我在擴展的asynctask中出現此錯誤,但我確定Object []是一個Void []。在AsyncTask中無法將對象[]轉換爲Void []
這是我的自定義的AsyncTask:
public abstract class RepeatableAsyncTask<A, B, C> extends AsyncTask<A, B, C> {
private static final String TAG = "RepeatableAsyncTask";
public static final int DEFAULT_MAX_RETRY = 5;
private int mMaxRetries = DEFAULT_MAX_RETRY;
private Exception mException = null;
/**
* Default constructor
*/
public RepeatableAsyncTask() {
super();
}
/**
* Constructs an AsyncTask that will repeate itself for max Retries
* @param retries Max Retries.
*/
public RepeatableAsyncTask(int retries) {
super();
mMaxRetries = retries;
}
/**
* Will be repeated for max retries while the result is null or an exception is thrown.
* @param inputs Same as AsyncTask's
* @return Same as AsyncTask's
*/
protected abstract C repeatInBackground(A...inputs);
@Override
protected final C doInBackground(A...inputs) {
int tries = 0;
C result = null;
/* This is the main loop, repeatInBackground will be repeated until result will not be null */
while(tries++ < mMaxRetries && result == null) {
try {
result = repeatInBackground(inputs);
} catch (Exception exception) {
/* You might want to log the exception everytime, do it here. */
mException = exception;
}
}
return result;
}
/**
* Like onPostExecute but will return an eventual Exception
* @param c Result same as AsyncTask
* @param exception Exception thrown in the loop, even if the result is not null.
*/
protected abstract void onPostExecute(C c, Exception exception);
@Override
protected final void onPostExecute(C c) {
super.onPostExecute(c);
onPostExecute(c, mException);
}
這是給人的問題子類:
public class ListPalinasAsynkTask extends RepeatableAsyncTask<Void, Void, List<Palina>>{
private static final String TAG = "ListPalinasAsynkTask";
private static final boolean D = SystemConstants.ACTIVE_DEBUG;
private ApiRequest.ListPalinasCallback mCallback;
public ListPalinasAsynkTask(ApiRequest.ListPalinasCallback callback) {
if(D) Log.d(TAG, "Called: ListPalinasAsynkTask([callback])");
mCallback = callback;
}
@Override
protected List<Palina> repeatInBackground(Void... voids) {
/* Here i send request to get palinas */
return Api.getPalinasNearMe();
}
@Override
protected void onPostExecute(List<Palina> palinas, Exception exception) {
if(exception != null)
Logging.e(TAG, "Received exception in Asynk Task", exception);
if(palinas != null)
mCallback.result(palinas);
else
mCallback.result(new ArrayList<Palina>());
}
}
最後,這是錯誤:
E/ListPalinasAsynkTask﹕ Received exception in Asynk Task
java.lang.ClassCastException: java.lang.Object[] cannot be cast to java.lang.Void[]
at ListPalinasAsynkTask.repeatInBackground(ListPalinasAsynkTask.java:19)
at RepeatableAsyncTask.doInBackground(RepeatableAsyncTask.java:43)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
我可以解釋這個例外,因爲我給Void作爲參數!這不應該是一個對象。 你有解決方案嗎?
編輯: ListPalinasAsyncTask.java:19是指:
public class ListPalinasAsynkTask extends RepeatableAsyncTask<Void, Void, List<Palina>> {
RepeatableAsyncTask.java:43:
result = repeatInBackground(inputs);
編輯2:
我打電話以這種方式執行:
AsyncTask mAsyncTask = new ListPalinasAsynkTask(callback);
....
mAsyncTask.execute();
完美的解決方案。方法調用'super.execute()'是這裏的重要部分。 – Mulgard
你的解釋不正確。正確的一個在這裏http://stackoverflow.com/a/34400140/5455629 – q126y
同樣適用於super.executeOnExecutor(...) - 如果您重寫AsyncTask –