java Android：带有异步任务的 JSON 解析器（GET 和 POST 方法）
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时间：2020-10-31 06:43:08 来源:igfitidea点击:
Android : JSON Parser with async task (GET and POST methods)
提问by Twister
Just want to check whether this JSON Parser with async task is it correctly done? When I put this code into my Eclipse, this (method.equals("POST") was underline red. And it state that the 'method' cannot be solved. Any suggestion or help in this? Thank you.
只是想检查这个带有异步任务的 JSON Parser 是否正确完成？当我将此代码放入我的 Eclipse 中时，此 (method.equals("POST") 下划线为红色。它指出无法解决“方法”。对此有任何建议或帮助吗？谢谢。
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
String url=null;
List<NameValuePair> nvp=null;
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET method
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
BackGroundTask Task= new BackGroundTask(url, method, params);
try {
return Task.execute().get();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}
public class BackGroundTask extends AsyncTask<String, String, JSONObject>{
List<NameValuePair> postparams= new ArrayList<NameValuePair>();
String URL=null;
public BackGroundTask(String url, String method, List<NameValuePair> params) {
URL=url;
postparams=params;
}
@Override
protected JSONObject doInBackground(String... params) {
// TODO Auto-generated method stub
// Making HTTP request
try {
// Making HTTP request
// check for request method
if(method.equals("POST")){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(postparams));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(postparams, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
}
回答by Patryk Dobrowolski
You forgot to declare methodproperty in your BackGroundTask class.
您忘记method在 BackGroundTask 类中声明属性。
EDITLike this:
编辑像这样：
public class BackGroundTask extends AsyncTask<String, String, JSONObject>{
List<NameValuePair> postparams= new ArrayList<NameValuePair>();
String URL=null;
String method = null;
public BackGroundTask(String url, String method, List<NameValuePair> params) {
URL=url;
postparams=params;
this.method = method;
}
@Override
protected JSONObject doInBackground(String... params) {
// TODO Auto-generated method stub
// Making HTTP request
try {
// Making HTTP request
// check for request method
if(method.equals("POST")){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(postparams));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(postparams, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
}
回答by jiduvah
You need to set method as a class variable within BackGroundTask. You are passing it into the constructor but not going anything with it. Set it the same way you have done with url and postparams.
您需要在 BackGroundTask 中将方法设置为类变量。您将它传递给构造函数，但没有进行任何处理。以与 url 和 postparams 相同的方式设置它。
