No generated R.java file in my project [duplicate]_问答_开发者

This question already has answers here: Developing for Android in Eclipse: R.java not regenerating (64 answers) Closed 8 years ago.

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 androi开发者_StackOverflowd.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.

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.

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.

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

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

`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 !

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

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

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.

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. "

Do you have installed the android plugin ?

Your project must be of the android type.

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.

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....

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

The target sdk version is not selected in the project settings

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)

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

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

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.

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.

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.

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.

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.....

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.

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