找不到Android数据绑定属性 [英] Android data binding attribute not found

问题描述

我正在尝试复制以下答案:设置所包含布局的子元素的属性

I am trying to replicate this answer: Setting attribute of child element of included layout

我有一个简单的custom_edit_text.xml:

<?xml version="1.0" encoding="utf-8"?>
<layout
    xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable name="hint123" type="String" />
    </data>
    <android.support.design.widget.TextInputLayout
        android:id="@+id/emailInputLayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <android.support.v7.widget.AppCompatEditText
            android:id="@+id/emailField"
            android:layout_width="275dp"
            android:layout_height="wrap_content"
            android:paddingBottom="16dp"
            android:paddingTop="14dp"
            android:hint="@{hint123}"
            android:textCursorDrawable="@null"
            android:background="@drawable/edit_text_background"
            android:fontFamily="@font/eina_regular"
            android:textColor="@color/edit_text_color"
            android:textColorHint="@color/edit_text_color"
            android:textSize="15sp"
            />
    </android.support.design.widget.TextInputLayout>
</layout>

我将它包含在另一个文件中

And I include it in another file:

<?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">
    <include
            layout="@layout/custom_edit_text"
            app:hint123="Email"/>
</layout>

但是，该项目在经过清理后拒绝编译.重建并显示错误:

However the project refuses to compile after a clean & rebuild with the error:

AAPT: error: attribute hint123 (aka inc.company.appname:hint123) not found.

有什么想法吗?

我也有

dataBinding {
    enabled = true
}

已在应用级别build.gradle

推荐答案

我认为我已经找到了解决方案.要激活数据绑定，您需要使用@{}表达式，并且括号中的内容必须是有效的Java代码.因此，文字字符串必须用引号引起来......必须在XML属性值内编码为".全部放在一起，您将得到:

I think I've hit upon the solution. To activate data binding, you need to use a @{} expression, and what's in the braces must be valid Java code. So a literal string must be enclosed in quotes... which must be encoded as " inside an XML attribute value. Put it all together and you get:

<include
    layout="@layout/custom_edit_text"
    app:hint123="@{&quot;Email&quot;}"/>

数据绑定确实适用于包含文件，只是文字的语法有些复杂.我遇到了同样的问题，该表格正在我的项目中运行.

Data binding does work for include files, it's just that the syntax for a literal is a bit convoluted. I had the same issue and this form is working in my project.

这篇关于找不到Android数据绑定属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！