How do I set the selected state of an image button with xml

Question

I have an image button as defined below.

<ImageButton 
    android:text="Play"
    android:src="@drawable/playpause"
    android:background="@drawable/opaque" 
    android:gravity="center_horizontal"
    android:id="@+id/player_ctrl_btn"
    android:layout_width="fill_parent" 
    android:padding="0px"
    android:layout_height="wrap_content" />

I want to set the default state of the button to be selected. So in code I would say:

playBtn.setSelected(true);

Is it possible to do this in xml?

Answer 1

It doesn't look like you can -- sorry!

Answer 2

A newer solution to the problem would be to use DataBinding.

1. Create a @BindingAdapter (somewhere in your code):

@BindingAdapter("is_selected")
fun setSelected(view: View, selected: Boolean) {
    view.isSelected = selected
}

2. Use DataBinding in your xml

<layout xmlns:android="http://schemas.android.com/apk/res/android">

    <data>
    </data>

    <ImageButton
        android:id="@+id/player_ctrl_btn"
        is_selected="@{true}"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/opaque"
        android:gravity="center_horizontal"
        android:padding="0px"
        android:src="@drawable/playpause"
        android:text="Play" />
</layout>

---

IMPORTANT: remember that you need to use DataBinding here. So you cannot simply call add is_selected="true" (because it will fail not telling you about it), you need to add is_selected="@{true}"