我正在将JSON数据解析为ListView，并在MainActivity.java中成功解析了第一级JSON，其中我显示了主要位置列表，如：
内部地点
外部地点
现在我希望每当我点击内部位置然后在SecondActivity中它应该在列表中显示德里和NCR，同样适用于外部位置，在这种情况下，每当用户点击需要显示美国
JSON看起来像：
{
"all": [
{
"title": "Inner Locations",
"maps": [
{
"title": "Delhi",
"markers": [
{
"name": "Connaught Place",
"latitude": 28.632777800000000000,
"longitude": 77.219722199999980000
},
{
"name": "Lajpat Nagar",
"latitude": 28.565617900000000000,
"longitude": 77.243389100000060000
}
]
},
{
"title": "NCR",
"markers": [
{
"name": "Gurgaon",
"latitude": 28.440658300000000000,
"longitude": 76.987347699999990000
},
{
"name": "Noida",
"latitude": 28.570000000000000000,
"longitude": 77.319999999999940000
}
]
}
]
},
{
"title": "Outer Locations",
"maps": [
{
"title": "United States",
"markers": [
{
"name": "Virgin Islands",
"latitude": 18.335765000000000000,
"longitude": -64.896335000000020000
},
{
"name": "Vegas",
"latitude": 36.114646000000000000,
"longitude": -115.172816000000010000
}
]
}
]
}
]
}
注意：但是每当我在第一个活动中点击任何ListItem时，没有在SecondActivity中获取任何列表，为什么？
MainActivity.java： -
@Override
protected Void doInBackground(Void... params) {
// Create an array
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions
.getJSONfromURL("http://10.0.2.2/locations.json");
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("all");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrieve JSON Objects
map.put("title", jsonobject.getString("title"));
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void args) {
// Locate the listview in listview_main.xml
listview = (ListView) findViewById(R.id.listview);
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(MainActivity.this, arraylist);
// Set the adapter to the ListView
listview.setAdapter(adapter);
// Close the progressdialog
mProgressDialog.dismiss();
listview.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(MainActivity.this, String.valueOf(position), Toast.LENGTH_LONG).show();
// TODO Auto-generated method stub
Intent sendtosecond = new Intent(MainActivity.this, SecondActivity.class);
// Pass all data rank
sendtosecond.putExtra("title", arraylist.get(position).get(MainActivity.TITLE));
Log.d("Tapped Item::", arraylist.get(position).get(MainActivity.TITLE));
startActivity(sendtosecond);
}
});
}
}
}
SecondActivity.java：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the view from listview_main.xml
setContentView(R.layout.listview_main);
Intent in = getIntent();
strReceived = in.getStringExtra("title");
Log.d("Received Data::", strReceived);
// Execute DownloadJSON AsyncTask
new DownloadJSON().execute();
}
// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... params) {
// Create an array
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions
.getJSONfromURL("http://10.0.2.2/locations.json");
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("maps");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrieve JSON Objects
map.put("title", jsonobject.getString("title"));
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
答案 0 :(得分：2)
尝试以下方法： -
try
{
JSONObject j = new JSONObject("your json response");
JSONArray all = j.getJSONArray("all");
for (int i = 0; i < all.length(); i++)
{
JSONObject data = all.getJSONObject(i);
System.out.println("title =>"+data.getString("title"));
JSONArray maps = data.getJSONArray("maps");
for (int k = 0; k < maps.length(); k++)
{
JSONObject data_sec = maps.getJSONObject(k);
System.out.println("name => "+data_sec.getString("name"));
System.out.println("latitude => "+data_sec.getString("latitude"));
System.out.println("longitude => "+data_sec.getString("longitude"));
}
}
}
catch (Exception e)
{
// TODO: handle exception
}
答案 1 :(得分：0)
// Try this way,hope this will help you to solve your problem.
@Override
protected Void doInBackground(Void... params) {
// Create an array
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions
.getJSONfromURL("http://10.0.2.2/locations.json");
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("all");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrieve JSON Objects
map.put("title", jsonobject.getString("title"));
map.put("index", i);
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void args) {
// Locate the listview in listview_main.xml
listview = (ListView) findViewById(R.id.listview);
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(MainActivity.this, arraylist);
// Set the adapter to the ListView
listview.setAdapter(adapter);
// Close the progressdialog
mProgressDialog.dismiss();
listview.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(MainActivity.this, String.valueOf(position), Toast.LENGTH_LONG).show();
// TODO Auto-generated method stub
Intent sendtosecond = new Intent(MainActivity.this, SecondActivity.class);
// Pass all data rank
sendtosecond.putExtra("title", arraylist.get(position).get(MainActivity.TITLE));
sendtosecond.putExtra("index", arraylist.get(position).get(MainActivity.INDEX));
Log.d("Tapped Item::", arraylist.get(position).get(MainActivity.TITLE));
Log.d("Tapped Item Index::", arraylist.get(position).get(MainActivity.INDEX));
startActivity(sendtosecond);
}
});
}
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the view from listview_main.xml
setContentView(R.layout.listview_main);
Intent in = getIntent();
strReceived = in.getStringExtra("title");
strReceivedIndex = in.getStringExtra("index");
Log.d("Received Data::", strReceived);
// Execute DownloadJSON AsyncTask
new DownloadJSON().execute();
}
// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... params) {
// Create an array
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions
.getJSONfromURL("http://10.0.2.2/locations.json");
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("all").getJSONObject(Integer.parseInt(strReceivedIndex)).getgetJSONArray("maps");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrieve JSON Objects
map.put("title", jsonobject.getString("title"));
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}