java - 响应监听器内部的字符串数组在监听器类外部提供空值

Question

我正在通过 JSONObject 从远程服务器获取数据。问题是，当我尝试将响应字符串保存到字符串数组中以供在响应监听器外部使用时，字符串数组会给出空值。我应该怎么做才能使我从远程服务器获得的字符串可以在响应监听器之外。

主要 Activity 。 java代码如下

   public class MainActivity extends Activity {
  MySingleton singleton;
    TextView textView;
   TextView textView2;

   Button button;
   RequestQueue rqueue;

final String url="http://www.muftiattaullahmultani.com/greeting.php";

public static int count=0;

public final String[] str=new String[2];

public String s;

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);


     textView=(TextView) findViewById(R.id.textView);
    textView2=(TextView) findViewById(R.id.textView2);
 JsonArrayRequest jsonObjectRequest= new 
     JsonArrayRequest(Request.Method.POST, url, null, new 
     Response.Listener<JSONArray>() {

public void onResponse(JSONArray response) {

    while(count<response.length())
    {
        JSONObject object= null;
        try {
            object = response.getJSONObject(count);
            String s = object.getString("id") +"  "+ object.getString("name")+"  " + object.getString("password");
            str[0]=s;
            textView.setText(str[0]);
            count++;
        } catch (JSONException e) {
            e.printStackTrace();
        }


    }

}
   }, new Response.ErrorListener() {
@Override
    public void onErrorResponse(VolleyError error) {
   textView.setText("ERROR");
  }
   });







      MySingleton.getInstance(getApplicationContext()).addToRequestQueue(jsonObjectRequest);

    textView2.setText(str[0]);

}}

TextView 1 给出了正确的值，但 textview2 给出了 NuLL 值..

Answer 1

Strong ordering that makes it easy to correctly populate your UI with data fetched asynchronously from the network.

Volley 进行异步请求，这意味着它不会阻塞主线程直到请求结束，所以 textView2.setText 将在 之前执行str 数组填充了数据。你需要把它放在 onResponse

里面