Error parsing XML: duplicate attributes?

Question

I'm having trouble setting the background for my button. I tried setting it to

android:background="@drawable/mybutton_background" 

but that caused an error, saying "String types not allowed" referring to "@drawable/mybutton_background". It also caused another error causing me to lose my R.java file and giving me the "R cannot be resolved into a variable error". I just gave up on the button and deleted the background, but the error remained after it was deleted. Well, that error is now gone and I now get a message that says Error parsing XML: duplicate attributes for one line of code, but once I delete that line, the error message moves on to another line! It's like Eclipse won't update to realize I deleted that line of code. I checked for updates and cleaned my project countless times, but I'm still getting the same error. Does anyone know what's up with my project?

My error log:

activity_main.xml: Paint.setShadowLayer is not supported.
activity_main.xml: Failed to convert @drawable/ into a drawable
activity_main.xml: Failed to convert android:background=" into a drawable

activity_main:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="android:background=&quot;"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentLeft="true"
        android:scaleType="fitCenter"
        android:src="@drawable/ball01" />

    <Button
        android:background="@drawable/"
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/imageView1"
        android:layout_alignLeft="@+id/imageView1"
        android:layout_marginBottom="17dp"
        android:background="@drawable/mybutton_background"  <----- where I get the error
        android:focusableInTouchMode="true"
        android:text="Enlighten me!"
        android:textColor="#3f0f7f"
        android:textSize="32sp"
        android:textStyle="bold|italic"
        android:typeface="serif"
        android:visibility="visible" />

    <LinearLayout
        android:layout_width="match_parent"0        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:weightSum="1" >

        <View
            android:id="@+id/view1"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_weight="0.2" />

        <TextView
            android:id="@+id/textView1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.6"
            android:gravity="center_horizontal"
            android:shadowColor="@android:color/white"
            android:shadowRadius="10"
            android:textSize="32sp" />

        <View
            android:id="@+id/view2"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_weight="0.2" />

    </LinearLayout>

</RelativeLayout>

MainActivity.java:

package com.example.crystalball;

import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {


    private CrystalBall mCrystalBall = new CrystalBall();
    private TextView mAnswerLabel;
    private Button mGetAnswerButton;
    private ImageView mCrystallBallImage;

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

        mAnswerLabel = (TextView) findViewById(R.id.textView1);
        mGetAnswerButton = (Button) findViewById(R.id.button1);
        mCrystallBallImage = (ImageView) findViewById(R.id.imageView1);

        mGetAnswerButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                String answer = mCrystalBall.getAnAnswer();

                mAnswerLabel.setText(answer);

                animateCrystalBall();
                animateAnswer();
            }
        });
    }

    public void animateCrystalBall() {
        mCrystallBallImage.setImageResource(R.drawable.ball_animation);
        AnimationDrawable ballAnimation = (AnimationDrawable) mCrystallBallImage.getDrawable();
        if (ballAnimation.isRunning()) {
            ballAnimation.stop();
        }
        ballAnimation.start();
    }

    private void animateAnswer() {
        AlphaAnimation fadeInAnimation = new AlphaAnimation(0, 1);
        fadeInAnimation.setDuration(1500);
        fadeInAnimation.setFillAfter(true);

        mAnswerLabel.setAnimation(fadeInAnimation);
    }

    @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;
    }

}

Thanks for anything you can contribute!

Answer 1

In my case this error was due to duplicate xmlns attributes inside layout. If you have something like this:

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

    <data>
        <variable
            name="person"
            type="com.abc.PersonEntity" />
    </data>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
...

Remove the xmlns attribute from the second layout:

    <LinearLayout 
...