No generated R.java file in my project [duplicate]

Question

I am doing the Notepad tutorial, exercise 2. I started by creating a new Android project and chose Create from source to import the downloaded source files for the excercise.

But now I get many errors in Eclipse, and the problem is that there is no generated R.java class. How can I solve this? The folder gen/ is empty.

---

I have errors on Notepadv2.java and in res/layout/note_edit.xml and both seems to be related to the fact that the generated R.java is missing.

Here is my import statements in Notepadv2.java:

import android.R;
import android.app.ListActivity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter; 

They are created by the Eclipse command Ctrl+Shift+O.

Wonderment

For those who still experience some problem with eclipse not being able to update/generate R.java. A possible solution is by creating a dummy xml and just delete that xml. In my case this is the solution – Stuck

Literally was trying to find the answer to this all day...For both appcombat and your project. Goto properties > Android and change the Project Built Target to API level 21. – Turnbuckle

Answer 1

Go to Project and hit Clean. This should, among others, regenerate your R.java file.

Also get rid of any import android.R.* statements and then do the clean up I mentioned.

Apparently Jonas problem was related to incorrect target build settings. His target build was set to Android 2.1 (SDK v7) where his layout XML used Android 2.2 (SDK v8) elements (layout parameter match_parent), due to this there was no way for Eclipse to correctly generate the R.java file which caused all the problems.

Angulo

@Jonas: Please post up your imports. – Angulo

@Jonas: exactly. The import section of your main application. – Angulo

When I change build target from Android 2.1 to Android 2.2 the R.java is generated. But when I change back to Android 2.1 and after I do Project>Clean then the R.java is deleted again. – Wonderment

@Jonas: Don't change the target build. Have you tried what I've mentioned? – Angulo

Yes, Project > Clean doesn't help me. After that I get two errors in the Problems view. See my comment to WarrenFaith – Wonderment

after wading through legions of google groups mess trying to find this solution... what'd you know, it was on SO the whole time. – Tijuana

why getting rid of the import solves the issue? That doesn't make sense to me? – Lactobacillus

@Saher Because having the R file of another package in your class will definitely screw up everything. – Angulo

Answer 2

After one whole day trying to find why R file was not generated, I found that after install Android SDK Tools r22 a new option in Tools was available: Android SDK Build Tools.

After installing it R file was generated again.

Hazaki

I am looking for this new option where can I find it? – Oxbridge

Right Click on project > Android Tools > Run Lint : Common Errors – Skylight

Finally i solve this problem updating the Android SDK Tools and restarting eclipse, very thanks – Rocha

Thank you! Why do they always have to break things??? – Valdes

Yep, same here. Another thanks. I thought that I had already gone through that process, but it must have gotten interrupted in between when I was closing eclipse during the download and it never finished. – Batish

+1 this works, but make sure there is no other error in the project – Kiele

Answer 3

now you have imported android.R instead of your own R... Try to take a look on your "problems" view if you have errors in one of your xml files... get rid of the import android.R and comment out all usages of R.*

Cleaning should help when your project has no other errors, so check your xml files or file naming in your res folders

Alithia

When I remove import android.R I have two errors in the Problems view. They are R cannot be resolved to a variable in Notepadv2.java and error: Error: String types not allowed (at 'layout_height' with value 'match_parent') in note_edit.xml – Wonderment

Well if your target build is 2.1 then match_parent won't be available since it was added in Android 2.2. – Angulo

@Octavian: Ah, so the XML failed to parse, so no R.java is generated. Now when I change build target to Android 2.2 it seem to work. You could add that to your answer. – Wonderment

Answer 4

Probably u might be using a incorrect SDK version. Right click on your project. Select Properties-->Android. Note that 2.2 is the latest SDK. Check it and see if it gets compiled...

Edit

Also Do a clean after that

Fascist

In Properties > Android I can only choose a Build target and it is Android 2.1 which I want. There is also an empty Library section in the same dialog. – Wonderment

Yes in build target you should have selected 2.2 and yes you were indeed using the incorrect SDK version :) – Fascist

Answer 5

I Had a similar problem

Best way to Identify this problem is to identify Lint warnings:: *Right Click on project > Android Tools > Run Lint : Common Errors*

• That helps us to show some errors through which we can fix things which make R.java regenerated once again
• By following above steps i identified that i had added some image files that i have not used -> I removed them -> That fixed the problem !

Finally Clean the project !

Linwoodlinz

Answer 6

I colleague of mine has this problem - a restart of eclipse fixed it.

Douala

Answer 7

Update Android SDK Tools in Android SDK Manager for revision 22.0.1. It worked for me.

Aromaticity

Answer 8

1. Remove the 'import R.java' line from your code. Its done by Eclipse in order to solve the problem.
2. Go to "note_edit.xml" file. Wherever you find "match_parent" as an attribute value, replace it with either "fill_parent" or "wrap_content".
3. Do a clean build. R.java will be generated automatically.

If you got this problem, it means "match_parent" property is not supported in your content. Instead, "fill_parent" is used.

"fill_parent: The view should be as big as its parent (minus padding). This constant is deprecated starting from API Level 8 and is replaced by match_parent. "

Buckingham

Answer 9

Do you have installed the android plugin ?

Your project must be of the android type.

Vandavandal

This was close to the problem I was having--I think somehow I was missing something in the buildSpec section of my .project file. Not sure how it got that way, or the correct way to fix it, but I basically copy/pasted from a working project and got R.java building again. – Mitra

Answer 10

This is actually a bug in the tutorials code. I was having the same issue and I finally realized the issue was in the "note_edit.xml" file.

Some of the layout_heigh/width attributes were set to "match_parent" which is not a valid value, they're supposed to be set to "fill_parent".

This was throwing a bug, that was causing the generation of the R.java file to fail. So, if you're having this issue, or a similar one, check all of your xml files and make sure that none of them have any errors.

Spheroidal

Answer 11

I just had a problem where a previously working project stopped working with everything that referenced R being posted as errors because R.java was not being generated.

** * CHECK THE CONSOLE VIEW TOO **

I had (using finder) made a backup of the main icon (not even used) so one of the res folders (hdpi) had

icon.png copy of icon.png

Console indicated that "copy of icon.png" was not a valid file name. No errors were flagged anywhere else - no red X in the res folders....

but replacing the spaces with "_" and it is all back to normal....

Mccrory

Answer 12

I've also experienced such issues as R.java being missing, and also eclipse complaining there are errors in my code (displaying red X icon against class files) when there were no errors.

The only method I've found for solving this is to clean the project by selecting Project > Clean

This seems to solve the issue for myself, running Eclipse 3.5.2

Oriana

Answer 13

I have faced this issue many times. The root problem being

1. The target sdk version is not selected in the project settings

or

1. The file default.properties (next to manifest.xml) is either missing or min sdk level not set.

Check those two and do a clean build as suggested in earlier options it should work fine.

Check for errors in "Problems" or "Console" tab.

Lastly : Do you have / eclipse has write permissions to the project folder? (also less probable one is disk space)

Pederson

The project target is set, but I don't know about "min sdk level". Where can I see if it is set? In default.properties I only have target=android-7 – Wonderment

@Jonas: this means that the target build is set to Android 2.1. – Angulo

There is also an attribute in manifest <uses-sdk android:minSdkVersion="8" />. Did you see any kind of "errors" in the problems tab or Console? – Pederson

Yes, see my comment to WarrenFaith – Wonderment

Answer 14

yeah i have the same problem.i fixed it by selecting Project from the tool bar clean the project also reset the build automatic option some times needed to change the name of xml file match format [a-z][0-9] capital letters must be changed

Infuse

I don't know if it's a new feature, but my layout files have an underscore in their name and everything works fine. – Junie

Answer 15

It seems that when you change to the latest SDK (2.2) building no longer generates an R.java file. Or at least not in the way we're used to. To solve this delete the package underneath the gen folder and clean without building. This solves the issue for me.

Olds

Answer 16

I've got that problem because of some internall error in Android plugin. When I've tried to open some layout xml, I've got error:

The project target (Android 2.2) was not properly loaded.

Fortunatelly in my case restarting Eclipse and cleaning the project helped.

Aurelia

Answer 17

This could also be the problem of an incorrect xml layout file for example. If your xml files are not valid (containing errors) the R file will not re-generate after a clean-up. If you fix this, the R file will be generated automatically again.

Chunchung

Answer 18

According to my experince i can summarize :

1.The problem is mainly refering to syntax issues that can be occured on xml files.

2.You might copy the AndroidManifest.xml accidently to subfolders .

1.One file is an extension undefined .

After checking all of these Go to Project->Clean or just remove the /bin and /gen folders.

Mete

Answer 19

Just Restart the Eclipse will solve this Issue as the workspace will be freshly Build ! go to

File -> Restart

Its the easiest way to avoid frustration by going it into Build,properties,blah blah.....

Styliform

If this cannot solve this issue then other answers can be considered ! – Styliform

Answer 20

Here's another one: I was just about to cry, but managed to get my beloved R.java back:

I hadn't updated anything in my Android installation for quite a while. I needed a feature and ran the SDK Manager. Besides what I needed I basically checked everything it wanted to update. Afterwards my R.java disappeared in Eclipse.

To make it short, in the SDK Manager there was a new entry "Android SDK Build-tools" that I guess wasn't there the last time I had updated. It's kind of an obvious name, really. After I installed that one Eclipse gave me my R.java back.

Junie

Answer 21

java .... than debug.. or Remove the 'import R.java' line from your code. Its done by Eclipse in order to solve the problem. Go to "note_edit.xml" file. Wherever you find "match_parent" as an attribute value, replace it with either "fill_parent" or "wrap_content". Do a clean build. R.java will be generated automatically

Skittish