java - Android 数组列表添加值后返回 Null

Question

我正在尝试将值添加到数组列表中，以便在 mpandroid 图表中绘制 xAxis 值，但在调试数组列表时返回 Null

在 forloop 中添加时，它显示值，但在 forloop 数组列表结束后为空帮助我

代码

private ArrayList<String> getXAxisValues() {
final ArrayList<String> xAxis = new ArrayList<>();
final Intent intent = getIntent();
final String getUserId =  intent.getStringExtra("UserId");
new Thread(new Runnable() {
    public void run() {
        HttpRequest req = null;
        try {
            req = new HttpRequest("http://abc.sc.in/abc.php");
            final String response = req.preparePost().withData("answerUserId="+getUserId).sendAndReadString();


            JSONArray myObjects = null;
            try {
                myObjects = new JSONArray(response);

                for (int ji = 1; ji < myObjects.length(); ji++) {
                    JSONObject jsonobject = myObjects.getJSONObject(ji);
                    final String Date = jsonobject.getString("date(answerDate)");
                    System.out.println("Date Response =====>: " + Date);
                   // The Values of Date (2 Dates [21,23]) here are shown while adding
                    xAxis.add(Date); 

                }

            } catch (JSONException e) {
                e.printStackTrace();
            }






        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}).start();


System.out.println("Here It shows [] after adding values ==============================>" + xAxis);

return xAxis;

}

Answer 1

创建将返回arraylist的AsynchTask任务喜欢

public class DemoAsynch extends AsyncTask<Context, Integer, ArrayList<String>>{

}

之后

ArrayList<String> abc = new DemoAsynch().execute().get();

在 abc 中，您将获得所有列表，并将您的 id 传递给该异步所需的任何内容