Android 数据绑定 layout_width 和 layout_height [英] Android Data Binding layout_width and layout_height

问题描述

我需要能够动态设置 EditText 的高度属性.我在整个应用程序中为其他属性使用数据绑定，因此我希望能够使用数据绑定来控制元素的高度.这是我的 xml 的精简版:

I need to be able to dynamically set an EditText's height property. I am using data binding for other properties throughout my app, so I would love to be able to use data binding to control the height of my elements. Here is a stripped down version of my xml:

<?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">

<data>
    <variable name="loginVM" type="com.testing.stuff.ViewModels.LoginViewModel" />
</data>

<EditText android:inputType="number"
            android:id="@+id/txtVerificationCode"
            android:layout_height="@{loginVM.compact ? @dimen/verificationHeightCompact : @dimen/verificationHeightFull}"
            android:layout_width="match_parent"
            android:paddingRight="16dp"
            android:paddingLeft="16dp"
            android:focusable="true"
            android:focusableInTouchMode="true"
            android:layout_marginLeft="10dp"
            android:alpha="@{loginVM.verificationOpacity}"
            android:layout_marginStart="10dp"
            android:textAlignment="center"
            android:visibility="visible"
            android:hint="Enter verificationCode"
            android:text="@{loginVM.verificationCode}" />
</layout> 

这是我的视图模型的精简版:

And here is a stripped down version of my View Model:

public class LoginViewModel extends BaseObservable {
public final ObservableField<String> verificationCode; 
public final ObservableField<Boolean> compact;

@Bindable
public String getVerificationCode() {
    if (this.verificationCode == null) {
        return "";
    } else {
        return this.verificationCode.get();
    }
}

public void setVerificationCode(String verificationCode) {
    this.verificationCode.set(verificationCode);
    invalidateProperties();
}

@Bindable
public Boolean getCompact(){return this.compact.get();}

public void setCompact(Boolean value)
{
    this.compact.set(value);
    this.invalidateProperties();
}

@BindingAdapter("android:layout_height")
public static void setLayoutHeight(EditText view, float height)
{
    ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
    layoutParams.height = (int)height;
    view.setLayoutParams(layoutParams);
}

public LoginViewModel(Context ctx) {
    verificationCode = new ObservableField();
    compact = new ObservableField();
}

尺寸在 dimens.xml 文件中.我正在修改视图模型中的属性.但是，当我启动应用程序时，我在启动后立即收到以下错误(绑定适配器未在调试时触发).我在屏幕上还有其他几个元素，但这个特定的元素是我需要在发生特定操作时更改高度的元素:

The dimensions are in the dimens.xml file. And I am modifying the properties in the view model. But, when I launch the app, I'm getting the following error immediately after launch (the bindingadapter is not firing on debug). I have several other elements on the screen but this particular one is the one I need to change the height when a particular action occurs:

FATAL EXCEPTION: main

Process: com.testing.stuff, PID: 32752

java.lang.RuntimeException: Unable to start activity  
ComponentInfo{com.testing.stuff/com.testing.stuff.Login}: 
java.lang.RuntimeException: Binary XML file line #69: You must supply 
a layout_height attribute.

Caused by: java.lang.RuntimeException: Binary XML file line #69: You 
must supply a layout_height attribute.

关于此问题的 SO 上有一些帖子，但没有明确的答案或该方法不起作用.当然，这是一个常见的实现.预先感谢您的帮助.

There are a few posts on SO regarding this issue but no definitive answers or the approach did not work. Surely this is an implementation that is common. Thanks in advance for the help.

推荐答案

In Java

@BindingAdapter("layout_height")
public static void setLayoutHeight(View view, float height) {
    LayoutParams layoutParams = view.getLayoutParams();
    layoutParams.height = height;
    view.setLayoutParams(layoutParams);
}

在你的 XML 中

app:layout_height="@{ viewModel.isBig ? @dimen/dp_20 : @dimen/dp_5 }"

像这样导入应用

xmlns:app="http://schemas.android.com/apk/res-auto"

这篇关于Android 数据绑定 layout_width 和 layout_height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！