java - 如何从异步调用返回结果

Question

我所有的异步调用都在它们自己的类中，所以我不想将全局变量设置为异步。为此，我想返回对象，例如来 self 的 asunc postProcess 方法的字符串。

这可以做到吗？

下面是我的类的一般结构，我想从 onPostExecute() 返回一个字符串。我看到其他地方提到了委托(delegate)，但这看起来很困惑，确定有一种方法可以为类或方法提供返回类型吗？

class GetStuffAsyncly extends AsyncTask<String, String, String>
{
    // my vars....

    public myconstructor(String dialogMessage, Context con)
    {
        this.qDialog =  new ProgressDialog(con);
        this.dialogString = dialogMessage;
        this.context = con;
    }

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute()
    {
        super.onPreExecute();
        do stuff like fire dialog
    }

    @Override
    protected String doInBackground(String... args)
    {
       // do stuff in background...

        return data;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    protected void onPostExecute(String jsonString)
    {
        // dismiss the dialog after getting all data
        dialog.dismiss();
    }
}

Answer 1

像下面这样的东西

class GetStuffAsyncly extends AsyncTask<String, String, String> {
    String dialogString;
    ProgressDialog dialog;
    Context context;
    AsyncListener listener;
    // my vars....

    public GetStuffAsyncly(String dialogMessage, Context con, AsyncListener listener) {
        this.dialog = new ProgressDialog(con);
        this.dialogString = dialogMessage;
        this.context = con;
        this.listener = listener;
    }

    /**
     * Before starting background thread Show Progress Dialog
     */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        listener.onTaskStarted();
    }

    @Override
    protected String doInBackground(String... args) {
        // do stuff in background...

        return data;
    }

    /**
     * After completing background task Dismiss the progress dialog
     **/
    protected void onPostExecute(String jsonString) {
        // dismiss the dialog after getting all data
        dialog.dismiss();
        listener.onTaskFinished(jsonString);
    }
}

以及监听器类

public interface AsyncListener {
    void onTaskStarted();

    void onTaskFinished(String data);
}

你可以这样调用

new GetStuffAsyncly(message, this, new AsyncListener() {
            @Override
            public void onTaskStarted() {
                //do your stuff
            }

            @Override
            public void onTaskFinished(String data) {
//Do your stuff;
            }
        }).execute(parameter);