我无法弄清楚如何从一个每2-3秒更新一次的json api在android中获得实时更新。我已经设法下载JSON代码,然后创建一些数组并记录它们,但是我每隔2-3秒就会更改json api的值,并且我不知道如何重新下载JSON。在此先感谢您的帮助!Android JSON实时更新
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DownloadTask task = new DownloadTask();
String result = null;
try{
result = task.execute("thelinkIuse").get();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
public class DownloadTask extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection urlConnection = null;
while (true) {
try {
url = new URL(urls[0]);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while (data != -1) {
char current = (char) data;
result += current;
data = reader.read();
}
return result;
} catch (IOException e) {
e.printStackTrace();
return "Failed";
}
}
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
try {
JSONArray arr = new JSONArray(result);
for (int i = 0; i < arr.length(); i++) {
JSONObject jsonPart = arr.getJSONObject(i);
symbols.add(jsonPart.getString("symbol"));
bids.add(jsonPart.getString("bid"));
asks.add(jsonPart.getString("ask"));
}
Log.i("Symbols", String.valueOf(symbols));
Log.i("Bids", String.valueOf(bids));
Log.i("Asks", String.valueOf(asks));
} catch (JSONException e) {
e.printStackTrace();
Log.i("failed", "failed");
}
}
}
如果您觉得答案可以解决问题,请点击绿色复选标记将其标记为“已接受”。这有助于将注意力集中在仍然没有答案的旧版SO上。 –