对于JSON解析，哪两个更好，因为我使用了InputStreamReader，而我的JSONArray总是返回空...所以将它改为BufferedReader会有什么不同？我甚至在url中添加了API Key，它仍显示NPE ... logcat中的错误是arr.length（）用于空对象......
public class DownloadTask extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection httpURLConnection = null;
try {
url = new URL(urls[0]);
httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream in = httpURLConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while(data != -1){
char current = (char) data;
result += current;
data = reader.read();
}
return result;
}
//combined the exceptions MalformedURL and IOException to a common to display a toast msg
catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
try {
String message = "";
JSONObject jsonObject = new JSONObject(result);
String weatherInfo = jsonObject.getString("weather");
Log.i("Weather content", weatherInfo);
JSONArray arr = new JSONArray(weatherInfo);
for (int i = 0; i < arr.length(); i++) {
JSONObject jsonPart = arr.getJSONObject(i);
String main = "";
String description = "";
main = jsonPart.getString("main");
description = jsonPart.getString("description");
if (main != "" && description != "") {
message += main + ": " + description + "\r\n";
}
}
if (message != "") {
weatherReport.setText(message);
} else {
Toast.makeText(getApplicationContext(), "Could not find weather", Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
Toast.makeText(getApplicationContext(), "Could not find weather", Toast.LENGTH_LONG).show();
}
}
}