我的活動查詢我的分析數據庫,然後重新查詢數據。數據以名稱的形式存儲在列表視圖中。但我不知道如何檢查列表視圖是否爲空。我希望它發佈警報,說明列表視圖在事件發生時是空的。這是我的活動如何檢查列表視圖是否爲空
public class OfferPage extends Activity {
String obj;
ProgressDialog mProgressDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_offer_page);
Intent i = getIntent();
obj = i.getStringExtra("RestName");
populateList(obj, "Restraunt");
}
private void populateList(final String Value, final String Key) {
ParseQueryAdapter.QueryFactory<ParseObject> factory = new ParseQueryAdapter.QueryFactory<ParseObject>() {
@Override
@SuppressWarnings({ "unchecked", "rawtypes" })
public ParseQuery create() {
ParseQuery query = new ParseQuery("Offers");
query.whereEqualTo(Key, Value);
return query;
}
};
ParseQueryAdapter<ParseObject> adapter = new ParseQueryAdapter<ParseObject>(
this, factory);
adapter.setTextKey("Offer");
adapter.addOnQueryLoadListener(new OnQueryLoadListener<ParseObject>() {
@Override
public void onLoading() {
mProgressDialog = new ProgressDialog(OfferPage.this);
mProgressDialog.setTitle("Searching for Offers");
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
mProgressDialog.show();
}
@Override
public void onLoaded(List<ParseObject> objects, Exception e) {
mProgressDialog.dismiss();
}
});
final ListView listView = (ListView) findViewById(R.id.offerList);
listView.setAdapter(adapter);
}
我的主要問題我似乎無法弄清楚如果列表是空的檢查。有什麼建議麼?