Develop Reference

Yet Another 'The project was not built since its build path is incomplete'

I have an Android project that I've been happily building for weeks in Eclipse Indigo. I have not changed any settings, libraries, or workspace components, or added or removed any files. A few hours ago I was doing a "Run as" to run my app on a phone and Eclipse did a hard hang. I couldn't even kill it in Task Manager so I rebooted my PC.
Now when I try to build my app I get
"The project was not built since its build path is incomplete. Cannot find the class file for java.lang.Object. Fix the build path then try building this project"
I deleted gen and did a clean and build with the same result. In the project Properties for the build path, in the Libraries tab it shows
Android Dependencies
Android Private Libraries
Unable to get system library for the project.
Any idea what's going on? This Eclipse "build path is incomplete" error is very common but when I search Stack Overflow and Google, most of the cases seem to be related to importing new projects, moving workspaces, changing libraries or other things I didn't do.
Thanks in advance!

I fixed my problem.
I did a File>Switch Workspace and switched to another workspace that had a different project in it. Then I switched back to my original workspace and everything was fine.
So we can add this to the very long list of folk-remedies, nostrums, old-wives-tales, superstitions and other bits of software lore that accompany the various weird bugs that afflict Eclipse. I sure hope Android Studio turns out to be better than this!

This worked for me:
Open project properties > Java Build Path > Libraries.
Select "Unable to get system library..." > Remove > OK.
Open Libraries again > Add Library > "Android Classpath Container" > Next > Finish > OK.

The following worked for me, so I thought I would share.
Restarted Eclipse and ran into the same problem.
Did the following to get my project to build again.
Right click on project inside Package Explorer and Select properties.
Go to Java Build Path.
Click on Libraries TAB
Remove the line that says "Unable to get system library for the project"
select ok.
Then right click on project, and select "Android Tools" -> "Fix Project Properties."
Hope this helps.... eclipse can be a real PITA sometimes.
BTW I "watched" for any changes after the delete and fix, and it looks like
Is removed from .classpath, and then the "Fix Project Properties" adds the line right back.
Clean + Build works after that.

The resolution was to force a resave of the selected projects (and their .classpath files):
Open the project properties
Select Java Build Path > Libraries
Add a new, arbitrary library (to be deleted later) > OK
Wait for the workspace to refresh (or force a refresh of the project)
The error(s) will go away
Remove the dummy library

Try Project-->Clean. Also make sure "Build Automatically" is checked

"R cannot be resolved" may have wrong build path or libraries import

I know this question has been many times but trust me I have checked all. Most of the question suggests to remove import android.R , remove any error in the xml file, checking name of the files (no capital letters) then rebuild and clean the project or restart eclipse. I have tried all but none solved the problem.
The problem occured when i cleaned all the projects. Now all the projects are showing that error. Since all the project were running perfectly before i cleaned projects, there is no possibility that all of the sudden the layouts or the file names of all the projects have error in them.
Also there is no file in gen folder. As far as i can understand there is something wrong with the build path or preferences can anyne point me in a correct direction? !

Make sure you installed the Android build tool form sdk manager
project right click properties-> Java BuildPath select Library and add android-support.jar the follow these step.
Go to Project->Properties->Java Build Path than select Order and export tab. Set android-support .jar library checked and up it into top of the list. And clean and rebuild..It works for most of the cases

Check the answer here and the thread here. Check if your layouts contain any errors (this has to be done manually or automatically only with Android Studio). Search for incorrectly closed tags like <string> - </string>.
EDIT (taken from this thread):
Cleaning a project removes all auto-generated files. Building the
project it should automatically create them. When you Clean a project,
there's an option to start a build immediately after clean up.
Here's a few things you can try (did the same procedure after manually
deleting the "gen" directory.
After you have deleted the gen directory, go to Project > Clean ...
You should have errors indicating that R cannot be resolved to a variable. Right click on your project from the Package Explorer and
select Build Project. Be sure Build Automatically option is turned off
(uncheck in Project > Build Automatically).
Errors regarding R should have now disappeared. Now, perform a Project Clean once again. All errors should be gone.

"Conversion to Dalvik format failed with error 1" after update to ADT 14

After updating to the latest developer tools, ADT 14, my Android project that includes library projects will no longer run producing the error:
Dx UNEXPECTED TOP-LEVEL EXCEPTION: ... already added: ...
...
Conversion to Dalvik format failed with error 1
The other threads describing this issue with solutions that include removing and re-adding the projects do not work.

This problem is listed as a known issue of ADT 14. Here's the quote from the Android Tools Project Site:
Project not building with error
[2011-10-20 23:32:04 - MyApp] Dx UNEXPECTED TOP-LEVEL EXCEPTION:<class>: already added: <class>
This is due to a failure to remove previous library source folders from the
main project. Incidentally, the fragility around those linked source
folders is one of the reason we are moving away from this mechanism
(see more info at
http://tools.android.com/recent/buildchangesinrevision14). The
solution is to remove those <libraryname>_src source folders from
your projects. Just right click them and choose Build Path > Remove
from Build Path. You should also be prompted to remove the linked
folder which you should do. If you're not prompted, remove it
manually. You can see some screenshot of the problem in this great
post:
http://android.foxykeep.com/dev/fix-the-conversion-to-dalvik-format-failed-with-error-1-with-adt-14
Solution:
As it says, the solution is to remove the <libraryname>_src source folders from your projects. You can do this by right clicking them and choose "Build Path -> Remove from Build Path" or in your project properties (Java Build Path -> Source tab).

I also ran into this problem, but none of the above fixed it:
Tried removing/re-adding libraries with clean builds along the way
Tried deleting and re-importing projects
No dice. Still the "Conversion to Dalvik format failed with error 1" was staring me in the face every time I tried to export to an apk.
I could tell the problem was related to ProGuard, because when I commented out this line in my project.properties file, everything worked fine:
proguard.config=proguard.cfg
However, I wasn't able to solve the problem until I found this post by David M Young. Apparently, ADK/ADT 14 shipped with an incorrect version of ProGuard (oops!). I downloaded ProGuard version 4.6. Replaced the android-sdk\android-sdk\tools\proguard\lib directory contents with proguard4.6.zip\proguard4.6\lib (3 *.jar files), restarted Eclipse and export to apk worked again!

To solve you should:
Right click on your project>Properties>Java Build Path and remove all libs but the one Android I.J (depending on your version)
Project>Clean
Add back the libs you've removed
If the problem comes back another times it's useful to put the libs outside your project and import them as "External JARs"

Hello thought I'd throw my two cents in here. as I did do that,
"_src -> Remove from path"
Then I cleaned it and rebuilt and I could get it to run in debug mode on my phone just fine. I could also export it; but only if I disabled proguard. of course I couldn't leave it like that with my code open for all to see. so it was quite madding. but I Finally found a cure, oddly enough they had the same problem (and fix) with r12 as they do with this one.
it's in: [Android SDK Installation Directory]\tools\proguard\bin\proguard.bat
Change
call %java_exe% -jar "%PROGUARD_HOME%"\lib\proguard.jar %*
to
call %java_exe% -jar "%PROGUARD_HOME%"\lib\proguard.jar %1 %2 %3 %4 %5 %6 %7 %8 %9
I tried tons of other stuff but this is what did it for me.

This is a known problem with the android sdk. Check out this blogpost for a fix.

I used a library for my project and had the same error - it was solved by removing library and src-folder, cleaning and adding it back and cleaned again.
Remove
Project properties -> Android: Remove libs, 'Apply'
Remove included library src-folder
better clean,
Add again
Project properties -> Android: Add libs again, 'Apply'
Clean project

Just had this problem come back again (fixed first time by removing the _src items as mentioned in other answers) - this time there were no _src files to remove. The error was relating the android-support-v4.jar which was included as part of a linked library project as well as part of the main project itself.
Error Dx UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.IllegalArgumentException: already added: Landroid/support/v4/content/ModernAsyncTask$WorkerRunnable;
Problem went away after removing the android-support-v4.jar file from the build path for the main project. Don't think I came across this as possible cause to the errors.

Go to Project » Properties » Java Build Path » Libraries and remove all except the "Android X.Y" (in my case Android 1.5). click OK. Go to Project » Clean » Clean projects selected below » select your project and click OK. That should work.
It is also possible that you have a JAR file located somewhere in your project folders (I had copied the Admob JAR file into my src folder) and THEN added it as a Java Path Library. It does not show up under the Package Explorer, so you don't notice it, but it does get counted twice, causing the dreaded Dalvik error 1.
Another possible reason could be package name conflicts. Suppose you have a package com.abc.xyz and a class named A.java inside this package, and another library project (which is added to the dependency of this project) which contains the same com.abc.xyz.A.java, then you will be getting the exact same error. This means, you have multiple references to the same file A.java and can't properly build it.

I had the same issue, I'm using the ADT 20.0.3.
Steps I followed to resolve this.
Remove all the jar in project/lib folder and reference them as external jars.
Check android dependencies/reference libraries in project for duplicates,

I've dealt with this problem when using Sherlock ActionBar library in my project. You could do the following step, it's work for me.
Right click to your project, select properties.
A dialog will show up, select 'Java build path' on the left menu.
Remove 'Android dependencies' and 'Android private libraries' on the right panel then click OK
Clean your project (select menu Project --> Clean)
Right click your project, select Android Tools -> Fix project properties
Clean project once again.
Restart your computer
Open eclipse and Export apk
Hope that will help you.

In eclipse, unable to reference an android library project in another android project

As I was writing up this question I managed to solve it so repeat it here for the benefit of others. Here is the initial problem:
I have created a very simple library project which I want to reference in another project. I have done this previously with no problems so not really sure why it is not working this time. I have:
Flagged the library project via project properties. The default.properties file has this set : android.library=true
In my other project added reference to my library project via project properties. The default.properties file has the reference added as expected ie android.library.reference.1=K:/android_test_ws/applicationRegistrar
The green tick against the referenced library project starts off green and then changes to a red cross.
This implies that there must be something wrong / missing from the library project but I don't know what. My library project on this occasion is MUCH simpler than the previous one I created.

OK Here is the solution which I found when I was looking for the default.properies file of the referencing project (not the library) in my file system. Although the referencing project was in the same eclipse workspace as the library project, the actual files were somewhere else in the file system ie they were'nt in the same parent folder of the library project. As soon as I placed the referencing project in the same physical folder as the library project it all went fine.
I guess that this must be something to do with android using ant underneath the covers.
Edit: The project name needs match the folder name on the file system. What you are seeing in the Project Properties->Android->Library Reference is a relative file system path.

Make Sure both the projects are present in same work space.
To Do it, while importing the projects make sure "copy project into work space" check box is checked.

the same problem will occur if your library project is in different partition from your current workspace. I have the same problem just now. My git source is in C: and I just move my workspace to D: and everything start to collapse.

Simplest way to get the library paths paths correct is to use the GUI from Eclipse to add the library as shown in the following screenshot and let Eclipse take care of putting the correct relative paths in project.properties. Its a common setup to have your library projects hosted at directories vastly different than your main projects that uses the library. This method will work if the "libary project" and the project using it are in the same eclipse "workspace" (they "need not" be in same parent folder):

Please ensure that the library project is marked as "Is Library" - right click on the library project - properties - Android - mark the "Is Library" checkbox - in project.properties of the library project you should have a new entry:"android.library=true. Now add it into the project you want as described in the post below.(the post with image integrated - from Nilesh Pawar).

This bug is referenced several times here 27199, 35786, 36460 & 38052
Maybe by voting for them, it will be fixed one day...

Yet another observation on the same issue.
For me the two projects where on the same parent folder, and were both local inside the workspace. Even then the issue was still happening.
The I edited the "project.properties" file and put the absolute path(with forward slashes '/' for seperator) of the library project. Saved and closed it. Then went to the project properties dialog, removed the library(which was still showing the cross icon but with abs path) and added it back as usual.
Surprisingly the issue is resolved, and the project compiles and runs.
This is really strange and must be a bug with the ADT.
I am using ADT version 20.0.2

when developer referencing the facebook or any other library project then first of all clean the project from eclipse->project->clean project.
that want allow the error of red cross in referencing screen.

For me, I just restart the eclipse and the added library works fine.
I mean first time it showing red marks after adding the library project.
Though eclipse main project and library project are in same workspace folder and no resources files are in outside of the project folder.
So, you can try with to restart your eclipse. Happy coding....

Workaround for me was to
Create a new workspace
Import Library Project in that workspace
Import The desired project in that workspace
Having both project and library project the same target Android OS version
Reference library project in my project
solved my problem

i had the same problem there when i try to change my workspace so this my solution:
import and copy all project data including library project into workspace
delete the old project reference by Right-click on the project-->Properties-->Android-->Library, and select corrupted library(so that waht i call it) and choose Remove
clean project first (to refresh ur project properties)
go to library project Properties-->Android-->Library and check the is library if it does'nt click Apply then OK
if the library project is library is already checked, first Unchecked it then Clean the library project after that do the Step 4 again
go to project that u want the library are in then Right-click on the project-->Properties-->Android-->Library, Add then choose the library project (it should be there) and click Apply then OK
if still doesn't appear clean the project once more time and that should do

Just restart your eclipse. It's solve my problem

When you have a look at the reference-path before and after, it comes from i.e. "C:/workspace/mylib" and goes to "../../mylib" when copied to the correct location, quite interesting.

FYI,
What worked for me was to delete the 'library' projects (the actual projects) from my workspace (without deleting the files), and then re-importing them using the wizard (import existing android project from source code).

Thanks for posting the question.
I had exactly the same problem while integrating Facebook with my Android application. I fixed the issue by moving my development project to the same Windows drive in which library project was located. Somehow Eclipse is unable to read the library project's location properly from default.properties file if it is in a different drive.

Similar to Sufi Khan's post I also solved this issue with a reboot. My case differed in that when I first accessed Properties->Android and added the library I got a lovely green checkmark. When I closed the dialog Eclipse was still showing class-not-found type errors. When I checked the properties again I saw the red X. But Mr. Kahn's solution (delete the bad lib, restart Eclipse, add the lib again) worked fine.
I'm using the 0702 version of the ADT bundle (starts with "cluster", rhymes with "duck").

I followed the accepted answer but also had to make sure my "project.properties" file was readable.
If the file is readonly (checked into source control) eclipse will not edit it. Adding the library reference will succeed, but the change won't be persisted after hitting OK.
If closing the preferences window and reopening in again removes the library you just added, this may be your solution.

In case your library project still doesn't show up try adding library flag in your library project properties
Add android.library=true
project.properties
# This file is automatically generated by Android Tools.
# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
#
# This file must be checked in Version Control Systems.
#
# To customize properties used by the Ant build system edit
# "ant.properties", and override values to adapt the script to your
# project structure.
#
# To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):
#proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt
# Project target.
target=android-17
android.library=true

Missing AndroidManifest.xml when importing an old Android project into Eclipse

I have an Android project developed on Eclipse (GNU/Linux) that I last touched half a year ago. I am trying to import the project into Eclipse 3.6 on Windows (with ADT installed) installed using File -> Import Project in Eclipse. When the project is imported, I see the following error twice on the console:
[2010-12-10 02:17:12 -
com.android.ide.eclipse.adt.internal.project.AndroidManifestHelper]
Unable to read C:\Program
Files\Android\android-sdk-windows\AndroidManifest.xml:
java.io.FileNotFoundException:
C:\Program
Files\Android\android-sdk-windows\AndroidManifest.xml
(The system cannot find the file
specified)
Why is Eclipse looking for AndroidManifest.xml on the Android SDK path? The file actually seems to be in the project's directory. How do I fix this problem and get the project to compile?

A simple solution is to either reimport the AndroidManifest.xml file or make a change to the file and save it. This worked for me.

If you see an error about AndroidManifest.xml, or some problems
related to an Android zip file, right click on the project and select
Android Tools > Fix Project Properties. (The project is looking in the
wrong location for the library file, this will fix it for you.)
from: http://developer.android.com/resources/tutorials/notepad/notepad-ex1.html

The way you are importing the Android project into Eclipse is wrong. The Correct way of doing is File -> New Android Project. In the Contents Tab in "New Android Project", select "Create project from existing source" and choose the Build Target. That should fix your problem.

It appears that this error is produced because Eclipse thinks the default location for new Android projects is the Android SDK path. Even if the project location is changed, the error fails to be resolved, so the trick is to change the project location before Eclipse is aware of the condition generating the error.
To circumvent this quirk I imported the old project with the following steps:
File -> New -> Android Project
Un-check 'Use default location' and browse to project root directory.
Click 'Create project from existing source'
It's important to do step (2) before (3) otherwise the error persists and prevents running the project.

I had the same problem, all of the above did not work. I cleaned the project and it worked.

Instead of using File ---> New Android Project --> "Create project from existing sources", which will result in the error your are seeing, choose "Create project from existing sample" and choose it from the drop down. This will work.
Experienced JAVA developers tend to go with the first option which is normally there and works for classic Eclipse projects. But this is not your typical project and I bet the Google developers put this special case in the wizard to accommodate the differences.

I had the same problem. I was trying to compile the JakeWharton view page sample, so I checked out the GIT in a directory in a different folder then the workspace which caused the problem.
Eclipse was maintaining 2 folders:
1. A new workspace folder was made under the workspace directory, which eclipse checks for libraries and others source code including the AndroidManifest.xml file
2. The existing folder which was not under the Root workspace
To fix the problem after importing I had to manually move the files in the new workspace folder created by eclipse.

I met this problem when using Facebook SDK, now I solve it by doing this:
Close the project;
Copy "AndroidManifest.xml" file to the project's root path;
Open the project and refresh it, it's Done!

this worked for me by the way:
I changed the project name to the exact name of the project that I am importing.

Eclipse seems somewhat fragile in its naming conventions. One of the causes for this error is a difference between the project name and the folder name in the workspace. I imported a zip file for a project named "HelloDialogs" into a workspace folder named "HelloDialog". This caused the "AndroidManifest.xml file missing" error. Once I renamed the folder correctly, everything worked fine.

Because of the multiple different answers here, I thouhgt I'd add yet another one that worked for me, as I had exactly the same issue when first working with Phonegap android dev tools.
So I found (as mentioned by Gintautas in comments to the accepted answer), that I had to create a new project using the phonegap 'create' script, then when importing the project into eclipse. the only way to get this to work successfully was if the project was originally created in some temp folder somewhere other than the place I actually want to work with it.
So I created a project in windows like this in a cmd window...
c:\phonegap\phonegap-2.6.0\lib\android\bin>create.bat c:\temp\android_boilerplates\test app.test test
Then I imported the project in eclipse like this...
File > New > Project
Within the new project wizard select: "Android Project from Existing Code"
Click "Next"
Now navigate to the temp location of your project and set that to the root directory, check the project you want and check "Copy projects into workspace" as the example below...
Click "Finish"
And that's it, Eclipse should copy all your project files into your workspace and there shouldn't be any errors in your project (fingers crossed).
Your project should look something like this...
Hope that helps, it took me an age to work out why Eclipse didn't like creating a new project from existing code when the new project was being setup in the same place as the existing code. This isn't a problem for other languages I've used, so it was a little weird, but understandable as Eclipse (I'm guessing) seems to want to overwrite certain files.

Eclipse randomly decided to make another folder instead of the one that i had specified, but doesnt have any resources or data or layout etc in it..
it has some conflicts i guess..
anyway, a noob approach to this was, copying the original file to some other location(i put it to desktop)..
now create new project-create existing project, select this one from desktop, n VOILA.. its all fine.. :D

I am a little late to this game but I caused this same problem by generating the initial application into the exact location I was going to work on it. That is to say I put it directly into my current workspace. I then did File, Import, Existing Android Code Into Workspace. The import process blanked out my android.xml file.
I tried above solutions and had no joy. I then generated the initial application into a temp directory and imported from there. This worked for me.

The only way to import a project into eclipse workspace is to create an empty project and then drag and drop all the folders and files into this project. Why is this so is beyond me.
The answer from Raunak is wrong.

I found a .classpath file in the root directory of my Android project. I opened it and updated the file paths in it, and it seemed to fix the problem for me.

I had the problem when I tried to update an old project with recent code from the SVN. I had the Manifest.xml exported to my local file system as backup and deleted it. I've then reverted my complete project to the most recent version from the SVN and then it worked :)

This is what I had to do to get this to work. Fortunately I had backups of earlier "project".
1) Import the project as usual.
2) If the errors with empty xml etc. comes up, close the project.
3) Go to the original project if you have backup.
4) Copy all of the projects root files and directories and paste it over where Eclipse expects the projects root directories and files to be.
5) Open the project and refresh. Make "Clean" if necessary and you're done!
Always make backups because Eclipse f--kups! I learned this the hard way when suddenly my Android project refused to work because of empty manifest-file.

Sometimes if you automatically fix imports in MainActivity IDE imports android.R class instead of one that will be generated for the project. Remove the import and recompile.

when importing project from another workspace add existing project in workspace. and tick to the copy projects in workspace.then check the api level and supporting library from project.properties files.then rebuilt project and clean it.. it is works for me.

2017 Solution: Much Easier and tested solution is to remove your application folder from elipse project only then Import it again and the problem will be fixed immediately!