Search code examples
javaandroidxmldom4j

dom4j attributeValue with qualified name


I'm using dom4j to parse AndroidManifestFile.xml. However I found that it treats "android:xxx" attribute strangely.

For example:

    <receiver android:name="ProcessOutgoingCallTest" android:exported="false"                                                                                                              
        android:enabled="false">                                                                                                                                                           
        <intent-filter android:priority="1">                                                                                                                                               
            <action android:name="android.intent.action.NEW_OUTGOING_CALL" />                                                                                                              
            <category android:name="android.intent.category.DEFAULT" />                                                                                                                    
        </intent-filter>                                                                                                                                                                   
    </receiver>

The return value e.attributeValue("android:exported") will be null however using e.attributeValue("exported") will obtain the correct string (but I don't like this way since it may match more than expected). Meanwhile, e.attributeValue(new QName("android:exported")) will still be a null string.

What's the correct way to get the attribute


Solution

  • The android: is nothing more than a namespace in XML.

    If there is only one possible namespace, it is ok to write e.attributeValue("exported").

    QName represents a qualified name value of an XML element or attribute. It consists of a local name and a Namespace instance

    QName(String name)       
    QName(String name, Namespace namespace)    
    QName(String name, Namespace namespace, String qualifiedName) 
    

    thus, new QName("android:exported") is wrong, and the correct form is

    new QName("exported", new Namespace("android", "http://schemas.android.com/apk/res/android"))
    

    If you miss its namespace here, you take it as NO_NAMESPACE for default.

    public QName(String name) {
        this(name, Namespace.NO_NAMESPACE);
    }
    

    Example:

            Element root = document.getRootElement();
            Namespace namespace = new Namespace("android", "http://schemas.android.com/apk/res/android");
            for(Iterator i = root.elementIterator("receiver"); i.hasNext();)
            {
                Element e = (Element)i.next();
                System.out.println(e.attributeValue("exported"));
                System.out.println(e.attributeValue(new QName("exported", namespace)));
            }