I created a new xml file, and had an errant ? in it that prevented R.java from regenerating. I tried Cleaning the Project, and Fixing the Project Properties but no luck.
Then I realized the XML was creating the R.java from recreating itself, so I deleted the XML file and the R.java was back.
Now though, I am getting an error on all the calls to R.. calls saying that :
cannot be resolved or is not a field
So, for instance I have
setContentView(R.layout.detectlayout);
ERROR: detectlayout cannot be resolved or is not a field
for all of my calls to 'R.'. Any ideas?
I have tried all of the suggestions on SO already to no luck =/
Look at the 'import' section of your code. Since you deleted your original R, chances is Eclipse help you to fill in the R as com.android.R instead of com.yourproject.R
I also sometimes have problem in Eclipse Resource stuff, sometimes I found turning off and on the "auto buiild" function may help, or simply restarting Eclipse may sometimes help. It's kind of buggy under Mac OS.
This can happen if .R is imported. Eclipse will automatically add it sometimes when you have difficulty with with R.java
first don't bother deleting the R file it not going to make things better only worst lol
as you said you some times need to clean the project
when you start modifying resources its good to select the root of your project and do a alt+shift+o to reload all ressources
then f5 to refresh the tree
then clean the project
you also have to check that eclipse is set to build automatically (Project->build automatically).
Related
On my Android Studio, it says it "cannot resolve R symbol." So I tried rebuilding it and cleaning it several times, but it's still like this.
What do I do?
Here's my code- The first url shows my code
My gradle says these two things are the problem, but I don't understand it. Here's what my gradle says:
This happens quite often to me too. I usually end up going File> Invalidate Caches and Restart which fixes it 99% of the time
1) Please check buildToolsVersion or downgrade it.
2) make sure your appcompat compile library is included in build.gradle
3) Try to restart Android studio with invalid caches and restart
4) clean/rebuild project and then synch it.
Hope it helps
In your activity_horizontal_margin you are probably referencing a string from values.xml which doesn't exist, make sure use #+id/.... when this is a new value not declared in values.xml and are instructing the parser (or call it the builder) to create a new entry in R.java, thus you have to include a + sign.,use #id/... when you want to reference an already existing resource in values.xml so parser links this to the already created id in R.java. you can now rebuild your project.
I know this question has been asked & answered before. But, none of those answers work for me. Eclipse crashed in the middle of a build and keeps erasing the R.java file. I have tried to clean and rebuild. Does not help. I was using SDK build tools 19.0 upgraded to 20.0. Does not help. I didn't touch anything in the XML files and I do not see any errors in the XML files.
Try another IDE e.g Idea and check if this is due to your Eclipse malfunction not your SDK that you have updated recently
I my case there was something wrong with my XML usually my layout files, when you have a problem in your XML files the clean option does not work properly, check your XML files ( layout and manifest ) and after that clean your project.
Hope this help you
I did get my R.java back. There was a jpeg for another project stuck in a drawable directory. Don't know how it got there. and, still lots of unexplained errors though.
All my other errors were from switch statements using R.something_menu.icon for cases handling user responses. I got a message that as of ADT 14, switch statements can no longer be used. I had to migrate to if...else It works. Don't know why. But, it solved the problem & saved my code.
I was having a project open in Android studio. It was generated by the wizard and working fine.
I did some small changes to activity_main.xml and when I changed back to MainActivity.java i get the error in several places that it cannot resolve R. I might have done something to cause this. But I´m not sure what since it appered when I edited the xml.
Does anyone know what might be the solution to this?
I can find the R.java in r/release/packege/com/ and it looks fine.
Most of the time it is due to a bad XML file. XML files can be layout files, value files, or the Manifest file. Please check your xml files and try to rebuild the project. Sometimes cleaning the project and rebuilding it also works.
In addition, make sure you do not have a drawable with an invalid name. I had a drawable with a numeric filename and that didn't sit well with Android so it failed to compile R.java.
Downgrade Your Gradle Plugin Version
No amount of cleaning, rebuilding and restarting would do the trick for me.
The only thing that did the trick was downgrade our Gradle version from 3.4.0-alpha02 to 3.2.1.
So, instead of:
dependencies {
classpath 'com.android.tools.build:gradle:3.4.0-alpha02'
}
We used:
dependencies {
classpath 'com.android.tools.build:gradle:3.2.1'
}
After making that change and then doing a Gradle sync, everything worked.
Not sure if it's related to the alpha release or to that version or if changing your Gradle version at all just forces a refresh that otherwise cannot be done with the other commands, but there ya go.
Make sure in your AndroidManifest.xml the package name is correct. That fixed the problem for me when my R.whatever was marked red!
Try to clean the project by doing the following:
If you are using Windows, open CMD, cd to your project directory and run gradlew clean.
I just had this problem and the reason was that after editing the layout android studio automatically added an import to the source files:
import android.R
Of course the main R class has not all the symbols in your layouts, which made everything a red mess.
Removing that line solved for me.
EDIT:
Seems like eclipse had the same problem early on.
I sometimes get this after updating Android Studio. Not always straight away but after a while (perhaps after a restart of the program).
Here is what has worked for me: Tools - Android - Sync project with Gradle files.
For some reason just clicking the "Sync now" link that shows up after changing the build.gradle file has not done any change for me. Even though the messages says approximately the same thing.
I had the same problem because in my strings.xml I forgot to escape a apostrophe. Use " \' " never " ' " in xml file!
I had that same problem crop up, too (most recently while I was at lunch--came back and WTF?). And since this was a simple Hello, World program, there wasn't many places these errors could hide. The XML files looked fine--I hadn't even touched the manifest. A clean did nothing.
So I commented out a section of my layout.xml to try to narrow down the problem. Sure enough, the errors went away.
And then I simply UNcommented out exactly what I had commented...and everything was hunky-dory. Strange! Perhaps there was some lingering issues that needed to be touched in order to cause a rebuild of the layout file. You'd think basic stuff like that wouldn't happen these days, but they do.
One more thing! It's possible that something may happen to Java as well. It's very hard to know the status of the Java run-time environment; just easier to start again. So here's one more thing to try: restart your computer, restart Android Studio, AND THEN Invalidate Caches and Restart. Yep, the whole-hog.
When all else fails restarting android sometimes helps. During the start files are loaded afresh and this enables detection of the R
This problem occurs when you rename the package name.
After renaming the package name, you must change the older package
name to a newer one.
For me it solved the problem once I changed that.
After that, you might get errors in xml files, that you have to change
the package name there also.
That's it.
I just had the R problem and after a few hours found that the problem was my regional spelling as used in one of my xml files. The problem word was behaviour, which is spelled behavior by Americans.
I am Australian and we are taught ye olde English way of spelling certain words and so I looked past it a number of times before the penny dropped.
Its a small thing, but it can easily sneak up and bite you on the nether regions and is hard to spot and can waste a lot of time.
In my case I had just added some new image files to the drawable folder and accidentally put a GIF in there with my PNGs. I had not incorporated them into the project at all yet. I removed the GIF and then did a clean and rebuild. That fixed it for me.
I had this exact problem when importing a Udacity Example Program. The Message Pane in Android Studio said the error was failing to load a .PNG in a sub-directory deep in the Project Files.
Turns out the PNG with all of the sub-directory path names was greater than the name length limit defined by Windows 7 (260 characters). I gave the Project a shorter name - to free up some space - and then Android Studio happily compiled.
After you tried make project, clean project, rebuild project but still doesn't work.
Try restart Android studio
Suddenly my Android app is compiling with loads of errors in Eclipse. When I use Project-Clean the console shows it processing until 'Writing symbols for class R' then it pauses for around a minute and finishes with 'Nothing to pre compile' This behaviour follows adding several new strings to my strings.xml and replacing strings in the code with :-
getResources().getString(R.string.name of string);
Any ideas? Would it be safe to delete the R.java file to force it to rebuild perhaps?
I faced a similar issue. I had missed putting a plus sign in android:id="#+id/GoTo". Everything was fine after I put back the missing plus sign, cleaned and rebuilt the project.
When you use eclipse is very important after you change something in strings.xml to save that file and also rebuild !, if you have checked the option for build automatically than is enough just to CTRL+S if not you have to rebuild manually , cause your R.strings values are not jet updated
Check if you import the right R file. It should be your projects file, not android.R.
Maybe your listing is not exact code but if it is, then resources names can't contain spaces. (I am talking about R.string.name of string)
This is my currently todo list when I have that kind of problem:
Refresh main project
Clean
Build All
if it wont work again. Close Eclipse -> repeat from 1.
R cannot be resolved
R.layout.main cannot be resolved
error is repeating to me and i cant run any of my android program
pls give any instruction
also probably delete this line which sometimes creeps up :
import android.R or something like that.
Are you using Eclipse?
Try project -> clean
Otherwise: check your console in the bottom for errors that need fixing before your R is build
I just had a reoccurence of the dreaded "R cannot be resolved" error, and I went through all the usual fixes; make sure all resources have lower case names, do a clean, make sure there isn't an import android.R lurking somewhere... no luck.
After a couple of frustrating hours I realised I had saved a PaintShop Pro format file (something.psp) in a resource folder in the file system and Eclipse was pulling it into my res folder. Not being a .png, it choked, and that seemed to cause the problem. As soon as I removed the .psp the error disappeared.
Hope this helps prevent someone else pulling out their hair.