android数据绑定在自定义控件 [英] android databinding in custom controls

问题描述

在官方android文档中 - 有一些指导如何在片段和活动中使用数据绑定。不过我有很多复杂的选择器，具有很高的设置。类似于：

In official android docs - there is some guidance how to use databinding in fragments and activities. However I have pretty complex picker with high ammount of settings. Something like:

class ComplexCustomPicker extends RelativeLayout{
    PickerViewModel model;
}

所以我的问题是我需要覆盖的方法是什么在其中使用绑定，而不是设置/检查诸如textfield等的单个值？

So my question is what method of the picker I need to override to be able use binding inside it and not seting/checking individual values like textfield, etc?

第二个问题 - 我如何将viewmodel传递给xml文件中的选择器，我需要一些自定义属性吗？

And second question - how could I pass viewmodel to my picker in xml file, do I need some custom attributes for that?

推荐答案

我认为使用自定义设置器可以解决您的问题。 查看本节的开发人员指南。

I think using Custom Setters will solve your problem. Check this section in developers guidelines.

我可以给你一个简单的例子。假设您的视图名称为 CustomView ，并且您的viewmodel为 ViewModel ，则在任何类中，创建一个方法如下：

I can give you a brief example for it. Suppose the name of your view is CustomView and of your viewmodel is ViewModel, then in any of your class, create a method like this:

@BindingAdapter({"bind:viewmodel"})
public static void bindCustomView(CustomView view, ViewModel model) {
    // Do whatever you want with your view and your model
}

在您的布局中，执行以下操作：

And in your layout, do the following:

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

    <data>

        <variable
            name="viewModel"
            type="com.pkgname.ViewModel"/>
    </data>

    // Your layout

    <com.pkgname.CustomView 
    // Other attributes
    app:viewmodel="@{viewModel}"
    />

</layout>

从您的活动使用此设置ViewModel：

And from your Activity use this to set the ViewModel:

MainActivityBinding binding = DataBindingUtil.setContentView(this, R.layout.main_activity);
ViewModel viewModel = new ViewModel();
binding.setViewModel(viewModel);

或者您可以直接从自定义视图中膨胀：

Or you can directly inflate from your custom view:

LayoutViewCustomBinding binding = DataBindingUtil.inflate(LayoutInflater.from(getContext()), R.layout.layout_view_custom, this, true);
ViewModel viewModel = new ViewModel();
binding.setViewModel(viewModel);

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