Data binding and status management manual based on the "Activity Compose" framework in the Java class library

Data binding and status management manual based on the "Activity Compose" framework in the Java class library # introduce In the Java class library, data binding and status management based on the "Activity Compose" framework are a powerful technology that can be used to simplify and accelerate the development process of Android applications.This article will introduce how to use this framework to implement data binding and status management, and provide related programming code and configuration. # 数据 数据 Data binding is a process of connecting data with user interface elements.Through data binding, when the data changes, the interface element is automatically updated, thereby synchronization of interface and data.In the "Activity Compose" framework, data binding can be implemented through the following steps: ## 1. Import Activity Compose Library First, you need to add the dependency item of the Activity Compose library to the project construction file.You can add a dealer in the dependenncies block of the build.gradle file: groovy implementation "androidx.activity:activity-compose:1.3.0-rc01" ## 2. Create a data class Next, you need to create a data class to save data that needs to be binding.For example, we create a data class called User, which contains a string attribute called name:: kotlin data class User(val name: String) ## 3. Create interface You can then use the Compose to write the interface.In the compose, you can use the@Model` annotation to declare a data class and use the `ReMember` function to create a memory state.The following is a simple example: kotlin @Model class MainActivityState(var user: User = User("John")) @Composable fun MainActivity() { val state = remember { MainActivityState() } TextField( value = state.user.name, onValueChange = { state.user = User(it) } ) } In the above example, we use the name of the `TextField` component to display and edit the user's name.The `Value` parameter of` TextField` is `state.user.name`, which means that it will display the` name` attribute of the `state.user` object, and when the user enters the data,` state.user.name` willAutomatically update. ## 4. Start Activity Finally, we need to start the Compose interface in Activity.You can create a new Activity and set the Compose interface with the `SetContent` function.The following is a simple example: kotlin class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContent { MainActivity() } } } By completing the above steps, we have implemented data binding based on the "Activity Compose" framework. # Status management In the "Activity Compose" framework, status management is a method of changing the reserved data across configuration.Through status management, data can be retained between the life cycle of Activity to avoid loss of data when configuration changes (such as screen rotation).Here are the steps to implement status management: ## 1. Use `@model` annotation In the compose interface, you can use the@Model` annotation to mark a category as a memory state.For example, in the above data binding example, we have used the `@model` annotation to mark the` MainActivityState` class. ## 2. Use the `Remember` function In the Compose interface, you can use the `Remember` function to create a memory state.For example, in the above data binding example, we used the `ReMEMBER` function to create an object of` MainActivityState. ## 3. Save and restore status When the configuration of the Activity changes, the Compose framework will automatically save and restore the state.This means that after the configuration of the screen rotation, the compose interface will continue to display the previous state. Through the above steps, we have implemented status management based on the "Activity Compose" framework. # in conclusion Data binding and status management based on the "Activity Compose" framework are a powerful technology that can be used to simplify and accelerate the development process of Android applications.Through data binding, we can easily achieve the synchronization of interface and data; through state management, we can ensure that the data is retained during configuration changes.I hope the information provided in this article is useful for developers using the "Activity Compose" framework.If you need more programming code and related configuration, please refer to the relevant official documents and example code.