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我目前有這個類，它解析json網址，並藉助Lazy Adapter類和後臺線程將圖像和文本加載到列表視圖中。管理Android應用程序中的後臺線程
每個列表項都包含一個圖像視圖和2個文本視圖。
我想爲每個生成的列表項創建彈出框（警報對話框）。警報對話框將具有將調用其他應用程序的選項。
我的問題：
難道是明智的，代碼在這個類此警告對話框的功能？我擔心目前有很多東西在後臺完成，可能會影響應用程序的功能。
如果沒有人可以建議另一種方式來做到這一點。謝謝。
的Json活動課：
public class JsonActivity extends SherlockActivity{
private ProgressDialog progressDialog;
// JSON Node names
static final String TAG_NAME = "name";
static final String TAG_IMAGEURL = "imageurl";
ListView list;
LazyAdapter adapter;
String chartUrl;
String[] urlNames = new String[] {
"urls..."
};
// chartItemList is the array list that holds the chart items
ArrayList<HashMap<String, String>> chartItemList = new ArrayList<HashMap<String,
String>>();
//Holds imageurls
ArrayList<String> imageurls = new ArrayList<String>();
JsonParser Parser = new JsonParser();
// JSONArray
JSONArray chartItems = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.chart);
//Get the bundle
Bundle bundle = getIntent().getExtras();
//Extract the data from the bundle
int chartIndex = bundle.getInt("chartIndex");
String chartUrl = urlNames[chartIndex];
setTitle(bundle.getString("chartname"));
//url from where the JSON has to be retrieved
String url = chartUrl;
//Check if the user has a connection
ConnectivityManager cm = (ConnectivityManager)
getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo info = cm.getActiveNetworkInfo();
if (info != null) {
if (!info.isConnected()) {
Toast.makeText(this, "Please check your connection and try again.",
Toast.LENGTH_SHORT).show();
}
//if positive, fetch the articles in background
else new getChartItems().execute(chartUrl);
}
//else show toast
else {
Toast.makeText(this, "Please check your connection and try again.",
Toast.LENGTH_SHORT).show();
}
}
class getChartItems extends AsyncTask<String, String, String> {
// Shows a progress dialog while setting up the background task
@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog = new ProgressDialog(JsonActivity.this);
progressDialog.setMessage("Loading chart...");
progressDialog.setIndeterminate(false);
progressDialog.setCancelable(false);
progressDialog.show();
}
//Gets the json data for chart items data and presents it in a list view
@Override
protected String doInBackground(String... args) {
String json = Parser.getJSONFromUrl(args[0]);
String imageurl;
String rank;
String name;
String url;
try{
chartItems = new JSONArray(json);
JSONObject json_data=null;
for(int i=0;i<chartItems.length();i++){
json_data = chartItems.getJSONObject(i);
//Retrieves the value of the name from the json object
name=json_data.getString("name");
//Retrieves the image url for that object and adds it to an arraylist
imageurl=json_data.getString("imageurl");
//imageurls.add(imageurl);
HashMap<String, String> hashMap = new HashMap<String, String>();
// adding each child node to HashMap key => value
//hashMap.put(TAG_RANK, rank);
hashMap.put(TAG_NAME, name);
hashMap.put(TAG_IMAGEURL, imageurl);
// adding HashMap to ArrayList
chartItemList.add(hashMap);
}
;
}
catch (JSONException e) {
e.printStackTrace();
}
runOnUiThread(new Runnable() {
public void run() {
list=(ListView)findViewById(R.id.list);
// Getting adapter by passing xml data ArrayList
adapter = new LazyAdapter(JsonActivity.this, chartItemList);
list.setAdapter(adapter);
// Click event for single list row
list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
}
});
}
});
return null;
}
//Removes the progress dialog when the data has been fetched
protected void onPostExecute(String args) {
progressDialog.dismiss();
}
}
}