Jetpack Compose已经出现Beta版本好久了，尝试了一下，总的感觉和Flutter、SwiftUI葫芦画瓢的。同样的响应式、快速搭建UI界面，同时，jetpack compose结合Kotlin的语言特性，必定能给安卓的原生开发重新树立新的标杆。
好了，下面来说说Jetpack Compose的网络请求。废话不多说，上正题：
1.使用框架: Retrofit2
在app的build.gradle内添加如下：
dependencies {
implementation 'com.squareup.retrofit2:retrofit:2.4.0'
implementation 'com.squareup.retrofit2:converter-gson:2.1.0'
}
2.封装Network，代码如下
interface RequestService {
@GET("elephants")
fun listRepos(): Call<List<Feed>>
@POST(value = "api-admin/login")
fun logIn(
@Query("username") username: String,
@Query("password") password: String
): Call<LogInBackData>
}
class Network {
companion object {
//创建拦截器
private val interceptor = Interceptor { chain ->
val request = chain.request()
val requestBuilder = request.newBuilder()
val url = request.url()
val builder = url.newBuilder()
requestBuilder.url(builder.build())
.method(request.method(), request.body())
.addHeader("clientType", "IOS")
.addHeader("Content-Type", "application/x-www-form-urlencoded")
chain.proceed(requestBuilder.build())
}
//创建OKhttp
private val client: OkHttpClient.Builder = OkHttpClient.Builder()
.addInterceptor(interceptor)
.connectTimeout(10, TimeUnit.SECONDS)
.readTimeout(20, TimeUnit.SECONDS)
.retryOnConnectionFailure(false)
private var retrofit: Retrofit = Retrofit.Builder()
.baseUrl("你的baseUrl")
.addConverterFactory(GsonConverterFactory.create())
.client(client.build())
.build()
var service: RequestService = retrofit.create(RequestService::class.java)
}
可以实现请求头的配置、超时时间的配置、以及包括了简单的Get请求和Post请求的案例，用接口进行封装。
3.封装ViewModel类进行对对应接口的调用，代码如下：
class ViewMod : ViewModel() {
private var _todoItems = MutableLiveData(listOf<Feed>())
val todoItems: LiveData<List<Feed>> = _todoItems
private var _todoItems1 = MutableLiveData(listOf<LogInBackData>())
val todoItems1: LiveData<List<LogInBackData>> = _todoItems1
fun getList() {
Network.service.listRepos().enqueue(object : Callback<List<Feed>> {
override fun onResponse(call: Call<List<Feed>>, response: Response<List<Feed>>) {
response.body()?.let { it ->
_todoItems.value = it.toMutableList()
}
}
override fun onFailure(call: Call<List<Feed>>, t: Throwable) {
t.printStackTrace()
println("request wrong")
}
})
}
fun getLog() {
Network.service.logIn(username = "13964299760", password = "z2399395")
.enqueue(object : Callback<LogInBackData> {
override fun onResponse(
call: Call<LogInBackData>,
response: Response<LogInBackData>
) {
response.body()?.let { it ->
_todoItems1.value = mutableListOf(it)
println("logloglog${it}")
}
}
override fun onFailure(call: Call<LogInBackData>, t: Throwable) {
t.printStackTrace()
println("request wrong1：$t")
}
})
}
}
结合liveData进行实现。
4.模型创建，用数据类进行创建，如下：
data class LogInBackData(
val msg: String,
val code: Int,
val data: Map<String, Any>
)
5.在Activity里面调用，代码如下：
@Composable
fun CreateItems(viewModel: ViewMod) {
val mList by viewModel.todoItems.observeAsState()
viewModel.getList()
LazyColumn {
itemsIndexed(items = mList!!) { index, item: Feed ->
println("网络数据是:${mList}")
SingleItem(item = item, onClick = {
})
}
}
}
其中的ViewMode是上面定义的继承自ViewModel的实例，结合LiveData的observeAsState保证了数据的刷新。
