I created new android project in eclipse and created MainActivity.java and activity_main.xml files but the activity_main.xml file is not recognizing. Project-> clean-> clean all project does nothing . I deleted import android.R does nutting. What should i do? see the screenshot. R not generated in gen folder
Generally in android there are two different R files you can acces:
The android.R - provided by the android platform
Your projects R - holding your resources
You have to import your R file, not the android.R, in order to access your layout.
This is done using your package name on import like this:
import your.package.name.R;
The android.R is used for resources provided by the android platform, while your R file contains the resource you added to the project.
Try to clean you project and build. it will work. Kindly remove import android.R; in your activity
'R.layout' is not able to find your layout that means 'R' is not pointing to your application resources. It possibly is pointing to android's resources because this R is of android sub-system.
Look at the import statement, R probably will be of android.R. So you need to tell that you need your R file to use your resources. So you need to import yourpkg.R.
If your layout contains some error then your R would be created in build process. So if your R is not getting created. Check your layouts and fix the issue in layout files.
This post may help in getting to know about Why R file is not generated.
In my new project I always have to import:
import com.abc.R;
or the problem: "R cannot be resolved to a variable" appears.
But in my other project I don't have to do that.
What is the difference and is there any problem?
This might happen when you have an error in your xml layout and then you try to clean the project, you get this error.
Try to build the project, if it doesn't work, start a new one and copy the contents. Now that should work.
In general, to make it work:
use the Ctrl + Shift + O command to "Organize Imports" and generate
any missing import statements. Sometimes this would generate the
incorrect import statement which would hide the R.java class that is
automatically generated when you build.
R is a generated class. If you are using the Android Development
Tools (ADT) it is generated whenever the project is built. You may
have 'Build Automatically' turned off. Turn it on and build your
project.
Mistakes in your xml views could cause the R.java not to be
generated. Go through your view files and make sure all the xml is
right! Remove, if any import android.R;
Restart your IDE.
Perhaps in your other projects the classes referencing R are in the same package as R?
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.
I have a problem with R in android. I have a project with some packages. I changed the name of one package. I saw that the package with the same name was in "gen" folder. When I changed the name, I cleaned the project and this package disappeared from "gen" folder. Now I have error with
R cannot be resolved
and in all classes I have errors with R. How I can repair my problem?
So i think this is answer
Eclipse sometimes likes to add an "import android.R" statement at the
top of your files that use resources, especially when you ask eclipse
to sort or otherwise manage imports. This will cause your make to
break. Look out for these erroneous import statements and delete them.
Reference.
And try to clean your project and if you have
import android.R;
remove this line and clean it again.
remove
import android.R;
and do Project > Clean...
Remove this import from your code if it is there.
import android.R;
Clean your project and rebuild the solution again.
If it isn't what the two other answers are, I've had a similar problem that related to me having an error in one of my XML files. Since the XML file has an error, eclipse fails to build your project. A failed build somehow messes up the path to the R.java file. So if you clean up your XML files and build the project, it should fix itself.