I followed the Hello, Testing tutorial to the letter.
Yet, the following line produces a "com.example.helloandroid.R.id cannot be resolved" error:
mView = (TextView) mActivity.findViewById(com.example.helloandroid.R.id.textview);
Eclipse amazingly suggests 2 quick fixes:
Create field 'id' in type 'R'
Create constant 'id' in type 'R'
Can you help me understand what these fixes mean? Are these really the correct fixes? (why didn't the tutorial provide them, too?)
In HelloAndroid project, HelloAndroid.java
setContentView(R.layout.main);
Check your HelloAndroid project, in "gen->com.example.helloandroid->R.java" have the following code like:
public static final class id {
public static final int textview=0x7f050000;
}
if no, check "res->layout->main.xml". there is "android:id="#+id/textview" as follows?
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/textview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="#string/hello"/>
check these items, fix your HelloAndroid.java and/or main.xml if needed.
rebuild HelloAndroid project, and rebuild HelloAndroidTest project.
Are these really the correct fixes?
None of them.
What you have to do is importing the correct R class. Sometimes eclipse help you with that when you press Ctrl+Shift+O.
I am not an expert. But I can tell you that this problem also happened to me. Thanks to the comments above, I figured out that between the time I worked the Hello World tutorial and the time that I tried the Hello World Testing tutorial, I had tried the Linear Layout tutorial in the "Hello, Views" section. Following the Linear Layout tutorial, I changed main.xml.
I restored main.xml to the way in which the Hello World tutorial expected it and that solved the missing "id" problem.
Bit of a noob myself but recently came across this (or a similar) problem. You shouldn't have to import your R class because you give it an fully-qualified package name (com.yourpackage.R...) in the findviewById and the R class is public. However, if like me you had put both your project and your test project in the same package you are probably referencing your test R class not your project's R class.
Changing my test manifest to be com.mypackage.test instead of com.mypackage (and moving any subsequent misplaced classes to the new com.mypackage.test) fixed the problem (you may have to delete your test R class for it to be regenerated)
I had this problem as well while following the Android training for creating tests. None of the above solutions worked - a R.java class was continuously created within the MyFirstAppTest project, and this is the R class that was picked up in the MainActivityTest class. The only way that I could resolve it was to import the R class from the project under test (in my MainActivityTest.java file):
import com.example.myfirstapp.R;
Then the correct R class was picked up along with its id method.
Related
I keep getting this error. Should I just make id a field?
My code is:
public void onCreate(Bundle icicle)
{
super.onCreate(icicle);
setContentView(R.layout.main);
ImageView mainimage = (ImageView) findViewById(R.id.mainanim);
mainimage.setBackgroundResource(R.anim.mainanim);
mainanimation = (AnimationDrawable) mainimage.getBackground();
}
How exactly do you fix this?
Look at your import statements at the top. If you are saying import android.R, then there that is a problem. It might not be the only one as these 'R' errors can be tricky, but it would definitely definitely at least part of the problem.
If that doesn't fix it, make sure your eclipse plugin(ADT) and your android SDK are fully up to date, remove the project from the emulator/phone by manually deleting it from the OS, and clean the project (Launch Eclipse->Project->Clean...). Sounds silly to make sure your stuff is fully up to date, but the earlier versions of the ADT and SDK has a lot of annoying bugs related to the R files that have since been cleared up.
Just FYI, the stuff that shows up in the R class is generated from the stuff in your project res (aka resources) folder. The R class allows you to reference a resource (such as an image or a string) without having to do file operations all over the place. It does other stuff too, but that's for another answer. Android OS uses a similar scheme - it has a resources folder and the class android.R is the way to access stuff in the android resources folder. The problem arises when in a single class you are using both your own resources, and standard android resources. Normally you can say import at the top, and then reference a class just using the last bit of the name (for example, import java.util.List allows you to just write List in your class and the compiler knows you mean java.util.List). When you need to use two classes that are named the same thing, as is the case with the auto-generated R class, then you can import one of them and you have to fully qualify the other one whenever you want to mean it. Typically I import the R file for my project, and then just say android.R.whatever when I want an android resource.
Also, to reiterate Andy, don't modify the R file automatically. That's not how it's meant to be used.
Do not modify the R class. The error means there's something syntactically wrong with your XML layouts and R cannot be auto-generated. Try looking there and post the xml code you're not sure about, if any.
Edit : also: remove "import android.R" from imports at top of file (if there)
One possible solution:-
Summary: make sure you are using import com.yourpkgdomainname.yourpkgappname.R instead of import android.R
Details: The problem occured when I changed ID of a label which was being referred in other places in the layout XML file. Due to this error, the R file stopped generating at first. Eclipse is bad in handling errors with the layout files.
When I corrected the ID reference (with project clean few times and Eclipse restarts, I noticed that my import packages now has:
import android.R
Changing it to following fixed the error:
import com.example.app.R
I just fixed my problem right-clicking in the layout folder and clicking in the option Validate. Some windows will appear, you just clik OK and ist fine.
May be you created a new xml file in Layout Directory that file name containing a Capital Letter which is not allowed in xml file under Layout Directory.
Hope this help.
Just throwing this out there, but try retyping things manually. There's a chance that your quotation marks are the "wrong" ones as there's a similar unicode character which looks similar but is NOT a quotation mark.
If you copy/pasted the code snippits off a website, that might be your problem.
As Jake has mentioned, the problem might be because of copy/paste code.
Check the main.xml under res/layout. If there is no id field in that then you have a problem.
A typical example would be as below
<com.androidplot.xy.XYPlot
android:id="#+id/mySimpleXYPlot"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="10px"
android:layout_marginLeft="20px"
android:layout_marginRight="20px"
title="A Simple Example"
/>
Some times eclipse may confuse with other projects in the same directory.
Just change package name (don't forget to change in Android manifest file also), ensure the package name is not used already in the directory. It may work.
Just came across this myself.
Finally found my issue was with a .png file that I added that had a capital letter in it an caused exactly the same problem. Eclipse never flagged the file until I closed it and opened Eclipse back up.
What seems to be the problem, I just fixed mine in case anyone was wondering - Due to other errors i turned off build automatically, when i created a new project it said R.layout.main had an issue and needed to import R; So naturally as a novice, i did. Then i built manually and it had a problem with main. Try building your program as is, remove import R and it should be fine.
In main.xml (or wherever your item is defined) make sure that the ID for the R item is defined with #+id/... Here is an example with a button:
<Button android:text="B1" android:id="#+id/button_one"
android:layout_gravity="center_horizontal|center"
android:layout_height="fill_parent" android:layout_width="wrap_content" />
Each of these is important because:
# must precede the string
+ indicates it will create if not existing (whatever your item is)
I also had this error when I was working in a Java class once. My problem was simply that my xml file, with the references in it, was not saved. If you have both the xml file and java class open in tabs, check to make sure the xml file name in the tab doesn't have a * by it.
Hope this helps.
Just Clean your project so R will be generated automatically. This worked for me.
It gave me enough pain but I found the solution:
PROJECT ---> Clean ----> (Sele)
I had this problem but in my case it solved by restarting the eclipse.
For me the cause of the problem was that I had 2 images with the same name in my drawable-hdpi folder. Once I resolved that, then the R.java rebuilt itself and the problem was automatically solved.
select Project tab and click Build automatically so Build all option will be activated and then click on build all.and always start xml file name with lowercase.
I've taken a program from a book as a template. In activity_main.xml I have:
android:id="#+id/contactID"//and
android:id="#+id/contactName"
both are specified in separate text views.
Then in mainActivity.java I have:
int[] views = new int[] {R.id.contactName, R.id.contactID};
Neither variable is defined in the java file which looks odd to me, but that's what the book says...and eclipse says neither variable can be resolved or is a field so it won't compile. It's the correct contentView.
I'm guessing that R is supposed to pick these up when compiling - it doesn't. I've tried cleaning with no joy. Sorry if I'm missing something really obvious.
Check your import. remove android.R if its imported. And import your R. Also make sure that you do NOT have any errors in your xmls, or else your R will not be generated.
How do I fix this? I already tried removing the R.java and cleaning the project via eclipse, but it doesn't help.
FYI I am trying to get PhotoStream from here: http://code.google.com/p/apps-for-android/, but so far it has been very difficult to get things work.
Okay..... 5 mins later google tells me the correct answer...
http://www.fairtec.at/en/it-blog-mainmenu-16/168-the-type-r-is-already-defined
I just didnt search hard enough.
"The type R is already defined"
That's the message you get in Eclipse if you try to build the Funambol Android Sync Client.
Reason is that you have checked two Builders that try to generate the same class.
You just have to uncheck the Java-Builder from Project->Properties->Builders.
Then the application even works fine in the Emulator.
Delete the R.java from the src folder and rebuild the project. This file will be automatically rebuit during this process.
http://www.fairtec.at/en/it-blog-mainmenu-16/168-the-type-r-is-already-defined
click right to project click properties
Project->Properties->Builders.
unckeck java Builder
delete file R.java
You may want to change your package names. It looks like you are using a 'PhotoStream'.jar which has it's R.class defined at the same package structure as you.
Here is a link to the R.java from the project on Google Code. Notice you are using the same package:
http://code.google.com/p/apps-for-android/source/browse/trunk/Photostream/src/com/google/android/photostream/R.java?r=83
I had the same issue when I imported a project from work. Turning off the Java builder as suggested in the article you found fixed my problem, but when I made code updates they were not reflected in the running app. In my case there was an R.java in my source which I deleted and that fixed my problem.
In my case,
as i m not using any IDE for programming but using command line Android..
i had two xml files, one in layout and other in layout-land. i was using same id "XXX" for both but while declaring i made small mistake
android:id="#+id/XXX" (in layout xml)
android:id="#+id/XXX " (in layout-land xml)
please observe extra space in second id declaration, so while creating R.java they were different and in R.java i had
public static final int XXX=0x7f040046;
public static final int XXX =0x7f040045;
which are same, so please be aware of extra spaces. Thank you
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
I keep getting this error. Should I just make id a field?
My code is:
public void onCreate(Bundle icicle)
{
super.onCreate(icicle);
setContentView(R.layout.main);
ImageView mainimage = (ImageView) findViewById(R.id.mainanim);
mainimage.setBackgroundResource(R.anim.mainanim);
mainanimation = (AnimationDrawable) mainimage.getBackground();
}
How exactly do you fix this?
Look at your import statements at the top. If you are saying import android.R, then there that is a problem. It might not be the only one as these 'R' errors can be tricky, but it would definitely definitely at least part of the problem.
If that doesn't fix it, make sure your eclipse plugin(ADT) and your android SDK are fully up to date, remove the project from the emulator/phone by manually deleting it from the OS, and clean the project (Launch Eclipse->Project->Clean...). Sounds silly to make sure your stuff is fully up to date, but the earlier versions of the ADT and SDK has a lot of annoying bugs related to the R files that have since been cleared up.
Just FYI, the stuff that shows up in the R class is generated from the stuff in your project res (aka resources) folder. The R class allows you to reference a resource (such as an image or a string) without having to do file operations all over the place. It does other stuff too, but that's for another answer. Android OS uses a similar scheme - it has a resources folder and the class android.R is the way to access stuff in the android resources folder. The problem arises when in a single class you are using both your own resources, and standard android resources. Normally you can say import at the top, and then reference a class just using the last bit of the name (for example, import java.util.List allows you to just write List in your class and the compiler knows you mean java.util.List). When you need to use two classes that are named the same thing, as is the case with the auto-generated R class, then you can import one of them and you have to fully qualify the other one whenever you want to mean it. Typically I import the R file for my project, and then just say android.R.whatever when I want an android resource.
Also, to reiterate Andy, don't modify the R file automatically. That's not how it's meant to be used.
Do not modify the R class. The error means there's something syntactically wrong with your XML layouts and R cannot be auto-generated. Try looking there and post the xml code you're not sure about, if any.
Edit : also: remove "import android.R" from imports at top of file (if there)
One possible solution:-
Summary: make sure you are using import com.yourpkgdomainname.yourpkgappname.R instead of import android.R
Details: The problem occured when I changed ID of a label which was being referred in other places in the layout XML file. Due to this error, the R file stopped generating at first. Eclipse is bad in handling errors with the layout files.
When I corrected the ID reference (with project clean few times and Eclipse restarts, I noticed that my import packages now has:
import android.R
Changing it to following fixed the error:
import com.example.app.R
I just fixed my problem right-clicking in the layout folder and clicking in the option Validate. Some windows will appear, you just clik OK and ist fine.
May be you created a new xml file in Layout Directory that file name containing a Capital Letter which is not allowed in xml file under Layout Directory.
Hope this help.
Just throwing this out there, but try retyping things manually. There's a chance that your quotation marks are the "wrong" ones as there's a similar unicode character which looks similar but is NOT a quotation mark.
If you copy/pasted the code snippits off a website, that might be your problem.
As Jake has mentioned, the problem might be because of copy/paste code.
Check the main.xml under res/layout. If there is no id field in that then you have a problem.
A typical example would be as below
<com.androidplot.xy.XYPlot
android:id="#+id/mySimpleXYPlot"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="10px"
android:layout_marginLeft="20px"
android:layout_marginRight="20px"
title="A Simple Example"
/>
Some times eclipse may confuse with other projects in the same directory.
Just change package name (don't forget to change in Android manifest file also), ensure the package name is not used already in the directory. It may work.
Just came across this myself.
Finally found my issue was with a .png file that I added that had a capital letter in it an caused exactly the same problem. Eclipse never flagged the file until I closed it and opened Eclipse back up.
What seems to be the problem, I just fixed mine in case anyone was wondering - Due to other errors i turned off build automatically, when i created a new project it said R.layout.main had an issue and needed to import R; So naturally as a novice, i did. Then i built manually and it had a problem with main. Try building your program as is, remove import R and it should be fine.
In main.xml (or wherever your item is defined) make sure that the ID for the R item is defined with #+id/... Here is an example with a button:
<Button android:text="B1" android:id="#+id/button_one"
android:layout_gravity="center_horizontal|center"
android:layout_height="fill_parent" android:layout_width="wrap_content" />
Each of these is important because:
# must precede the string
+ indicates it will create if not existing (whatever your item is)
I also had this error when I was working in a Java class once. My problem was simply that my xml file, with the references in it, was not saved. If you have both the xml file and java class open in tabs, check to make sure the xml file name in the tab doesn't have a * by it.
Hope this helps.
Just Clean your project so R will be generated automatically. This worked for me.
It gave me enough pain but I found the solution:
PROJECT ---> Clean ----> (Sele)
I had this problem but in my case it solved by restarting the eclipse.
For me the cause of the problem was that I had 2 images with the same name in my drawable-hdpi folder. Once I resolved that, then the R.java rebuilt itself and the problem was automatically solved.
select Project tab and click Build automatically so Build all option will be activated and then click on build all.and always start xml file name with lowercase.