How can I parse android activity_main.xml file and modify it?

Question

I want to parse android activity_main.xml and add custom properties tag of my views in it pragmatically.

For example: (original)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    <view
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        class="com.test.compoundviewcreation.Slider"
        android:id="@+id/view4"/>
</RelativeLayout>

After modification: (custom:sliderLabel tag added)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    <view
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        class="com.test.compoundviewcreation.Slider"
        android:id="@+id/view4"
        custom:sliderLabel="Custom SLider Label"/>
</RelativeLayout>

I tried with DOM Parser but it cant parse it and shows xml doc is null. Any idea?

Answer 1

You can try with joox library, imported using gradle like:

compile 'org.jooq:joox:1.3.0'

So then you can use find() method to get all <view> elements and attr() method to assign your custom attribute, like:

import java.io.File;
import java.io.IOException;

import org.joox.Match;
import org.xml.sax.SAXException;
import static org.joox.JOOX.$;

public class Main {

    public static void main(String[] args) throws SAXException, IOException {
        final Match $m = $(new File(args[0]));
        $m.find("view").attr("custom:sliderLabel", "Custom SLider Label");
        $m.write(System.out);
    }
}

I will assume your xml is well-formed (not like your example) and that you give the xml file as argument to the program. Also I added another <view> to show that it changes both of them.

Note that output is neither well formatted nor ordered (attributes), but that is not a xml problem. Result:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:custom="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_height="match_parent" android:layout_width="match_parent">

    <view android:id="@+id/view4" android:layout_height="wrap_content" android:layout_width="match_parent" class="com.test.compoundviewcreation.Slider" custom:sliderLabel="Custom SLider Label"/>

    <view android:id="@+id/view5" android:layout_height="wrap_content" android:layout_width="match_parent" class="com.test.compoundviewcreation.Slider" custom:sliderLabel="Custom SLider Label"/>

</RelativeLayout>

---

UPDATE : Based in comments, assuming you want to only append the new attribute to the <view> with id of view4 , you need to use namespaces. I prefer to hanlde these cases with xpath() method, like:

public static void main(String[] args) throws IOException, SAXException {
    final Match $m = $(new File(args[0]));
    $m.namespace("android", "http://schemas.android.com/apk/res/android")
            .xpath("//view[@android:id='@+id/view4']")
            .attr("custom:sliderLabel", "Custom SLider Label");
    $m.write(System.out);
}