Kotlin + Retrofit + RxJava简单封装使用详解

本文介绍了Kotlin + Retrofit + RxJava简单封装使用详解，分享给大家，具体如下：

实例化Retrofit

object RetrofitUtil {
val CONNECT_TIME_OUT = 30//连接超时时长x秒
val READ_TIME_OUT = 30//读数据超时时长x秒
val WRITE_TIME_OUT = 30//写数据接超时时长x秒
val retrofit: Retrofit by lazy {
Log.d("RetrofitUtil", "retrofit init lazy")
Retrofit.Builder()
.baseUrl("http://gank.io/api/")  //本文以GitHub API为例
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.client(getOkHttpClient())
.build()
}
private fun getOkHttpClient(): OkHttpClient {
val builder = OkHttpClient.Builder()
builder.connectTimeout(CONNECT_TIME_OUT.toLong(), TimeUnit.SECONDS)
.writeTimeout(WRITE_TIME_OUT.toLong(), TimeUnit.SECONDS)
.readTimeout(READ_TIME_OUT.toLong(), TimeUnit.SECONDS)
if (BuildConfig.DEBUG) {
builder.addInterceptor(HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.BODY))
} else {
builder.addInterceptor(HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.NONE))
}
// 设置请求头
builder.addInterceptor { chain ->
val time = (System.currentTimeMillis() / 1000).toString() + ""
val requestBuilder = chain.request().newBuilder()
requestBuilder.addHeader("time", time)
chain.proceed(requestBuilder.build())
}
return builder.build()
}
}

返回数据封装

class Response<T> {
var error: Boolean = false
var results: T? = null
}

demo中用了gank.io的开发api，之前一般项目的返回格式是code + message + T的格式。

api接口错误/异常统一处理类

class ApiException : Exception {
var code: Int = 0//错误码
var msg: String? = null//错误信息
constructor(throwable: Throwable, code: Int) : super(throwable) {
this.code = code
}
constructor(code: Int, msg: String) {
this.code = code
this.msg = msg
}
}

定义ExceptionFunction处理onErrorResumeNext：

class ExceptionFunction<T> : Function<Throwable, Observable<T>> {
override fun apply(@NonNull throwable: Throwable): Observable<T> {
Log.e("ExceptionFunction", throwable.message)
return Observable.error(ExceptionEngine().handleException(throwable))
}
}
/**
* 错误/异常处理工具
*/
class ExceptionEngine {
val UN_KNOWN_ERROR = 1000//未知错误
val ANALYTIC_SERVER_DATA_ERROR = 1001//解析(服务器)数据错误
val CONNECT_ERROR = 1002//网络连接错误
val TIME_OUT_ERROR = 1003//网络连接超时
fun handleException(e: Throwable): ApiException {
val ex: ApiException
if (e is ApiException) {  //服务器返回的错误
return e
} else if (e is HttpException) {       //HTTP错误
ex = ApiException(e, e.code())
ex.msg = "网络错误:" + ex.code
return ex
} else if (e is JsonParseException
|| e is JSONException
|| e is ParseException || e is MalformedJsonException) { //解析数据错误
ex = ApiException(e, ANALYTIC_SERVER_DATA_ERROR)
ex.msg = "解析错误"
return ex
} else if (e is ConnectException) {//连接网络错误
ex = ApiException(e, CONNECT_ERROR)
ex.msg = "连接失败"
return ex
} else if (e is SocketTimeoutException) {//网络超时
ex = ApiException(e, TIME_OUT_ERROR)
ex.msg = "网络超时"
return ex
} else { //未知错误
ex = ApiException(e, UN_KNOWN_ERROR)
ex.msg = e.message
return ex
}
}
}

封装请求处理

object Rx {
/**
* Rxlifecycle绑定生命周期
*/
fun <T, E> get(observable: Observable<Response<T>>, lifecycleProvider: LifecycleProvider<E>): Observable<T> {
// 请求绑定生命周期，防止内存泄漏，同时返回回调之后页面已销毁造成的空指针错误
if (lifecycleProvider is RxAppCompatActivity) {
val rxAppCompatActivity = lifecycleProvider as RxAppCompatActivity
observable.compose(rxAppCompatActivity.bindUntilEvent(ActivityEvent.DESTROY))
} else if (lifecycleProvider is RxFragment) {
val rxFragment = lifecycleProvider as RxFragment
observable.compose(rxFragment.bindUntilEvent(FragmentEvent.DESTROY))
}
return observable
.compose(HandleResult())
.onErrorResumeNext(ExceptionFunction())
}
/**
* 部分后台请求
*/
fun <T> get(observable: Observable<Response<T>>): Observable<T> {
return observable
.compose(HandleResult())
.onErrorResumeNext(ExceptionFunction())
}
private class HandleResult<T> : ObservableTransformer<Response<T>, T> {
override fun apply(upstream: Observable<Response<T>>): ObservableSource<T> {
return upstream.flatMap { response -> createResult(response) }
.subscribeOn(Schedulers.io())
.unsubscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
}
}
private fun <T> createResult(response: Response<T>): Observable<T> {
return Observable.create({ subscriber ->
if (response.error)
throw ApiException(-1, "服务器异常") // 一般来说，自己的服务器异常会返回相应的code和message
else
response.results?.let {
subscriber.onNext(response.results!!)
} ?: subscriber.onComplete()
})
}
}

定义HttpObserver统一处理返回

abstract class HttpObserver<T> : Observer<T> {
/**
* 标记是否为特殊情况
*/
private var resultNull: Boolean = true
override fun onComplete() {
// 特殊情况：当请求成功，但T == null时会跳过onNext，仍需当成功处理
if (resultNull)
onSuccess(null)
}
override fun onSubscribe(d: Disposable) {
// 可在此处加上dialog
}
override fun onError(e: Throwable) {
if (e is ApiException) {
onError(e.code, e.msg)
} else {
onError(0, e.message)
}
}
override fun onNext(t: T) {
resultNull = false
onSuccess(t)
}
abstract fun onSuccess(t: T?)
/**
* 统一处理失败，比如登录失效等
*
* @param code
* @param msg
*/
open fun onError(code: Int, msg: String?) {
}
}

Api

class Result {
var _id: String? = null
var createdAt: String? = null
var desc: String? = null
var publishedAt: String? = null
var source: String? = null
var type: String? = null
var url: String = ""
var isUsed: Boolean = false
var who: String? = null
var images: List<String>? = null
/**
* 妹子小图
*/
fun meiziSmallUrl(): String {
val meizi = url
return meizi.replace("large", "small")
}
}
interface Apiservice {
@GET("data/{type}/10/{page}")
fun getGank(@Path("type") type: String, @Path("page") page: Int): Observable<Response<List<Result>>>
}
object Api {
val apiservice: Apiservice by lazy {
Log.d("Api", "apiservice create lazy")
RetrofitUtil.retrofit.create(Apiservice::class.java)
}
}

使用

override fun loadData() {
Rx.get(Api.apiservice.getGank(getType(), mIntPage), this).subscribe(object : HttpObserver<List<Result>>() {
override fun onSuccess(t: List<Result>?) {
//getDataSuccess(t)
}
override fun onError(code: Int, msg: String?) {
super.onError(code, msg)
//getDataFailed()
}
})
}

使用了Rxlifecycle绑定生命周期来处理可能发生的内存泄漏问题，Fragment跟Activity需要继承Rx相应的基类。

练手项目

Meizikt Gank.io Android客户端，使用Kotlin + Retrofit2 + RxJava

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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