如何通过Android布局xml中的数据绑定更改背景？

Question

I want to use the folloeing code to change the background of ConstraintLayout.

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

    <data>
        <import type="android.view.View"/>
        <import type="com.example.test.R" />
        <variable
            name="viewModel"
            type="com.example.test.viewModel.MainViewModel"/>

    </data>

    <android.support.constraint.ConstraintLayout
        android:id="@+id/layoutOtpRoot"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:animateLayoutChanges="true"
        android:background="@{viewModel.isCheck() ? @android:color/pinkColor : @android:drawable/bg}">

    </android.support.constraint.ConstraintLayout>
</layout>

But it is not working , the background did not show anything , I also try the folloeing...and it still not working

android:background="@{viewModel.isCheck() ? color.pinkColor : R.drawable.bg}"

I am sure the viewModel.isCheck() is working , but the background did not show anything.

Did I missing something ? Thanks in advance.

Answer 1

大概吧 。

  android:background="@{viewModel.isCheck() ? @color/pinkColor : @drawable/bg}"

Answer 2

I think you can add backgroud in the layout!

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