无法覆盖doInBackend-method（asyncTask）

Question

为什么我不能重写类中的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();
    }


}

}

错误：类AttemptLogin必须声明为抽象或实现抽象方法'doInBackground（参数…）在“异步任务”中

如果我将doInBackground的参数更改为（Object[]），它就会工作。为什么我不能传递字符串值？

Answer 1

把你的代码改成这样

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

必须告诉AsyncTask返回类型的类，否则它默认为object

Answer 2

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