我希望在我的应用程序从数据库加载数据时显示加载过程。
这是我的Java文件。
我必须在哪里放置显示加载过程的函数?
public class AksesServerActivity extends ListActivity {
private static String link_url = "http://plnskh.zz.mu/android/berita/cekdaftar.php";
private static final String AR_ID = "id";
private static final String AR_JUDUL = "judul";
private static final String AR_CONTENT = "content";
JSONArray artikel = null;
ArrayList<HashMap<String, String>> daftar_artikel = new ArrayList<HashMap<String, String>>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
JSONParser jParser = new JSONParser();
JSONObject json = jParser.AmbilJson(link_url);
try {
artikel = json.getJSONArray("artikel");
for(int i = 0; i < artikel.length(); i++){
JSONObject ar = artikel.getJSONObject(i);
String id = ar.getString(AR_ID);
String judul = ar.getString(AR_JUDUL);
String content = ar.getString(AR_CONTENT).substring(0,100)+"...(baca selengkapnya)";
HashMap<String, String> map = new HashMap<String, String>();
map.put(AR_ID, id);
map.put(AR_JUDUL, judul);
map.put(AR_CONTENT, content);
daftar_artikel.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
this.adapter_listview();
}
public void adapter_listview() {
ListAdapter adapter = new SimpleAdapter(this, daftar_artikel,
R.layout.list_item,
new String[] { AR_JUDUL, AR_CONTENT, AR_ID}, new int[] {
R.id.judul, R.id.content, R.id.kode});
setListAdapter(adapter);
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,int position, long id) {
String kode = ((TextView) view.findViewById(R.id.kode)).getText().toString();
Intent in = new Intent(AksesServerActivity.this, DetailAksesServer.class);
in.putExtra(AR_ID, kode);
startActivity(in);
}
});
}
}
答案 0 :(得分:1)
public class LongOperation extends AsyncTask<String, String, String>
{
ProgressDialog pdialog;
@Override
protected String doInBackground(String... params) {
JSONParser jParser = new JSONParser();
JSONObject json = jParser.AmbilJson(link_url);
try {
artikel = json.getJSONArray("artikel");
for(int i = 0; i < artikel.length(); i++){
JSONObject ar = artikel.getJSONObject(i);
String id = ar.getString(AR_ID);
String judul = ar.getString(AR_JUDUL);
String content = ar.getString(AR_CONTENT).substring(0,100)+"...(baca selengkapnya)";
HashMap<String, String> map = new HashMap<String, String>();
map.put(AR_ID, id);
map.put(AR_JUDUL, judul);
map.put(AR_CONTENT, content);
daftar_artikel.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
pdialog.dismiss();
this.adapter_listview();
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
pdialog = new ProgressDialog(NewsActivity.this);
pdialog.setMessage("Loading");
pdialog.show();
}
}
有关异步任务及其方法的更多说明,请查看here
答案 1 :(得分:0)
您必须使用AsyncTask
类,覆盖doInBackground
方法来执行数据库提取,使用onPreExecute
方法显示您的加载,并onPostExecute
隐藏它。您可以参考AsynTask process
和AsynTask post
了解更多信息