R cannot be resolved to a variable - My First App

Question

I created a android app with eclipse but when I try to execute I've this problem.

package com.example.myfirstapp;

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.main, menu);
        return true;
    }

}

In the instruction where I use "R" like : setContentView(R.layout.activity_main); builder tell me an error and exactly "R cannot be resolved to a variable"

I've read something about this but I haven't found my solution. It's like R is android.R and not my layout folder. I don't know what to do! I need a little hint. This is really my first android App.

http://stackoverflow.com/questions/885009/r-cannot-be-resolved-android-error?rq=1 — Kirit Vaghela, Jun 29 '13 at 13:33
Please refer http://stackoverflow.com/questions/885009/r-cannot-be-resolved-android-error?rq=1 — , Jun 29 '13 at 13:33
Usually Resource file isn't automatically generated if there are errors in your .xml files so, do a double check in your `res/layout/activity_main.xml` layout :) — Cob013, Jun 29 '13 at 13:35
If you click on it, it will give a few default solutions, in your case maybe importing com.example.myfirstapp.R would work. — Mdlc, Jun 29 '13 at 14:15

score 1 · Answer 1 · answered Jun 29 '13 at 13:34

1

If you have android.R in the import lines, delete it. Then, to import the appropiate class:

Ctrl + Shift + o (Windows)
Cmd + Shift + o (Mac)

If you get a window due to a conflict, choose the R class of your project.

answered Jun 29 '13 at 13:34

Dhanesh Budhrani

190
3
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score 0 · Answer 2 · answered Jun 29 '13 at 13:34

0

Have you tried doing Project-> Clean? That might fix your problem

answered Jun 29 '13 at 13:34

Emmanuel

13,083
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Lion · Answer 3 · 2013-06-29T17:35:54.393

0

Make sure that the res/ directory doesn't have any compilation errors, which will prevent the IDE from producing a valid R.java file, which is used to resolve the R symbol.

edited Jun 29 '13 at 17:35

answered Jun 29 '13 at 13:39

Lion

965
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score 0 · Answer 4 · answered Jun 29 '13 at 17:45

best way to resolve this problem, you should use small alpha-bate latter and underscore when you give the file name in drawable folder , res folder , or when paste the image in drawable folder always the name of the images only in small latter . Then clean the project .

score 0 · Answer 5 · answered Aug 15 '13 at 18:47

0

I literally tried everything but nothing worked until I went to Window/Android SDK Manager and I installed the SDK Build tools. I then cleaned my app, waited few seconds and the errors disappeared.

answered Aug 15 '13 at 18:47

Maher Manoubi

585
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R cannot be resolved to a variable - My First App

5 Answers5