XML attributes from merge layout to RelativeLayout

Question

According to this CommonsWare example I managed to get my RelativeLayout subclass to be merged with my layout described in a xml layout with merge root. My only concern is that I cannot describe my RelativeLayout parameters in xml.

My xml layout:

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:my="http://schemas.android.com/apk/res/hu.someproject"
  android:layout_width="36dp"
  android:layout_height="wrap_content"
  android:layout_marginLeft="3dp"
  android:layout_marginRight="3dp"
  android:width="36dp" >

 <RelativeLayout
    android:id="@+id/upper_container"
    style="?pretty_style"
    android:layout_alignLeft="@+id/image_title"
    android:layout_alignParentTop="true"
    android:layout_alignRight="@+id/image_title"
    android:layout_centerHorizontal="true" >

    <View
        android:id="@+id/upper_indicator"
        android:layout_width="fill_parent"
        android:layout_height="5dp"
        android:layout_alignParentTop="true"
        android:background="@color/mycolor" />

    <TextView
        android:id="@+id/text_degree"
        style="?pretty_style"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="23°" />
</RelativeLayout>

<hu.MyView
    android:id="@+id/image_title"
    style="?my_image_title"
    android:layout_below="@+id/upper_container"
    android:layout_centerHorizontal="true"
    my:myColor="#2f8741"/>

I think the problem is that merge happens to the children of the merge tag, and not the merge itself. Any idea how can I get my parameters in the merge to affect my RelativeLayout?

My RelativeLayout subclass, without package declaration and imports:

public class MyRelativeLayoutSubclass extends RelativeLayout {

    public MyRelativeLayoutSubclass(Context context) {
        super(context);

        initTile(null);
    }

    public MyRelativeLayoutSubclass(Context context, AttributeSet attrs) {
        super(context, attrs);

        initTile(attrs);
    }

    public MyRelativeLayoutSubclass(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initTile(attrs);
    }

    private void initTile(Object object) {
        final LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.my_great_little_layout, this, true);
    }
}

I know I can add everything to a LayoutParams, and then add my MyRelativeLayoutSubclass with that LayoutParams, but I would like escape that, that's a lot of unnecessary code.

Answer 1

Extracting all the attributes into Style was a solution for me. As a bonus it's screen-size dependent unlike the hard-coded attributes or Java-code. Maybe you can go further and put it into the Theme attributes.

<com.example.widget.MyCustomView
    android:id="@+id/my_custom_view"

    style="@style/MyCustomView.Default"/>

Answer 2

I think the problem is that merge happens to the children of the merge tag, and not the merge itself.

AFAIK, you are correct. <merge> is a placeholder, not a ViewGroup.

I know I can add everything to a LayoutParams, and then add my MyRelativeLayoutSubclass with that LayoutParams, but I would like escape that, that's a lot of unnecessary code.

Create an XML layout file containing a MyRelativeLayoutSubclass element, and put your attributes there. Then, inflate that layout.