Question

请帮助我，如果响应代码是204如何调用，应该再次致电服务器？

String command = ("http://api.railwayapi.com/live/train/" + m_train_Number + "/doj/" + m_year + m_month + m_day + "/apikey/tc9sc898/");
new JSONTask().execute(command);

public class JSONTask extends AsyncTask<String, String, LiveStationModel>
{
    LiveStationModel liveStationModel = null;
    protected LiveStationModel doInBackground(String... params) {
        IOException e;
        MalformedURLException e2;
        List<LiveStationModel> myList = null;
        Throwable th;
        JSONException e3;
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try {
            connection = (HttpURLConnection) new URL(params[0]).openConnection();
            connection.connect();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            try {
                StringBuffer buffer = new StringBuffer();
                String str = "";
                while (true) {
                    str = bufferedReader.readLine();
                    if (str == null) {
                        break;
                    }
                    buffer.append(str);
                }

Answer 1

你可以检查它是onPostExecute方法，如：

@Override
protected void onPostExecute(Void aVoid) {
     super.onPostExecute(aVoid);
     //check your if condition here
}

Answer 2

   public class JSONTask extends AsyncTask<String, String, LiveStationModel>
    {
    int resp;

                -------
                connection.connect();
                resp = connection.getResponseCode();
                --------
                    }

现在覆盖onPostExecute，就像这样，

@Override
protected void onPostExecute(Void aVoid) {
     super.onPostExecute(aVoid);
     if(resp == 204)
{
     new JSONTask().execute(command);
}
else
{
//your code here
}
}

Answer 3

在AsyncTask的onPostExecute方法中使用if条件。

Answer 4

在你的onPostExecute方法中检查你是否得到了预期的结果，如果不是再次调用你的新JSONTask（）。执行（命令）;

喜欢

@Override
protected void onPostExecute(Void aVoid) {
     super.onPostExecute(aVoid);
   new JSONTask().execute(command);
}

Answer 5

这将检查响应是否为204但是如果您想尝试另一个连接，disconnect当前连接，然后使用不同的URL建立另一个连接;因为如果你重复你的网址，你会一次又一次地得到相同的结果（NO_CONTENT）。

public class JSONTask extends AsyncTask<String, String, LiveStationModel>
{
    LiveStationModel liveStationModel = null;
    protected LiveStationModel doInBackground(String... params) {
        IOException e;
        MalformedURLException e2;
        List<LiveStationModel> myList = null;
        Throwable th;
        JSONException e3;
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try {
            connection = (HttpURLConnection) new URL(params[0]).openConnection();
            connection.connect();

            if(connection.getResponseCode() == HttpURLConnection.HTTP_NO_CONTENT)
            {
                //do what you gonna do
            }

如果你想重复，直到你得到内容使用这样的循环：

    try {

        int code = connection.getResponseCode();
        while(code == 204)
        {

            connection = (HttpURLConnection) new URL(params[?]).openConnection();   // Different Parameter here
            connection.connect();

            ....

        }

如何在异步任务中调用if语句？

5 个答案: