Android中的怪异数据绑定 [英] Weird DataBinding in Android

问题描述

我试图弄清楚如何在Android中使用数据绑定，但遇到了一个奇怪的问题.当我将ViewModel类放在某个包中时，生成的ActivityMainBinding无法看到它并说:error: package ViewModels does not exist.但是，如果我把它放在根包中，那么麻烦就消失了.是我的错误还是某种错误?

I try to figure out how to work with data binding in Android and met a strange problem. When I put my ViewModel class in some package, generated ActivityMainBinding can't see it and say: error: package ViewModels does not exist. But if I put it in the root package, then trouble disappears. Is it my mistake or some kind of bug?

代码:

activity_main.xml

activity_main.xml

<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">

<data>
    <variable
        name="DataContext"
        type="com.example.sombrero.bluem.ViewModels.MainViewModel" />
</data>
...

MainActivity.java

MainActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
    MainViewModel mainViewModel = ViewModelProviders.of(this).get(MainViewModel.class);
    binding.setDataContext(mainViewModel);
}

MainViewModel目前只是一个空类.

MainViewModel is just empty class for now.

推荐答案

我也遇到了这个问题.感谢 tynn 回答我的

I ran into this as well. Thanks to tynn for answering my question.

根据tynn，这是因为我们没有遵循软件包的oracle命名约定.程序包名称应全部小写.将"ViewModels"更改为"viewmodels"为我修复了该问题.

According to tynn, it is because we didn't follow the oracle naming conventions for packages. The package name should be all lowercase. Changing "ViewModels" to "viewmodels" fixed it for me.

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