無法覆蓋doInBackground方法（asyncTask）

Question

為什么我不能在課堂上重寫doInBackground方法？

public class AttemptLogin extends AsyncTask {


@Override

protected void onPreExecute() {

    super.onPreExecute();

}

@Override

protected JSONObject doInBackground(String... args) {



    String email = args[2];
    String password = args[1];
    String name= args[0];

    ArrayList params = new ArrayList();
    params.add(new BasicNameValuePair("username", name));
    params.add(new BasicNameValuePair("password", password));
    if(email.length()>0)
        params.add(new BasicNameValuePair("email",email));

    JSONObject json = jsonParser.makeHttpRequest(URL, "POST", params);


    return json;

}

protected void onPostExecute(JSONObject result) {

    // dismiss the dialog once product deleted
    //Toast.makeText(getApplicationContext(),result,Toast.LENGTH_LONG).show();

    try {
        if (result != null) {
            Toast.makeText(getApplicationContext(),result.getString("message"),Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(getApplicationContext(), "Unable to retrieve any data from server", Toast.LENGTH_LONG).show();
        }
    } catch (JSONException e) {
        e.printStackTrace();
    }


}

}

錯誤：必須將類AttemptLogin聲明為抽象或在'AsyncTask'中實現抽象方法'doInBackground（Params ...）

如果將doInBackground的參數更改為（Object []），它將起作用。 為什么我不能傳遞字符串值？

Answer 1

public class AttemptLogin extends AsyncTask<String, Void, JSONObject> {...}

Answer 2

將您的代碼更改為這樣

public class AttemptLogin extends AsyncTask<String,Void,JSONObject> {
...

您必須告訴AsyncTask您返回類型的類，否則默認為object