Android Data Binding: visibility on include tag

问题:

As per http://developer.android.com/tools/data-binding/guide.html#imports, we can have such simple expressions in visibility:

<TextView
..
android:visibility="@{user.isAdult ? View.VISIBLE : View.GONE}"/>

But when I try to do the same in an include tag, like so:

<include
android:id="@+id/image_layout"
layout="@layout/image_layout"
android:visibility="@{notification.notifType == 0 ? View.VISIBLE : View.GONE}"/>

Then Studio not only shows the expression in red, but upon building it gives the following error in the auto-generated binding class:

Error:(138, 29) error: cannot find symbol method setVisibility(int)

Here's where the error occurs in the auto-generated binding class

// batch finished
if ((dirtyFlags & 0x3L) != 0) {
    // api target 1
    this.imageLayout.setVisibility(NotifTypeNotificatio1);
}
imageLayout.executePendingBindings();

回答1:

I imagine what you are trying to do would look something like this:

In the layout you are including, specify a boolean variable and bind it to the desired view's visibility

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

    <data>

        <import type="android.view.View"/>

        <variable
            name="isVisible"
            type="boolean"/>

    </data>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="@{isVisible ? View.VISIBLE : View.GONE}"/>

</layout>

Then In your calling layout bind your value

<include
    android:id="@+id/image_layout"
    layout="@layout/image_layout"
    bind:isVisible="@{notification.notifType == 0}"/>

回答2:

You are able to pass all necessary parameters from parent xml into included xml via "http://schemas.android.com/apk/res-auto" namespace.

The syntax is res-auto namespace:variable name

For example

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <android.support.design.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <include
            layout="@layout/include_user_image"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:isVisible="@{true}" />

    </android.support.design.widget.CoordinatorLayout>
</layout>

include_user_image.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">

    <data>

        <import type="android.view.View" />

        <variable
            name="isVisible"
            type="boolean" />

    </data>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="@{isVisible ? View.VISIBLE : View.GONE}" />
</layout>

回答3:

This is a bit late, but I have run across this recently.

I believe this is actually a bug in the Data Binding compiler as it is possible to set android:visibility attribute on <include> tag directly (ie. without Databinding).

回答4:

Good explaination

1. You can directly pass Integer value of visibility like.
2. You can set default value of visibility also by setting default=gone in binding.

For example this is included_layout.xml

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

    <data>

        <variable
            name="visibility"
            type="Integer"/>

    </data>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="@{visibility, default=gone}"
        />

</layout>

and use like

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

    <data>

      <import type="android.view.View"/>

    </data>

   <include
     android:id="@+id/included_layout"
     layout="@layout/included_layout"
     app:visibility="@{View.VISIBLE}"/>

</layout>

回答5:

Try:

this.imageLayout.getRoot().setVisibility(NotifTypeNotificatio1);