XML文件错误。 Android编程

Question

I am new to android programming and recently installed Eclipse junos and ADT plugin on my ubuntu system and downloaded the android SDK. After this, i created an android project, which by default is the hello world program, when i run this program i got an error "Error in an XML file: aborting build.". But i haven't edited any code. Please help me solve this problem. Below is the program. I get an error also saying R cannot be resolved to a variable.

package com.example.myandroid;

import android.os.Bundle;

import android.app.Activity;

import android.view.Menu;

public class MainActivity extends Activity {

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

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

Here is the activity_main.xml

  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent" >
    <TextView android:layout_width="wrap_content" 
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true" 
            android:layout_centerVertical="true" 
            android:text="@string/hello_world" 
            tools:context=".MainActivity" /> 
</RelativeLayout>

Answer 1

<RelativeLayout xmlns:android="schemas.android.com/apk/res/android"; xmlns:tools="schemas.android.com/tools"; 

上面的分号似乎是问题，尝试将其删除

Answer 2

Try this

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent" >
        <TextView android:layout_width="wrap_content" 
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true" 
                android:layout_centerVertical="true" 
                android:text="@string/hello_world" 
                tools:context=".MainActivity" /> 
    </RelativeLayout>

You have extra semi colons in your xml file.

Also make sure the first line of your xml is

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

So your complete xml should look like

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
    <TextView android:layout_width="wrap_content" 
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true" 
        android:layout_centerVertical="true" 
        android:text="@string/hello_world" 
        tools:context=".MainActivity" /> 
</RelativeLayout>