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I download a Android open source code from web.
When I import it to library,it don't have a "gen folder",so I manually
create one then I use "refresh" and "Project clean ..."
The eclipse still don't auto generate the R.java file.
And why I can't "" import com.codeminders.ardrone.ARDrone;"
I already have the folder in my project.
How can I fix this?!
https://dl.dropbox.com/u/33585022/Screen%20Shot%202012-11-22%20at%208.41.05%20AM.png
This means that you have an unresolved build pathing problem or there is an error in one of your xml files.
After looking at yoru image, the package that you are referencing does not match anything in what you have in your explorer. It must have a matching package reference.
I think you are missing a jar file or a project library that you used. Try adding them in your build path.
I had same error, and i fixed this. Remember that i shouldn't modify or create a R file. I think you got an error with Eclipse. Try download new Elipse and exactly Android SDK. Good luck
I'm getting the dreaded package R does not exist, it's killing me.
The code is fine I have apps in the market running the code.
Now it's effecting simple webview applications. o.0
R.string.app_name is error'd my main.xml and string.xml is fine. I'm sooo confused.
I re opened an older version to "borrow" some code and it was flooded with R. errors. I did a clean and nothing changed except for import R.android being added at the top.
I even loaded into Netbeans and I get the same thing. Clean is not working. Can I write the R.java file myself?
What is this R thing? isn't R. supposed to correspond to R.java
For anyone who ran into this,
I refactored by renaming the namespace folders. I just forgot to also edit AndroidManifest and that's why I got this error.
Make sure you check this as well.
Just to make this simple:
import your.app.package.R;
Of course, replacing your.app.package with your app package.
In all the classes which use R resource references, remove any other import with .R, i.e. import android.R;
TL;DR, if you get the error "package R does not exist", possible reasons are
some error in the XML resource files
-> fix XML errors
the current package is different from the R package (see package
attribute in AndroidManifest.xml)
-> import R class, e.g. import com.example.android.R;
-> or use the appropriate package in your source, e.g. package com.example.android;
-> or change the package attribute in AndroidManifest.xml to
<manifest xmlns:android="..." package="com.example.android" ...>, if that's appropriate
the used R ids are from the system resources
-> do not import android.R, but prefix the offending ids with android., e.g. android.R.layout.simple_list_item_2
You may import android.R instead of prefixing the ids of course, but then you cannot import the application R class anymore and must prefix the application ids, e.g. com.example.android.R.id.main_menu.
The R class is generated automatically from the application's
resources. It contains the ids for these resources and is contained
in the package named in the
<manifest>
tag in the corresponding AndroidManifest.xml file.
If there are no errors in the resource XML files, the R.java source
will be generated in a package subdirectory below gen/ and compiled.
There is another R class located in the android package. This android.R class contains some nested classes, which in turn contain ids and other values for system resources.
To use a class in Java, you must name the class with the whole
package, e.g.
java.util.List<Object> list = new java.util.ArrayList<Object>();
or import the class and then use it without package
import java.util.List;
import java.util.ArrayList;
List<Object> list = new ArrayList<Object>();
You can also use a class without naming the package, if both the
current class and the used class are in the same package, e.g.
package com.example.android;
public class A {
/* ... */
}
package com.example.android;
public class B {
public void useA() {
A a = new A();
}
}
Never, ever try to write the R class yourself!
Have you imported the right R class in your files?
Doing
import android.R;
instead of
import com.example.R;
seems to be the problem for a lot of people. After cleaning and building, my classes sometimes import the wrong one.
if you are developing in android studio and refactored the package name then you should change the package name in android manifest and app gradle file.
applicationId "change here your package name"
and in manifest file
package="change here your package name"
R.java is an autogenerated file, it usually does not get compiled if you have errors in xml file.
No You cannot write your own R.java file, it has to be generated by the resource compiler.
Check for errors in all your xml files.
I suppose it used to work but now it doesn't..
This can happen if you change PACKAGE name inside your MANIFEST file
<manifest
package="com.example.android...."
If you want to change package name
Change the package name manually in the manifest file.
Click on your R.java class and the press F6. It will allow you to move the class to other package, and all references to that class will be updated.
The R class is Java code auto-generated from your XML files (UI layout, internationalization strings, etc.) If the code used to be working before (as it seems it is), you need to tell your IDE to regenerate these files somehow:
in IntelliJ, select Tools > Android > Generate sources for <project>
(If you know the way in another IDE, feel free to edit this answer!)
I just ran into this error while using Bazel to build an Android app:
error: package R does not exist
+ mContext.getString(R.string.common_string),
^
Target //libraries/common:common_paidRelease failed to build
Use --verbose_failures to see the command lines of failed build steps.
Ensure that your android_library/android_binary is using an AndroidManifest.xml with the correct package= attribute, and if you're using the custom_package attribute on android_library or android_binary, ensure that it is spelled out correctly.
This might happen when using R in sub packages
Example:
com.example; // -app package and main Resources mapped to app package
com.example.order; // -sub package
in the sub package if you need to access a resource like,
R.Layout.orderLayout - Here R will not be available.
To solve this you would import the R from main package. ie.
For files in the com.example.order folder/package you would import
package com.example.order
import com.example.R;
Delete import android.R; from all the files.. once clean the the project and build the project.... It will generate
Sample: My package is com.example.mypc.f01, to fix error you add line below to Activity:
import com.example.mypc.f01.R;
Below are some technics which you can use to remove this error:-
Clean your project, Buidl->clean Project
Rebuild project, Build -> Rebuild Project
Open manifest and check is there any resource missing
Check-in layout to particular id if missing add it
If the above steps did not work then restart android studio with invalidating the cache
This is how i solved it
After several failed attempts of Build -> Clean Project followed by Build -> Rebuild Project
Step 0 : Made sure Package name is correct in AndroidManifest.xml
in my case it was
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myproject">
Step 1
Place the cursor before myproject and press Shift + F6 -> Rename Package -> Give your new package name and under Scope select All Places -> Refactor
Step 2 : Turn Off Auto Import
For Windows its File -> Settings -> Editor -> General -> Auto Import
Under Java
uncheck Add unambiguous imports on the fly
uncheck Optimize imports on the fly
Apply and save
Step 3: Clean and Rebuild
Build -> Clean Project followed by Build -> Rebuild Project
Now when you get the error during Build. Open the File that says R.java is missing or Cannot Find "R" class
Step 4:
Open the file and Go to its imports section in the code and add manually import com.example.myproject.R;
Repeat the same for all the files mentioned in the Build Section that has this error
Clean and Rebuild and you are good to go !
In my case I realized that I was creating multiple packages in the project. Within the Android Manifest I found that the provider name was incorrectly holding the value of MyContentProvider instead of .provider.MyContentProvider. My main package (with the UI) was co.companyname.database.provider instead of co.companyname.database.
Then on the import statements for the affected class I simply right-clicked and asked Android Studio (0.8.6) to optimize my import statements. I also noted that if you search for .R in the AS search bar at the top right corner of the IDE you can find an auto generated R.java file that is part of your package. At this point you don't have to change anything. Studio should fix up the project after you correct the Android Manifest file and rebuild.
One other item is that in one class I was doing making use of the toString().length() to evaluate a string but swapped those out for TextUtils.IsEmpty (stringVal); Can't think of anything else that I did to resolve the issue.
Hope this helps someone.
NB - All of this is with AS 0.8.6
P.S.
R.java is auto-generated so read the header:
/* AUTO-GENERATED FILE. DO NOT MODIFY.
*
* This class was automatically generated by the
* aapt tool from the resource data it found. It
* should not be modified by hand.
*/
When I experienced this, I created a new project, and copied the files from my old project to my new one.
Start a new project
Add the old files into the new project (copy and right click on Layout, drawables,com.packagename,...) to paste my old projects files
However, I still had the same problem: R does not exist. Then I realised that I had copied and pasted Manifest from my notepad into Android Studio manifests and I hadn't changed the package name in the manifest file.
Therefore, once I changed the package name in the manifest to the new project name, the new project I'd created worked fine.
Below are worked for me.
In AndroidManifest.xml file, check whether the package name is correctly typed.
import com.example.appName.R; (import package _name.R;)
If the first step is not worked try the second one.
After upgrading to AGP 7.2:
For the poor fellas that have upgraded to AGP 7.2 (stable version!!):
the AGP Upgrade Assistant will remove the package name from the Manifest
It is no longer needed, as it'll be just on the gradle file
But SafeArgs dependency still doesn't get that correctly though.. (link)
Hopefully you'll waste fewer hours that I did.. :)
What files are you importing into the files getting the R error?
My understanding of the R file are that they are automatically generated reference lists to all attributes within the Android app. Therefore, you can't change it yourself.
Are you using Eclipse to build this project?
Were the older projects getting these errors made before updating Eclipse?
What are the references that are getting errors?
Check to make sure that you've not imported another R file from other copied code in another app.
I run into this problem every time I switch computers and try to import old projects from files transferred via a USB.
My workaround is to just create a new project and copy (drag) the files into the IDE (currently using Netbeans) and rebuild. This is an annoyance and a bit of a hacky solution, but it fixes the problem.
If this happens to you, worst case is you might have to backup your files, delete the project, and just drag the files in there and recompile. Hopefully it won't come to that but that would be your nuclear option.
You may try
Android Studio top menu > File > Invalidate caches / restart...
Click on invalidate cache / restart button to restart your project
Resolve R.xxxx.xxx again if some of the fragment class R class didn't resolve properly
then rebuild your project
Hope it helps
Just got rid of the error in my project. I had imported a sample project, I had changed the package folders but I had not updated the package in one of the java files.
Most likely cause of this error 'package R does not exist' is that the package name in Java or manifest file is incorrect. Make sure it is correct and in sync and then do a clean build.
This error is 100% due to error in xml file. You can check that particular error in Logcat->error. and then solve that. If the xml error is solved the application would run. It's mostly arises when you copy a code from other source .In my case there was a error in Button in a xml file. I haven't typed Button correctly .If you solve that error your and your application would run smoothly. If yet it shows this error than don' worry and move forward.
finally found the solution.
Go to File>Invalidate Caches
Now "Check" Clear file system cache and
Local History & Clear VCS Log caches and index
Now Click on "INVALIDATE AND RESTART"
If you encounter this error in Android Studio:
Check the Gradle module file(s) -> defaultConfig -> applicationId setting.
Check the AndroidManifest.xml -> manifest package tag.
Check the package declarations in all src java files.
Sync, Clean then Rebuild with Gradle.
NEVER build your own R file. R is auto-generated from your source java files and build settings.
I had: "error: package R does not exist" and assumed javac
didn't have access to R.java.
So I appended %PROJ_LOC%\gen to sourcepath, and it worked!
SOURCEPATH=%PROJ_LOC%\src;%PROJ_LOC%\gen
I'm not using Android Studio or Ant (or XML).
If this error appeared after resolving merge conflicts, simple Build -> Clean project could help.
Sometimes, it gets solved when you just re-import the project into Android Studio.
Wrong path: Project "cashes" the pointers to the images and if you have made name changes to the path for example Refactored package or folders. Then just simply write the R letter again and the editor suggests the right path and it will work. In this case your filenames are right and the content that is referred in the R. pointer is present but the path is wrong, thus clean and build won't work.
Another case of R. breakage is Annotations Processing.
Some processing could refer to classes located in certain folders or folder levels. If you move required classes to other location, you can get R. as an unknown class.
Unfortunately the error-pointer to this problem is not evident in Android Studio.
My PC went to sleep while battery was low. But when it recovered I found R.java file missing from my gen folder. My entire application is under crash.
The error is shown below:
If you recently added a new resource file and happen to use upper case letters in the file name, change the file name to lowercases and rebuild your project. That is what happened to my project.
The R.java file should be regenerated every time you do a rebuild of your project.
Clean the project,
Go through your code and remove all references to android.R.*
So when your R.java is corrupt or missing Eclipse tries to be helpful and thinks that the references in your code for R.something are missing the import file and inserts the android.R.* to your import list.
If you are using IntelliJ it has a rebuild R.java command.
If it is still missing then it means that something in your code is preventing it from being built. Pay attention to resource file names etc. Usually you can sport these naming problems in console view of eclipse
There are possible chances, you have a problem in your layout xml or in your code.
Try looking at file that you had open in your eclipse when it went to sleep, and code snippet that you were working at.
Edit:
R (resource file) regenrates at every rebuild of your project. For some error in your project your project wasn't able to build that why your R file is missing. All that you need to do is to fix issue in your files, code and xml files.
I got the same issue. Nearly I spent whole day working on it to figure out the reason and tried all the 100 solutions provided in the blogs. But nothing helped!!! After setting up a new workspace I figured out. Remove unnecessary libraries in your project. You can check this by Project-> right click-> properties-> Android-> and remove unnecessary added libraries. It worked :) Hope it helps some one.
Ok,
I am working on a new app and everything worked fine as long as I used a Relative View. However, I want a tabbed layout so I switched what I had (not much so far since I just got it reading from a DB and settings working) over to a tabbed view. Since that time, any class that has any R. statement in it has an "R cannot be resolved" error. I am following the tutorial from the Android "Hello Views" tutorial so I am assuming that isn't the issue (but it could still be).
I have a few suggestions:
Make sure you don't have any other errors other than the R-related errors. Right-click your project folder in Eclipse, Android Tools -> Fix Project Properties.
Check to make sure you have the correct R imported. Sometimes the default Android.R can be imported.
Check for errors in your layout XML files.
You can try to "clean" your project.
The default tech solution helps sometimes: restart Eclipse (seriously)
If you have an error (something in your XML maybe, or something else), R cannot be compiled. If this is the case, try to find the first error noted. If you fix this, R will be compiled and found. If necesairy, use point 1. and 2. after fixing stuff.
Remove all "import R" stuff in the import sections. You don't want that.
If you're using Eclipse, trying giving it a kick by doing a Project/Clean and re-building your project. It sometimes has random trouble with the classpath on Android projects.
Along with the great suggestions in the previous answers, make sure your Android target is set:
Right-click on your project
Choose Properties
Choose Android in the left menu
Tick a box next to the appropriate Project Build Target.
Click Apply and OK
Edit: A year later I found another cause. I had a .jpg image in my drawable folder with the same name as a .png image. Referencing this image in my code must have confused the program and it gave the "R cannot be resolved" error.
If anything in your 'res' directory is named using illegal characters, this can happen.
Note that android only allows lower case letters (no capitals!!!), numerals, and the underscore. THAT'S ALL!
Almost every operating system allows other characters, so moving a file into your 'res' directory can easily create this problem.
Fix? Rename the file. This is done by right-clicking the file in your package or project explorer and selecting Refactor->Rename. You may need to clean your project after, but beware of the dreaded "import android.R" that may creep in.
Good luck!
-scott
Check that all of the strings you think you're using (e.g. "#string/Hello_world") actually exist in your strings.xml file. I got the OP's error after declaring a menu item using android:title="#string/Navigation", but I hadn't added <string name="Navigation">Navigation</string> to strings.xml
I had the sample problem too and this worked for me.
1.) Check for any errors in your Layout XML. Especially when it comes to text and titles
You should use
android:text="#string/hello"
instead of
android:text="hello"
.2) Clean your project
.3) Restart Eclipse
You should import your own projects R class rather than androids default R class ie.
your.app.package.R
This will make the values defined under the res folder in your class . After that refresh and then clean your project .
In my case it was caused since I refactored my project and moved some classes inside a folder structure. Those classes couldnt find the R as usual, since its based on the root source folder.
You need to make sure you import R. If your main package is com.example try importing "com.example.R" at the top of your files. For some reason eclipse does not do this for you.
This question already has answers here:
Developing for Android in Eclipse: R.java not regenerating
(64 answers)
Closed 9 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 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.
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
or
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