[英]Custom Implementation of Callback for Retrofit in Kotlin
我最近开始使用Kotlin进行android开发,并且遇到了一些小问题,这些问题可以通过使用文档来解决,但是使用Retrofit Callback实现时,我遇到了问题。 我在Java中使用了Retrofit回调的自定义实现:
public abstract class RemoteCallback<T> implements Callback<T> {
@Override
public final void onResponse(Call<T> call, Response<T> response) {
switch (response.code()) {
case HttpsURLConnection.HTTP_OK:
case HttpsURLConnection.HTTP_CREATED:
case HttpsURLConnection.HTTP_ACCEPTED:
case HttpsURLConnection.HTTP_NOT_AUTHORITATIVE:
if (response.body() != null) {
onSuccess(response.body());
}
break;
case HttpURLConnection.HTTP_UNAUTHORIZED:
onUnauthorized();
break;
default:
onFailed(new Throwable("Default " + response.code() + " " + response.message()));
}
}
@Override
public final void onFailure(Call<T> call, Throwable t) {
onFailed(t);
}
public abstract void onSuccess(T responseBody);
public abstract void onUnauthorized();
public abstract void onFailed(Throwable throwable);}
我在Kotlin Project中使用了相同的类,该类将Java代码转换为Kotlin代码
abstract class RemoteCallback<T> : Callback<T> {
override fun onResponse(call: Call<T>, response: Response<T>) {
when (response.code()) {
HttpsURLConnection.HTTP_OK,
HttpsURLConnection.HTTP_CREATED,
HttpsURLConnection.HTTP_ACCEPTED,
HttpsURLConnection.HTTP_NOT_AUTHORITATIVE ->
if (response.body() != null)
onSuccess(response.body())
HttpURLConnection.HTTP_UNAUTHORIZED -> onUnauthorized()
else -> onFailed(Throwable("Default " + response.code() + " " + response.message()))
}
}
override fun onFailure(call: Call<T>, t: Throwable) {
onFailed(t)
}
abstract fun onSuccess(responseBody: T)
abstract fun onUnauthorized()
abstract fun onFailed(throwable: Throwable)}
问题是当我调用onSucess(response.body())时,它说“不可能强制转换为'T',因为'response.body()'是一个复杂的表达式” 请指导我如何解决它
您正在将Nullable
值作为参数发送给NonNull
函数。 因此,您遇到了这个问题。 您可以像这样:
interface RemoteCallback<T> : Callback<T> {
override fun onResponse(call: Call<T>?, response: Response<T>?) {
when (response?.code()) {
HttpsURLConnection.HTTP_OK,
HttpsURLConnection.HTTP_CREATED,
HttpsURLConnection.HTTP_ACCEPTED,
HttpsURLConnection.HTTP_NOT_AUTHORITATIVE ->
response.body()?.apply { onSuccess(this) }
HttpURLConnection.HTTP_UNAUTHORIZED -> onUnauthorized()
else -> onFailed(Throwable("Default " + response?.code() + " " + response?.message()))
}
}
override fun onFailure(call: Call<T>?, t: Throwable?) {
// handle error mechanism
t?.apply { onFailed(this) }
}
fun onSuccess(responseBody: T)
fun onUnauthorized()
fun onFailed(throwable: Throwable)
}
或者,您可以只使用onSuccess(responseBody: T?)
,您的代码应该可以工作
我的项目有一个非常相似的实现。 尝试按照
abstract class RemoteCallback: Callback<ResponseBody> {
override fun onFailure(call: Call<ResponseBody>?, t: Throwable?) {
onFailed(t)
}
override fun onResponse(call: Call<ResponseBody>?, response: Response<ResponseBody>?) {
when (response.code()) {
HttpsURLConnection.HTTP_OK,
HttpsURLConnection.HTTP_CREATED,
HttpsURLConnection.HTTP_ACCEPTED,
HttpsURLConnection.HTTP_NOT_AUTHORITATIVE ->
if (response.body() != null)
onSuccess(response.body())
HttpURLConnection.HTTP_UNAUTHORIZED -> onUnauthorized()
else -> onFailed(Throwable("Default " + response.code() + " " + response.message()))
}
}
abstract fun onUnauthorized()
abstract fun onFailed(throwable: Throwable)
}
对我来说很好
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