i am editing mainactivity.java code file this error occur
R cannot be resolved to a variable
when i import R then their further more new error occurs like
bAdd cannot be resolved or is not a field
bSub cannot be resolved or is not a field
tvDisplay cannot be resolved or is not a field
kindly guide me how can i remove these errors
Project -> Clean : do it a few times until you see the errors go away.
Select "Build Automatically" so that every time you clean the project, it will be rebuilt. And yeah, make sure you are saving the file before cleaning it (I know it is weird but sometimes the errors refuse to go away until you save it and then Clean it). Make sure that there is no error in the files in the layout folder, as it sometimes prevents the auto-generation of the code in R.java
Also, make sure that your code in MainActivity.java does not have import android.R. Eclipse tends to add that when you are managing the imports.
R is a generated source that recreated while building the project. Make sure that the project is built (in eclipse, there is an option for auto build in project->build automaticcaly).
Do not import R. This is not the R you looking for.
The error causes due to your any of XML file contains error.So check all xml files and clean the project and build it.
Related
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 am writing code for my android application, i am adding using #+id/id_name in the code
But this is not getting updated in R.java
How can I update it manually and also how to give this 0x7f080007 numbering?
Never update your R.java manually. Clean your project and try, It will update your R.java file.
Make sure that there is no error in any of the xml file. If one of the xml that contain error R.java file does not update.
Check with following steps:
1. Check all of your XML,
2. Project -> Clean,
3. Right click -> Fix Project Properties,
4. Repeat.
5. Maybe try restarting Eclipse
Note: check R.java package imported in your project. If it's android.R just replace with your packagename.R
Never update R.java manually. Check you don't have duplicate ids, close eclipse, re-open it, clean the project and build (usually is automatic).
You definitely do NOT want to manually update the R file.
Try cleaning and building. If you get a lot of compile issues when you do this, then you have define something incorrectly in you resource folder.
Make sure the names of all your drawables are all lowercase with no numerics, make sure all xml files are properly formed.
Try this, I think you have imported android.R.Please remove below code in your project. And the clean and build you project
import android.R;
I moved my project on Eclipse by Right Click project > Refactor > Move. This caused (at first) an exclamation mark to show next to project name. So I restarted Eclipse. This removed the exclmation mark, but now my entire Activity file's R. references have errors. I tried:
Deleting R.java file and it regenerated automatically.
Cleaned the project few times.
Changed target build set back and forth. Still no luck.
There are no errors anywhere else. Just my MainActivity file inside src\com.* folder.
Are you creating Project name folder to another workspace on move??
Check if you are importing android.R instead of your generated R class.
From Using Eclipse:
Note: 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.
In the other hand, check if you have any errors in a xml file (but it shouldn´t allow you to generate the R.java file)
In the (Debug Configurations) menu in Eclipse,after I click on (Debug),it shows me an error: (R cannot be resolved to a variable).Am still new to Eclipse and this error confused me a little bit!
R.java is an automatically generated file which contains references to everything you have in your project. The fact it is not resolved may be caused by many reasons.
Check whether the gen folder and and R.java file exist. In case not, do the following:
Clean your project by selecting Project - Clean
if the R.java is not created, there can be an error in some XML file, check the console output
In your code, hover your mouse cursor over your R which should be highlighted red and check if Eclipse offers to import it (in case it does, select the R from your project and not from android package)
Let me know if it solved the problem
You can also fix it by creating new project and pasting all xml and java codes inside new project. It will recreate R.java so problem will solve by this way.
i almost face the same problem again. Few minutes ago i posted a question concerning that, the
R.layout.mylayout
is not recognised by eclipse despite that, the layout folder contains my xml file and the layout folder is located inside the res folder. the answer was to delete the R.java from the gen folder and clean the project and restart the workspace.
Now, i face the same problem again despite that i followed the previous steps to solve the error but the error which is that, the
R.layout.mylayout
is not recognise still exist and there is also exclaimation mark beside the project name.
is there any other ways to solve this problem
Project - > Clean
Select "Build Automatically" so that every time you clean the project, it will be rebuilt. And yeah, make sure you are saving the file before cleaning it (I know it is weird but sometimes the errors refuse to go away until you save it and then Clean it). Make sure that there is no error in the files in the layout folder, as it sometimes prevents the auto-generation of the code in R.java
Also, make sure that your code in MainActivity.java does not have import android.R. Eclipse tends to add that when you are managing the imports.
Please check you import statements.... If you have by mistake imported the android.R , then please remove it at once.... and then clean the project and see how it works...
Run the Lint tool. Right click your project and check under Android tools. check what is the issue using that.