R.java file not being generated automatically

Question

I really need help out here. I am a beginner to android programming and i wanted to make a simple sudoku game. But i cant proceed further without this problem being resolved.My R.java file is not being generated.Here is the code -

package org.example.sudoku;



import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

public class Sudokugame extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sudokugame);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.sudokugame, menu);
        return true;
    }

}

it says R cannot be resolved into a variable. And R.java file is missing in the gen folder. P.S - none of my files start with a capital letter in the res folder so thats not the error.

here is my xml code:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/main_title"/>
    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/continue_label"/>
    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/new_game_label"/>
    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/about_label"/>
    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/exit_label"/>
    </LinearLayout>

and here is my strings.xml code :

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">Sudoku</string>
    <string name="main_title">Android Sudoku</string>
    <string name="continue_label">Continue</string>
    <string name="new_game_label">New Game</string>
    <string name="about_label">About</string>
    <string name="exit_label">Exit</string>

</resources>

And here is my androidmanifest.xml code :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.example.sudoku"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="1"
        android:targetSdkVersion="8" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="org.example.sudoku.Sudokugame"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Answer 1

R.java not being generated is most often due to a problem with one of the resource or manifest XML files. Review the Problems or Console windows to check/

The other issue that arises is the ADT plugin sometimes inserts extraneous "import R.java..." statements, especially after any renaming or other manipulations of package names. There usually shouldn't be any of those types of imports and they can be deleted.

After resolving any errors, and perhaps even as an extra first step, you'll want to clean and rebuild your project.z

Sometimes the error is as simple as using an invalid character in one of the resource file's name. Only the characters a-z, 0-9, underscore and period are valid. Uppercase letters and dashes are not allowed.

EDIT:

Another possibility is an outdated ADT. The ADT can get outdated whenever the SDK gets updated. Here's how to update the ADT:

In Eclipse, go to Help > Check for Updates. Then look for items with Android or ADT in the name. Select all of them and follow the wizard.

If you get "No updates were found." or don't see any relevant items in the list, then you'll have to do an install rather than an update. This page describes the installation process, but the short version is to do the following. Go to Help > Install New Software..., then click on the Add... button.

Choose and enter a name (such as "ADT") in the name field and enter "https://dl-ssl.google.com/android/eclipse/" for Location. Click on OK and select at least "Developer Tools" in the resulting list. Then click on Finish and follow the wizard.

You'll have to accept a licenses agreement and say OK for a for a validation warning.

Answer 2

Clean and followed by Build Project it will surely generated R.java file in gen foloder. if in case you have Some error in layout file (.xml) it will not generate so please make sure that check your whole project and rectify your error in both .xml and java file.

Thank you.

Answer 3

Try to Change your Manifest file.

 <uses-sdk
        android:minSdkVersion="1"
        android:targetSdkVersion="8" />

to

 <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

Once you create one activity for minsdkversion="1" it will work. But if you try to create another activity for that Project you will get the error. So make sure that you have to set at least minSdkVersion="7" then it will work.