cannot resolve symbol R?

Question

I'm new to android and saw other people having the same question but the solutions didn't work.

i tried multiple times to clean, sync and build the project after changes but every time is says that it can't resolve R

adding:
import nl.test123.R;
didn't work because than the next error popsup:
Error:attribute 'nl.test123.soundboard:layout_background' not found.

also this didn't work

import android.R

this is the code:"MainActivity.java"

package nl.test123.testsoundboard;

import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
//import nl.test123.R;

public class MainActivity extends AppCompatActivity {
    MediaPlayer mysound1;
    MediaPlayer mysound2;
    MediaPlayer mysound3;

    private TextView mTextMessage;

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.navigation_top:
//                    mTextMessage.setText(R.string.title_top);
                    return true;
                case R.id.navigation_latest:
//                    mTextMessage.setText(R.string.title_latest);
                    return true;
                case R.id.navigation_favorite:
//                    mTextMessage.setText(R.string.title_favorite);
                    return true;
            }
            return false;
        }
    };

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

        mTextMessage = (TextView) findViewById(R.id.message);
        BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);


        mysound1 = MediaPlayer.create(this, R.raw.bird);
        mysound2 = MediaPlayer.create(this, R.raw.bomb);
        mysound3 = MediaPlayer.create(this, R.raw.dog);
    }

    public void sound1(View view){
        mysound1.start();
    }
    public void sound2(View view){
        mysound2.start();
    }
    public void sound3(View view){
        mysound3.start();
    }
}

can anyone see what i'm doing wrong or forgetting to do.

see the xml below:"activity_main.xml"

 <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="nl.marvinboontjes.cucumbersoundboard.MainActivity">

    <TextView
        android:id="@+id/message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="92dp"
        android:layout_marginTop="128dp"
        android:text="@string/title_home"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent" />


    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_blue_light"
        android:onClick="Sound1"
        android:text="Bird"
        tools:layout_editor_absoluteX="16dp"
        tools:layout_editor_absoluteY="16dp"
        tools:ignore="MissingConstraints" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="sound2"
        android:text="Bomb"
        tools:layout_editor_absoluteX="147dp"
        tools:layout_editor_absoluteY="16dp"
        tools:ignore="MissingConstraints"  />

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onclick="sound3"
        android:text="Dog"
        tools:layout_editor_absoluteX="269dp"
        tools:layout_editor_absoluteY="16dp"
        tools:ignore="MissingConstraints" />

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="?android:attr/windowBackground"
        app:layout_background="@color/colorPrimary"
        app:itemIconTint="@drawable/nav_item_color_state"
        app:itemTextColor="@drawable/nav_item_color_state"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/navigation" />

</android.support.constraint.ConstraintLayout>

Error images: picture1 picture2

like a said, i tried the solutions in the other questions but they don't work — Fcmarv, Jan 08 '18 at 10:41
solution `android:onClick="Sound1"` should be `android:onClick="sound1"` — Fcmarv, Jan 08 '18 at 12:26

score 0 · Accepted Answer · answered Jan 08 '18 at 08:42

0

use yourpackagename.R.

in your case it will be nl.test123.testsoundboard.R

I think you have an error in your layout. BottomNavigationView doesn't have app:layout_background attribute. remove it and rebuild again.

answered Jan 08 '18 at 08:42

coder

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removed this line: `app:layout_background="@color/colorPrimary"` but still get the error. – Fcmarv Jan 08 '18 at 09:48
@Fcmarv please put new error message received, after removing that line. – coder Jan 08 '18 at 10:09
still the same "cannot resolve symbol R" – Fcmarv Jan 08 '18 at 10:40
i removed the line android:onClick="Sound1" on the buttons and the errors are gone? – Fcmarv Jan 08 '18 at 11:15

cannot resolve symbol R?

1 Answers1