我正在尝试解析JSON 数据到List中，我想实现这个目标： -
Category List -> Sub-Category List
我的 JSON 看起来像这样：
[
{
"categoryName" : "Killer",
"categoryList" : [{"ProductID": "1",
"ProductName": "Jeans"},
{"ProductID": "2",
"ProductName": "Tees"}]
},
{
"categoryName" : "Blackberry",
"categoryList" : [{"ProductID": "1",
"ProductName": "Trousers"},
{"ProductID": "2",
"ProductName": "Shirts"}]
}
]
通过使用以下代码，我可以获取类别列表， CategoryActivity.java ：
public class CategoryActivity extends ListActivity {
// Connection detector
ConnectionDetector cd;
// Alert dialog manager
AlertDialogManager alert = new AlertDialogManager();
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jsonParser = new JSONParser();
ArrayList<HashMap<String, String>> categoriesList;
// albums JSONArray
JSONArray categories = null;
// albums JSON url
static final String URL_CATEGORIES = "http://domain.it/keyurls/multi.json";
// ALL JSON node names
private static final String CATEGORY_NAME = "categoryName";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_category);
cd = new ConnectionDetector(getApplicationContext());
// Check for internet connection
if (!cd.isConnectingToInternet()) {
// Internet Connection is not present
alert.showAlertDialog(CategoryActivity.this, "Internet Connection Error",
"Please connect to working Internet connection", false);
// stop executing code by return
return;
}
// Hashmap for ListView
categoriesList = new ArrayList<HashMap<String, String>>();
// Loading Albums JSON in Background Thread
new LoadAlbums().execute();
// get listview
ListView lv = getListView();
/**
* Listview item click listener
* TrackListActivity will be lauched by passing album id
* */
lv.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View view, int arg2,
long arg3) {
// on selecting a single album
// TrackListActivity will be launched to show tracks inside the album
Intent i = new Intent(getApplicationContext(), ProductActivity.class);
// send album id to tracklist activity to get list of songs under that album
String category_name = ((TextView) view.findViewById(R.id.category_name)).getText().toString();
i.putExtra("category_name", category_name);
startActivity(i);
}
});
}
/**
* Background Async Task to Load all Albums by making http request
* */
class LoadAlbums extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(CategoryActivity.this);
pDialog.setMessage("Listing Categories ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting Categories JSON
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
String json = jsonParser.makeHttpRequest(URL_CATEGORIES, "GET",
params);
// Check your log cat for JSON reponse
Log.d("Categories JSON: ", "> " + json);
try {
categories = new JSONArray(json);
if (categories != null) {
// looping through All albums
for (int i = 0; i < categories.length(); i++) {
JSONObject c = categories.getJSONObject(i);
// Storing each json item values in variable
String name = c.getString(CATEGORY_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(CATEGORY_NAME, name);
// adding HashList to ArrayList
categoriesList.add(map);
}
}else{
Log.d("Categories: ", "null");
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all albums
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
CategoryActivity.this, categoriesList,
R.layout.list_item_category, new String[] { CATEGORY_NAME }, new int[] {
R.id.category_name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
但每当我点击任何类别项目时，获取空白活动代替显示产品列表，请参阅我的代码 ProductActivity.java ：
public class ProductActivity extends ListActivity {
// Connection detector
ConnectionDetector cd;
// Alert dialog manager
AlertDialogManager alert = new AlertDialogManager();
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jsonParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
// products JSONArray
JSONArray products = null;
// Category name
String category_name;
private static final String CATEGORY_NAME = "categoryName";
private static final String CATEGORY_LIST = "categoryList";
private static final String PRODUCT_ID = "ProductID";
private static final String PRODUCT_NAME = "ProductName";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_product);
cd = new ConnectionDetector(getApplicationContext());
// Check if Internet present
if (!cd.isConnectingToInternet()) {
// Internet Connection is not present
alert.showAlertDialog(ProductActivity.this, "Internet Connection Error",
"Please connect to working Internet connection", false);
// stop executing code by return
return;
}
// Get album id
Intent i = getIntent();
category_name = i.getStringExtra("category_name");
// Hashmap for ListView
productsList = new ArrayList<HashMap<String, String>>();
// get listview
ListView lv = getListView();
/**
* Listview on item click listener
* SingleTrackActivity will be lauched by passing album id, song id
* */
lv.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View view, int arg2,
long arg3) {
}
});
}
/**
* Background Async Task to Load all tracks under one album
* */
class LoadTracks extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(ProductActivity.this);
pDialog.setMessage("Loading products ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting products json and parsing
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// post category name as GET parameter
params.add(new BasicNameValuePair(CATEGORY_NAME, category_name));
// getting JSON string from URL
String json = jsonParser.makeHttpRequest(CategoryActivity.URL_CATEGORIES, "GET",
params);
// Check your log cat for JSON reponse
Log.d("Product List JSON: ", json);
try {
JSONObject jObj = new JSONObject(json);
if (jObj != null) {
category_name = jObj.getString(CATEGORY_NAME);
products = jObj.getJSONArray(CATEGORY_LIST);
if (products != null) {
// looping through All songs
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String song_id = c.getString(PRODUCT_ID);
String name = c.getString(PRODUCT_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put("category_name", category_name);
map.put(PRODUCT_ID, song_id);
map.put(PRODUCT_NAME, name);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
Log.d("Categories: ", "null");
}
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all tracks
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
ProductActivity.this, productsList,
R.layout.list_item_product, new String[] { "category_name", PRODUCT_ID, PRODUCT_NAME},
new int[] {
R.id.album_id, R.id.song_id, R.id.album_name });
// updating listview
setListAdapter(adapter);
}
});
}
}
所以我的问题是如何解析二级列表的数据以及我在哪里做错了？
我也无法理解 Logcat 的内容，请参阅以下内容： -
11-11 23:26:40.501: I/Choreographer(520): Skipped 54 frames! The application may be doing too much work on its main thread.
11-11 23:26:41.681: D/Categories JSON:(921): > [
11-11 23:26:41.681: D/Categories JSON:(921): {
11-11 23:26:41.681: D/Categories JSON:(921): "categoryName" : "Killer",
11-11 23:26:41.681: D/Categories JSON:(921): "categoryList" : [{"ProductID": "1",
11-11 23:26:41.681: D/Categories JSON:(921): "ProductName": "Jeans"},
11-11 23:26:41.681: D/Categories JSON:(921): {"ProductID": "2",
11-11 23:26:41.681: D/Categories JSON:(921): "ProductName": "Tees"}]
11-11 23:26:41.681: D/Categories JSON:(921): },
11-11 23:26:41.681: D/Categories JSON:(921): {
11-11 23:26:41.681: D/Categories JSON:(921): "categoryName" : "Blackberry",
11-11 23:26:41.681: D/Categories JSON:(921): "categoryList" : [{"ProductID": "1",
11-11 23:26:41.681: D/Categories JSON:(921): "ProductName": "Trousers"},
11-11 23:26:41.681: D/Categories JSON:(921): {"ProductID": "2",
11-11 23:26:41.681: D/Categories JSON:(921): "ProductName": "Shirts"}]
11-11 23:26:41.681: D/Categories JSON:(921): }
11-11 23:26:41.681: D/Categories JSON:(921): ]
11-11 23:26:42.281: I/Choreographer(921): Skipped 35 frames! The application may be doing too much work on its main thread.
11-11 23:26:42.281: I/Choreographer(288): Skipped 30 frames! The application may be doing too much work on its main thread.
11-11 23:27:40.051: I/ActivityManager(288): START u0 {cmp=com.example.androidhive/com.example.json.ProductActivity (has extras)} from pid 921
11-11 23:27:40.071: W/WindowManager(288): Screenshot failure taking screenshot for (164x291) to layer 21010
11-11 23:27:40.092: E/SoundPool(288): error loading /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.092: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.092: E/SoundPool(288): error loading /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.102: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.102: E/SoundPool(288): error loading /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.102: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.102: E/SoundPool(288): error loading /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.102: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.111: E/SoundPool(288): error loading /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.111: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
11-11 23:27:40.111: E/SoundPool(288): error loading /system/media/audio/ui/KeypressStandard.ogg
11-11 23:27:40.122: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/KeypressStandard.ogg
11-11 23:27:40.122: E/SoundPool(288): error loading /system/media/audio/ui/KeypressSpacebar.ogg
11-11 23:27:40.122: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/KeypressSpacebar.ogg
11-11 23:27:40.122: E/SoundPool(288): error loading /system/media/audio/ui/KeypressDelete.ogg
11-11 23:27:40.122: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/KeypressDelete.ogg
11-11 23:27:40.131: E/SoundPool(288): error loading /system/media/audio/ui/KeypressReturn.ogg
11-11 23:27:40.131: W/AudioService(288): Soundpool could not load file: /system/media/audio/ui/KeypressReturn.ogg
11-11 23:27:40.131: W/AudioService(288): onLoadSoundEffects(), Error -1 while loading samples
11-11 23:27:40.462: V/PhoneStatusBar(393): setLightsOn(true)
11-11 23:27:40.741: I/ActivityManager(288): Displayed com.example.androidhive/com.example.json.ProductActivity: +585ms
11-11 23:39:00.151: D/dalvikvm(288): GC_FOR_ALLOC freed 637K, 61% free 5193K/13268K, paused 90ms, total 105ms
答案 0 :(得分：0)
// You need to add this in for loop of urs
JSONArray list = new JSONArray = c.getString(CATEGORY_NAME);
for (int j = 0; j < list.length(); j++) {
// again parse it
}
答案 1 :(得分：0)
public class AndroidJSONParsingActivity extends ListActivity {
// url to make request
private static String url = "http://10.0.2.2/product.php";
private static final String TAG_PRODUCTS = " ";
private static final String TAG_ID = "Id";
private static final String TAG_PID = "productId";
private static final String TAG_QTY = "productQty";
private static final String TAG_PRICE = "productPrice";
// contacts JSONArray
JSONArray products = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Contacts
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_ID);
String pid = c.getString(TAG_PID);
String qty = c.getString(TAG_QTY);
String price = c.getString(TAG_PRICE);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_ID, id);
map.put(TAG_PID, pid);
map.put(TAG_QTY, qty);
// adding HashList to ArrayList
contactList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(this, contactList,
R.layout.list_item,
new String[] { TAG_PID, TAG_QTY, TAG_PRICE }, new int[] {
R.id.name, R.id.email, R.id.mobile });
setListAdapter(adapter);
// selecting single ListView item
ListView lv = getListView();
// Launching new screen on Selecting Single ListItem
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.name))
.getText().toString();
String cost = ((TextView) view.findViewById(R.id.email))
.getText().toString();
String description = ((TextView) view.findViewById(R.id.mobile))
.getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),
SingleMenuItemActivity.class);
in.putExtra(TAG_PID, name);
in.putExtra(TAG_QTY, cost);
in.putExtra(TAG_PRICE, description);
startActivity(in);
}
});
}
}
这可能对你有用..
答案 2 :(得分：0)
问题出在您的lv.setOnItemClickListener
将其更改为
lv.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View view, int arg2,
long arg3) {
// on selecting a single album
// TrackListActivity will be launched to show tracks inside the album
HashMap<String, String> o=(HashMap<String,String>)lv.getItemAtPosition(Position);
Intent i = new Intent(getApplicationContext(), ProductActivity.class);
i.putExtra("category_name", o.get(category_name));
startActivity(i);
}
});
希望这会有所帮助.. !!
答案 3 :(得分：0)
试试这个
JSONArray arr;
try {
arr = new JSONArray("YOUR_JSON");
for (int i = 0; i < arr.length(); i++) {
JSONObject catList = arr.getJSONObject(i);
String catName = catList.getString("categoryName");
System.out.println("categoryName:" + catName);
JSONArray list = catList.getJSONArray("categoryList");
for (int j = 0; j < list.length(); j++) {
JSONObject subCatList = list.getJSONObject(i);
String productID = subCatList.getString("ProductID");
String productName = subCatList.getString("ProductName");
System.out.println("Sub CatList" + productID + " "
+ productName);
}
}
} catch (J
SONException e) {
e.printStackTrace();
}