions.

After you are done, just restart the eclipse and you'll be back on track!

Small class to quickly print out application information in HTML

Wrote a class, which queries the package manager in order to fetch the package name, version code/name and permissions for a given app. There's also a method which returns a html formatted string which could be used to display your app's info (probably in a TextView or an AlertDialog). This will help avoid creating a separate 'about' HTML for your app. Go through this link for more information on this class. (The source file has been released under APACHE LICENSE2)

Setting up LG-Optimus One for development

I have been writing android-apps for over more than 8 months now. Finally, I got hold of my first android smart-phone, LG-Optimus One (Model name P500). The following were the steps I had to perform in order to get this phone ready for Android development.

Installing USB driver:

By default, this phone will not be detected over USB, as windows (Win7 32b) failed to find the USB driver for this device. Google search suggested that P500 USB driver needs to be manually installed. To do that, just go to the following link: http://www.lgforum.com/resources/ and select the 'LGAndroidDriver_Ver_1.0_All.exe' executable (about 9.4MB). Then run this exe in order to install the USB driver. Wallah! You're done!

Enabling USB debugging:

Again, by default, USB debugging will be disabled on this phone. (Makes perfect sense as this feature is for development only) In order to enable just select the Settings -> Applications -> Development -> USB debugging check-box. Now connect the USB cable. After this, open a command-prompt and then type adb devices. You'll see something like this:

> adb devices

List of devices attached
******************      device

 You're done! Now, you should be able to run an application (assuming android:debuggable is set true in the app's AndroidManifest.xml) and see the log messages through 'ddms'.

Happy coding!

traceview fails to find the trace file (on windows)

You have the trace file 'my-trace.trace' present in the current working directory. However, when you type traceview my-trace, you would get the error message: "trace file 'my-trace' not found". Even if you append the trace file with the '.trace' extension, you would get the same error message.

Somehow, the traceview cannot recognize relative paths. So, the solution is to pass the absolute path of the trace file as input to the traceview.

EG: traceview C:\path\to\file\my-trace

(PS: It's been assumed here that the android-tools folder is in your PATH env-variable.)

TouchUtils.clickView too slow!?

Here's the scenario...

• You have written an android test-suite for your application.
• Your test cases use 'TouchUtils.clickView' class by android, in order to simulate clicking the buttons on your view.
• However, time between each click is slow to the extent that it has become the bottleneck in your test-suite! 

In the implementation of TouchUtils.clickView, there's a sleep of 1000ms (1sec) after every call made to this function. This is the reason for the delay you've been seeing.

 So, I went ahead and copied the code for 'clickView' and created my own class for providing users with programmable delays. This would help the verification guys to fine tune the delays between each clicks. Hence, trying to keep the runtime of the test-suite under control.

 This class 'MyTouchUtils' can be found here. Just save this file to your project and 'import' this class into your test files. Then, if you want to simulate a click event with 200ms of delay after the click, just do the following:MyTouchUtils.myClickView(this, view, 200);

 Of course there's a trade-off involved between the time given for your program to settle down, digest your click event and produce the results; and the total runtime of your test-suite. So, you have to make the decision accordingly.

Happy Coding!

Android Instrumentation Testing

This article will talk about a strange "permission denial" issue which occurs when  trying to run android instrumentation on eclipse. Of course it'll also disclose the solution to it :).

So, what's the problem?

Whenever you try to run the android test-suite for your application, you see an error message like the following in the 'Console' area of your eclipse IDE.
"Test run failed: Permission Denial: starting instrumentation ComponentInfo{<testPackage>/android.test.InstrumentationTestRunner} from pid=123, uid=123 not allowed because package <testPackage> does not have a signature matching the target <targetPackage>"

Reason?

The error message is pretty self-descriptive. As you might have figured out, it's basically due to a signature mismatch between the <targetPackage> and <testPackage>. In simple words, eclipse is using different certificates for signing up your application and for it's test-suite.

Solution?

Generally, when you are running test-cases on your application, you would want to use debug certificates. Eclipse, by default uses debug certificates. So, best way to solve this is to start from scratch. For that, just do the following. In the 'Package Explorer' right click on your target application -> Source -> Clean up. Repeat the same thing for your test application as well. After this, rebuild both of them. Then you'll be right back on the track.

Happy coding!