我是 android 编程新手。我想知道如何解析网页并将特定内容提取到 ListView 中。最简单和最好的方法是什么？有人可以用下面给出的例子给我看一个例子吗？
URL = "Something.com"。
我想提取每个城市的名称和href链接。
安娜堡巴特尔克里克密歇根州
中部
底特律 地铁
弗林特
大急流城
谢谢你们，很抱歉提出这个基本问题。
问问题
7815 次
3 回答
3
查看下面的代码，如果您有任何疑问，请告诉我，并查看此链接，它可能会对您有所帮助
public class MainActivity extends Activity {
ListView mListView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// URL to the JSON data
String strUrl = "ur url/countries";
// Creating a new non-ui thread task to download json data
DownloadTask downloadTask = new DownloadTask();
// Starting the download process
downloadTask.execute(strUrl);
// Getting a reference to ListView of activity_main
mListView = (ListView) findViewById(R.id.lv_countries);
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException{
String data = "";
InputStream iStream = null;
try{
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while( ( line = br.readLine()) != null){
sb.append(line);
}
data = sb.toString();
br.close();
}catch(Exception e){
Log.d("Exception while downloading url", e.toString());
}finally{
iStream.close();
}
return data;
}
/** AsyncTask to download json data */
private class DownloadTask extends AsyncTask<String, Integer, String>{
String data = null;
@Override
protected String doInBackground(String... url) {
try{
data = downloadUrl(url[0]);
}catch(Exception e){
Log.d("Background Task",e.toString());
}
return data;
}
@Override
protected void onPostExecute(String result) {
// The parsing of the xml data is done in a non-ui thread
ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();
// Start parsing xml data
listViewLoaderTask.execute(result);
}
}
/** AsyncTask to parse json data and load ListView */
private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter>{
JSONObject jObject;
// Doing the parsing of xml data in a non-ui thread
@Override
protected SimpleAdapter doInBackground(String... strJson) {
try{
jObject = new JSONObject(strJson[0]);
CountryJSONParser countryJsonParser = new CountryJSONParser();
countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("JSON Exception1",e.toString());
}
// Instantiating json parser class
CountryJSONParser countryJsonParser = new CountryJSONParser();
// A list object to store the parsed countries list
List<HashMap<String, Object>> countries = null;
try{
// Getting the parsed data as a List construct
countries = countryJsonParser.parse(jObject);
}catch(Exception e){
Log.d("Exception",e.toString());
}
// Keys used in Hashmap
String[] from = { "country"
// Ids of views in listview_layout
int[] to = { R.id.tv_country};
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), countries, R.layout.lv_layout, from, to);
return adapter;
}
/** Invoked by the Android on "doInBackground" is executed */
@Override
protected void onPostExecute(SimpleAdapter adapter) {
// Setting adapter for the listview
mListView.setAdapter(adapter);
for(int i=0;i<adapter.getCount();i++){
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);
HashMap<String, Object> hmDownload = new HashMap<String, Object>();
hm.put("flag_path",imgUrl);
hm.put("position", i);
}
}
}
@Override
protected void onPostExecute(HashMap<String, Object> result) {
// Getting the path to the downloaded image
String path = (String) result.get("flag");
// Getting the position of the downloaded image
int position = (Integer) result.get("position");
// Getting adapter of the listview
SimpleAdapter adapter = (SimpleAdapter ) mListView.getAdapter();
// Getting the hashmap object at the specified position of the listview
HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(position);
// Overwriting the existing path in the adapter
hm.put("flag",path);
// Noticing listview about the dataset changes
adapter.notifyDataSetChanged();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
于 2013-01-04T06:37:35.627 回答
2
使用类似http://jsoup.org/的东西来获取 html 内容。
然后使用类似的东西
http://jsoup.org/cookbook/extracting-data/selector-syntax
提取网址。
然后
:matches(regex)：查找文本与指定正则表达式匹配的元素；例如 div:matches((?i)login)
为您要查找的网址做一个正则表达式。
我不确定这是否是你想要的。
于 2013-01-04T06:35:07.223 回答
0
我记得我做过一次，幸运的是我找到了那个代码。您只需要从您的活动中调用此 Intentservice 并且您需要在顶部指定网站名称（在 url 变量中）
public class parser extends IntentService {
public String url="http://www.mywebsite.com";
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
// shutdown();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub
return super.onStartCommand(intent, flags, startId);
}
private Timer t = new Timer();
byte[] buffer;
public timeCell() {
super("name");
// TODO Auto-generated constructor stub
}
@Override
protected void onHandleIntent(Intent arg0) {
// TODO Auto-generated method stub
t.schedule(new TimerTask(){
@Override
public void run() {
// TODO Auto-generated method stub
BufferedReader reader=null;
try {
reader = new BufferedReader(
new InputStreamReader(
new URL(url).openStream()));
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String line = null;
try {
line = reader.readLine();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Log.v("line was ", line); // printing is done here ;)
}
}
于 2013-01-04T06:46:42.467 回答