This question already has answers here:
R cannot be resolved - Android error
(108 answers)
Closed 9 years ago.
Hey everybody i know this question has been asked many times before.
i have tried all the possible solutions given but i still havent been able to get the solution.
Here is my code:
package com.example.newp;
import com.example.newp.R;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
PS: Ive tried cleaning my project. I removed import android.R;
Its still not working. Please help out. Im unable to progress forward because of this bug.
This should work. Make sure that your activity_main file doesn't have any compilations errors (Red marks) before you follow these steps.
First remove the line
import com.example.newp.R;
Still error persists, then make a single line comment to setContenView();
//setContentView(R.layout.activity_main);
Now clean the project from menu Project -> clean.
Remove comment line to setContentView().
Now check that you don't have any errors.
If problem persists, restart your eclipse.
Check your res folder. If you have resources errors, than fix them and after that try Project->Clean.
I found a pretty handy guide that provides a lot of possible solutions to the R problems.
Related
Okay, this is driving me absolutely nuts. Relevant info:
I'm using Android Studio
I'm trying to set up a gaussian blur from here: https://stackoverflow.com/a/14556162/2170400
In my src/com/myprojectname folder I have, among others, the following files: AndroidImage.java, IAndroidFilter.java, ConvolutionMatrix.java and GaussianBlur.java. In IAndroidFilter.java I need to
import com.myprojectname.AndroidImage;
However I get a message saying "Cannot resolve symbol 'AndroidImage'". In the auto-complete menu that pops up while I'm typing the import statement I can see EVERY SINGLE CLASS in my src/com/myprojectname folder EXCEPT AndroidImage, which I can clearly see in the explorer.
I've quit and re-opened Android Studio several times, I've re-synced everything, I've deleted then re-created the AndroidImage class, I've tried to import AndroidImage in other classes with the same failed result as in the IAndroidFilter class...
Why is it that I can't import this class? Seriously, why? I'm at a total loss for further fixes to try.
Check to make sure your AndroidImage.java file has this at the top:
package com.myprojectname.AndroidImageProject;
Or whatever the package is.
I am brand new to android development so please bear with me. I have encountered a problem when I create a new activity. In the newly created activity there is the auto-generated overridden method 'onCreate':
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_find_contact);
// Show the Up button in the action bar.
setupActionBar();
}
On the line setContentView(R.layout.activity_find_contact);, I get the error: activity_find_contact cannot be resolved or is not a field.
I have looked up other questions on this topic. Some say to just restart eclipse - this didn't work. Others said to try cleaning the project - this didn't work either. The most promising answer said to delete the line:
import android.R;
I tried this, and of course then R gets the error: R cannot be resolved to a variable. So I followed the advice to import your.application.package.R; - which in my context translates to import com.example.databasetest.R;. However this just brings up the error the import com.example.databasetest.R; cannot be resolved to a type.
So now I'm stumped and back to square one. Any ideas?
R files are automatically generated.. so you don't need to import it or do anything. The error is because there is something wrong in your xml file or files.Got through your xml files and see if you can find any errors.
These errors might even be typos.So make sure all of it is correct and cleaning and running the project again should get your code working
Do not use the following import
import android.R;
This errors comes because when we create new app we delete hello world textview but that is referenced in strings.xml in res > values > strings
go to that and remove hello world , clean project and errors should be gone ...
This question already has answers here:
R cannot be resolved - Android error
(108 answers)
Closed 9 years ago.
I have tried finding the answer to this question on here before, but none of the fixes have worked for me. Basically, my Android project is refusing to run - even though I haven't edited it at all from the default program that is given when you make a new project.
I have a red line under R on Eclipse, throwing up the error "R cannot be resolved to a variable". It suggests that I import android.R, but when I do this, another red line comes up, this time under activity_main, saying it "cannot be resolved or is not a field".
I have absolutely no idea what is going on here, and am not prolific in coding or programming at all, so any answers in absolute layman's terms would be really great. My code so far is below:
package com.randomproject.thebasics;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
Try doing a Project->Clean, and then a full re-build (Ctrl+B). Eclipse sometimes goes a bit wonky with auto-generated files.
As noted in the comments this question has been answered thousands of times. Well, ok, only tens of times. There are two possiblities:
1) Resource error
There is an error in your manifest or one of the files in your res directory. The resource compiler cannot run and there is no R.java class in the gen directory. Look in the gen folder, if there's no R.java file there, this is your problem.
2) Bad import
Sometimes in an attempt to help you, eclipse will add the import android.R to your imports and then collapse the import section so you can't see it. None of your references to your R.whatever resources will work after that. Check the imports. Delete android.R if it is there.
I have a launcher for people with bad eyesight and a simple music player, this is my second APP so bear in mind I'm a complete noob in android and eclipse.
I tried to merge both my launcher and music player. I added the activity to the manifiest with a different intent, copied layouts and drawables to the launcher project and I added the player's package inside my /src folder.
Afterwards on the first lines of com.easyplayer.java I got this error:
import com.easyplayer.R; // the import com.easyplayer.R cannot be resolved
This is the only bug I'm getting so I suppose I did everything else fine. I imagine R must reference the player's layout, but I'm not sure how to fix it (cleaning/rebuilding doesn't work). What is the R class? And what can I do to fix this?
The R class you see is auto-generated by Android. It is a utility class that contains references to all the resources in your project. There is a few answers detailing its contents here.
You mentioned you performed a clean of your project, but you need to do a full build as well to regenerate this file.
edit: The import of the new code may have somehow invalidated your xml files. Check to see if there are any errors there, which could be preventing the R file from being re-created during a build.
if you have several packages like, com.example.app.package1 and com.example.app.package2, then import the R.java file like,
import com.example.app.R;
And if you already have import android.R; then please delete that and save the file and clean the project, problem will be solve...:)
I just started playing around with android development, and already with just an attempt at making a button, I have encountered a problem.
The error I'm given in the following code is right on "R.id.button1".
It says id cannot be resolved or is not a field.
Do I need to manually reference every single object I make in the layout xml file? I found that this did work, but it does seem to be a bit much for every button I want to make...
package com.example.helloandroid;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class HelloAndroid extends Activity {
/** Called when the activity is first created. */
private Button button1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button1 = (Button)findViewById(R.id.button1);
button1.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
finish();
}
});
}
}
I've been wasting a lot of time (two weeks) because of the same problem until I discovered the problem wasn't mine but Eclipse's.
I guess there's a lot of people with the same problem.
Just try this: Save your project, close Eclipse and then open it again. So simple.
Do I need to manually reference every single object I make in the layout xml file
Yes, otherwise you won't be able to do anything with those views. It's not that bad actually. So, each time you create a view in your XML, and you want to reference it, put an ID:
<View
android:id="#+id/the_id"/>
And then, from your code you can reference it using the R class. You can type, in the example, R.id.the_id and then Ctrl+Shift+O to make Eclipse auto import the needed files.
You can speed up your productivity by using frameworks like Roboguice; I think it's for lazy people, though.
This answer is not applicable to this question (looking at code you have provided). Just adding it if someone else stumbles here and above mentioned answers do not help.
If cleaning (Project --> clean) doesn't helps or saving and restarting eclipse doesn't help either, check for the following incorrect import.
import android.R;
Which Eclipse sometimes add by mistake on auto-import (Ctrl+Shift+O).
Remove that line (import) and it's done :D
Following this EXCELLENT tutorial , I encountered the same problem. After reading Carmello's answer (Sept 17, 2011. 07:23) I simply clicked File->Save All, and voila, 'button0' was automagically defined, and even syntax highlighted.
If "R.id.button1" is not defined, then you'll get a compile error, just as you saw. If you don't define this in the layout, then it won't be defined.
You don't have to specify every object you create in the layout, but you do if you try to reference it from "R.*". You can manually create buttons and other objects that are not specified in the layout.
I ran through the same issues for time being. Plz, do not forget to define as follows:
<View
android:id="#+id/button1" />
if you are using the id in your .java class.
Button b =(Button) findViewById(R.id.button1);
Being said that, the id defined in xml file must match with the id in findViewById().
Go to the 'R.java' file under the 'gen' folder and check whether your 'button1' is present under the class 'id'.If not,then this could be the reason you got that error.When you use the statement " R.id. " make sure that the is present under the appropriate class,in this case under the 'id' class.
R.id is a generated object that assigns int numbers to resources. Try this go to your gen/mypackage/R.java and delete the file. As you can see it is re-generated. This file provides static references where as the context is more of the dynamic state of your app. If you have syntax errors that will prevent automatic re-generation of that R.java file so you will get lots or R. errors. As everyone else has said you can click save all icon or ctl+shift+s on windows. You can clean the project project/clean and that will clean up 95% of those exceptions. Yes eclipse is buggy that way but netbeans does not support android that well. this link may help
Good luck
Do these things,anyone of this will help you
Project -> Clean,
Right click -> Fix Project Properties
Restart Eclipse
make some fake modification in manifest and save
check your console for any error message
check your drawable folder, check the image names satisfy the rules