Question

当我在android排球请求的onerrorrepsonse中收到错误时，我想重试该请求。我怎样才能做到这一点？

Answer 1

好吧，您可以创建RetryPolicy来更改默认重试行为，只指定timeout milliseconds，retry count参数：

public class YourRequest extends StringRequest {
    public YourRequest(String url, Response.Listener<String> listener,
                       Response.ErrorListener errorListener) {
        super(url, listener, errorListener);
        setRetryPolicy(new DefaultRetryPolicy(DefaultRetryPolicy.DEFAULT_TIMEOUT_MS,
                DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
    }
}

另一种方法是估计VolleyError，如果是TimeoutError实例，则再次重新执行相同的请求：

public static void executeRequest() {
    RequestQueue.add(new YourRequest("http://your.url.com/", new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            if (error instanceof TimeoutError) {
                // note : may cause recursive invoke if always timeout.
                executeRequest();
            }
        }
    }));
}

你现在可能有一个问题：“让Volley提供一些重试回调方法吗？”，答案是“无”。但有一个项目调用Netroid基于Volley并满足前面的问题，有了它，如果你关心它，你可以进行重试回调，你可以计算重试到来时使用了多少时间以及这个请求执行了多长时间，代码样式如下：

final String REQUESTS_TAG = "Request-Demo";
String url = "http://facebook.com/";
JsonObjectRequest request = new JsonObjectRequest(url, null, new Listener<JSONObject>() {
    long startTimeMs;
    int retryCount;

    @Override
    public void onPreExecute() {
        startTimeMs = SystemClock.elapsedRealtime();
    }

    @Override
    public void onFinish() {
        RequestQueue.add(request);
        NetroidLog.e(REQUESTS_TAG);
    }

    @Override
    public void onRetry() {
        long executedTime = SystemClock.elapsedRealtime() - startTimeMs;
        if (++retryCount > 5 || executedTime > 30000) {
            NetroidLog.e("retryCount : " + retryCount + " executedTime : " + executedTime);
            mQueue.cancelAll(REQUESTS_TAG);
        } else {
            NetroidLog.e(REQUESTS_TAG);
        }
    }
});

request.setRetryPolicy(new DefaultRetryPolicy(5000, 20, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
request.setTag(REQUESTS_TAG);
RequestQueue.add(request);

Netroid还有许多其他方便和强大的功能，希望对你有所帮助:)。

Answer 2

您可以设置计数器变量以尝试特定时间，而不是使其完全递归

  static int count=10; //so its will try ten time
public void userLogin(final View view)
{
    final RequestQueue requestQueue= Volley.newRequestQueue(getApplicationContext());
    String url = "http://192.168.43.107/mobodb/register.php";
  StringRequest stringRequest=new StringRequest(Request.Method.POST,url,new Response.Listener<String>()
    {
        @Override
        public void onResponse(String response) {
 Toast.makeText(getApplicationContext(),"Updated",Toast.LENGTH_LONG).show();
            }
        }
    },new Response.ErrorListener()
    {
        @Override
        public void onErrorResponse(VolleyError error) {
            count=count-1;
            Toast.makeText(getApplicationContext(),"Retry left"+count,Toast.LENGTH_LONG).show();
            if (count>0) {
                // note : may cause recursive invoke if always timeout.
                userLogin(view);
            }
            else
            {
                Toast.makeText(getApplicationContext(),"Request failed pls check network connection or the error is "+error.getMessage(),Toast.LENGTH_LONG).show();
            }
        }
    })
    {
        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
           Map<String,String> paramter=new HashMap<String,String>();
        paramter.put("name",login_name);
            paramter.put("user_pass",login_pass);
            return paramter;
        }
    };
    requestQueue.add(stringRequest);
    stringRequest.setRetryPolicy(new DefaultRetryPolicy(20 * 1000, 10, 1.0f));

你也可以检查你可以从php返回的响应并处理你的java类

@Override
        public void onResponse(String response) {

            if(response.contains("no record found for"))
            Toast.makeText(getApplicationContext(),response.toString(),Toast.LENGTH_LONG).show();
            else
            {
                Toast.makeText(getApplicationContext(),"Updated num of row is"+response.toString(),Toast.LENGTH_LONG).show();
            }

        }

你的PHP代码将是

if($res){
$resp=mysql_affected_rows();
if($resp==0)
{
$resp="no record found for".$_POST['name'];
}
if($resp==1 or $resp>1)
{
$resp=mysql_affected_rows();
}else $resp="efrror is".mysql_error();

重试请求onErrorResponse Android排球

2 个答案: