Sure, the above example is meaningless, but it demonstrates how to use this type of expression chaining. It also works with any attribute that has a data binding expression: This works when referencing two-way bindable attributes. In the above layout, the TextView showing the user’s first name will be visible only when the showName CheckBox is checked. Now you can also access View attributes from your expressions, just like properties in your data model: Otherwise, two-way data binding would be supported on nearly every attribute as we could add notifications for the missing attributes. Remember, Android Data Binding is designed to work for all versions back to API 7, so it doesn’t rely on any new framework changes. Fortunately, this includes pretty much all the ones you really care about for user input. Two-way binding doesn’t work for every attribute - only the ones that have event notifications for changes. I also removed the ID because it wasn’t needed anymore. Since the model is updated as the user types, I no longer need to actively retrieve the name from the EditText. Instead of attempting this, you can use the two-way binding operator to automatically update the view model with the user’s changes: Or maybe you would get extra fancy and strap on an afterTextChanged listener to update your model. Normally, you’d let the user type in the data and then submit the form. Let’s imagine we have a form for the user to fill out that includes an EditText for the user’s first name. Android Studio 2.1 introduced two-way binding to make this much easier. We often want a very simple thing: get the data that the user enters back into the application model. So far, I’ve shown how to use Android Data Binding to put information from your application into the UI and bind UI events to your application. Get That User Input Back Into The Application
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