Use data binding to set View visibility
AndroidAndroid DatabindingAndroid Problem Overview
Trying to set visibility of View
using custom variable, but error occurs: Identifiers must have user defined types from the XML file. visible is missing it
. Is it possible to set view visibility using data binding? Thanks.
<data>
<variable
name="sale"
type="java.lang.Boolean"/>
</data>
<FrameLayout android:visibility="@{sale ? visible : gone}"/>
Android Solutions
Solution 1 - Android
As stated in the Android Developer Guide, you need to do it like this:
<data>
<import type="android.view.View"/>
<variable
name="sale"
type="java.lang.Boolean"/>
</data>
<FrameLayout android:visibility="@{sale ? View.GONE : View.VISIBLE}"/>
Solution 2 - Android
In your layout:
<data>
<variable
name="viewModel"
type="...."/>
</data>
<View
android:layout_width="10dp"
android:layout_height="10dp"
android:visibility="@{viewModel.saleVisibility, default=gone}"/>
In your ViewModel java code:
@Bindable
public int getSaleVisibility(){
return mSaleIndecator ? VISIBLE : GONE;
}
Solution 3 - Android
The problem is that visibility
is an Integer
on the View
class, this means you have two ways to make this work:
- Use the
View.VISIBLE
andView.GONE
constants. https://developer.android.com/topic/libraries/data-binding/index.html#imports - Define a custom setter for
visibility
that takes aBoolean
. https://developer.android.com/topic/libraries/data-binding/index.html#custom_setters
Possible implementation:
@BindingAdapter("android:visibility")
public static void setVisibility(View view, Boolean value) {
view.setVisibility(value ? View.VISIBLE : View.GONE);
}
Which will make <FrameLayout android:visibility="@{sale}"/>
work.
Solution 4 - Android
Similar to Kiskae solution. Put this method in a separate file, for instance, Bindings.kt:
@BindingAdapter("android:visibility")
fun View.bindVisibility(visible: Boolean?) {
isVisible = visible == true
// visibility = if (visible == true) View.VISIBLE else View.GONE
}
Then in layout XML:
<data>
<variable
name="viewModel"
type="SomeViewModel" />
</data>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="@{viewModel.number == 1}" />