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我试图显示一个进度对话框,同时从web上填充信息,填充从中创建ListView的sqlite数据库。我创建了一个异步类,在下载信息时显示进度对话框,但在此之后,列表视图为空。这可能是因为在异步之前已经加载了listview。那么,如何重新加载列表视图或以正确的方式进行操作呢?以下是我迄今为止(留出了后台处理,因为它太长时间displag):Android:从数据库异步填充后从数据库中加载列表视图
private class DownloadInfo extends AsyncTask <Void, Void, Void>{
//////////////////Open Dialog before execution ///////////
private ProgressDialog dialog;
protected void onPreExecute(){
dialog = new ProgressDialog(CandidatesList.this);
dialog.setMessage("Loading Candidates from Webserver");
dialog.setIndeterminate(true);
dialog.setCancelable(false);
dialog.show();
}
///////////////Background Processing//////////////////
@Override
protected Void doInBackground(Void... dbArray) {
////Load information from webserver and put it in sqlite///
return null;
}
///////After the processing is done //////////////
protected void onPostExecute(Void unused) {
dialog.dismiss();
}
}
而上创建如下:
DownloadInfo task = new DownloadInfo();
task.execute();
Cursor c = db.getAllCandidates();
candidates = new String[c.getCount()];
if (c.moveToFirst()) {
int i = 0;
do {
candidates[i] = c.getString(1);// insert Name into candidate
// Array
i++;
} while (c.moveToNext());
}
setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item,
candidates));
请帮帮忙, 谢谢
在postExecute中调用notifyDataSetChanged()?而在什么? notifyDataSetChanged()是SimpleCursorAdapter的继承方法。 – Diaa 2012-04-20 19:37:47
一种解决方案是将您的AsyncTask传递给您的适配器,并且在postExecute()中调用notifyDataSetChanged()。 – Sam 2012-04-20 19:50:31