我正在从网站以 JSON 格式获取信息，并使用 AsynTask 将该信息显示到我的应用程序中。问题是在第一次我的进度对话框显示良好并在将内容加载到应用程序后隐藏。但是当我使用滚动视图加载更多时，进度对话框出现并在加载后立即隐藏，同时进度对话框再次打开而不隐藏，滚动视图在后台再加载一次数据。我只想加载一次每次使用 Scroll-View 加载更多数据后。进度对话框没有隐藏，它一直在运行我的应用程序。在这一点上我很震惊。
基本上我注意到我的滚动视图指示器在底部碰撞了两次，因为这个滚动视图触发了两次。我怎样才能停止它并在每次滚动后仅限制一次。
还有一件事要分享，在 Froyo 2.2 中一切都很好，而在 2.3 到 4.2 中却没有。请帮助我。提前致谢。
下面是我的代码。
package com.example.lmf;
import java.net.URLEncoder;
import org.json.JSONArray;
import org.json.JSONObject;
import com.example.lmf.ObservableScrollView.ScrollViewListener;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.MenuItem.OnMenuItemClickListener;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.LinearLayout.LayoutParams;
import android.widget.Toast;
public class searchClassified extends Activity implements ScrollViewListener
{
ObservableScrollView scrollView;
ProgressDialog _progressDialog;
int page_no = 1;
String k = "";
final static String URL = "http://www.lmf.com.pk/admin/json.php?YOUR URL OF JSON";
final getInternetData obj = new getInternetData();
public ImageLoader imageLoader = null;
Context context = this;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.get_classified);
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
scrollView = (ObservableScrollView) findViewById(R.id.my_scroll);
scrollView.setScrollViewListener(this);
imageLoader = new ImageLoader(this);
String s = getIntent().getExtras().getString("query")!= "" ? getIntent().getExtras().getString("query") : "";
EditText et = (EditText) findViewById(R.id.query);
et.setText(s);
k = "all="+URLEncoder.encode(s);
//showProgress(context);
new getBackgroundData().execute();
}
public void onScrollEnded(ObservableScrollView scrollView, int x, int y,
int oldx, int oldy) {
// TODO Auto-generated method stub
page_no = page_no + 1;
k = k+"&page_no="+page_no;
//showProgress(context);
getBackgroundData d1 = new getBackgroundData();
d1.execute();
if(d1.getStatus()==AsyncTask.Status.FINISHED) {
d1 = null;
_progressDialog.dismiss();
}
}
public void searchAds(View v)
{
EditText query = (EditText) findViewById(R.id.query);
String q = query.getText().toString();
if(q == "" || q == "search")
{
Dialog d = new Dialog(this);
d.setTitle("Enter Valid Search Parameter");
d.show();
}
else
{
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
Intent i = new Intent(searchClassified.this,com.example.lmf.searchClassified.class);
i.putExtra("query", ""+q+"");
startActivity(i);
}
}
public void showProgress(Context c)
{
_progressDialog = ProgressDialog.show(
c,
"Please wait",
"Performing task..."
);
}
public void hideProgress()
{
_progressDialog.dismiss();
}
//////////// Async Class
private class getBackgroundData extends AsyncTask<Void, Integer, JSONArray>
{
protected void onPreExecute()
{
_progressDialog = new ProgressDialog(context);
_progressDialog.setMessage("Loading...");
_progressDialog.show();
}
@Override
protected JSONArray doInBackground(Void... params)
{
try
{
JSONArray array = obj.getDATA(k,URL);
return array;
}
catch(Exception e)
{
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(JSONArray array)
{
LinearLayout sv = (LinearLayout) findViewById(R.id.data);
try
{
for (int i = 0; i <array.length(); i++) {
JSONObject row = array.getJSONObject(i);
//// TextView Creation start here /////////
TextView tv = (TextView)getLayoutInflater().inflate(R.layout.tvtemplate, null);
tv.setText(row.getString("post_title"));
tv.setTextColor(Color.BLACK);
tv.setTextSize(14);
tv.setPadding(8, 6, 0, 12);
tv.setFocusable(true);
tv.setLayoutParams(new LayoutParams(
LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
//// TextView Creating Ends here /////////
//// Horizontal Line Creating here /////////
View v = new View(searchClassified.this);
LinearLayout.LayoutParams viewLp = new LayoutParams(LayoutParams.MATCH_PARENT, 1);
viewLp.setMargins(0, 4, 0, 4);
v.setLayoutParams(viewLp);
v.setBackgroundColor(Color.LTGRAY);
//// Horizontal Line Creating Ends here /////////
//// Image Creating Starts from here /////////
LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
lp.setMargins(3, 0, 15, 8);
lp.width = 70;
lp.height = 80;
ImageView imageView = new ImageView(searchClassified.this);
String[] parts = row.getString("post_img").split("/");
int last_index = parts.length - 1;
String image_name = "thumb_"+parts[last_index];
String str = "";
for(int j=0; j<last_index; j++)
{
str += parts[j]+"/";
}
String path = "http://www.lmf.com.pk/"+str+image_name;
imageLoader.DisplayImage(path, imageView);
//// Image Creating Ends here /////////
// Creating LinearLAyout /////////
LinearLayout l1 = new LinearLayout(searchClassified.this);
l1.setOrientation(LinearLayout.HORIZONTAL);
l1.setHapticFeedbackEnabled(true);
l1.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
l1.setId(obj.convertStrtoInt(row.getString("post_id")));
l1.setHapticFeedbackEnabled(true);
l1.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
Intent i = new Intent(searchClassified.this,com.example.lmf.adsDetail.class);
i.putExtra("id", v.getId());
startActivity(i);
}
});
l1.addView(imageView, lp);
l1.addView(tv);
sv.addView(l1);
sv.addView(v);
}
_progressDialog.hide();
_progressDialog.dismiss();
_progressDialog = null;
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
/////////// Ends Here
public boolean onCreateOptionsMenu(Menu menu)
{
MenuItem item = menu.add ("Quit");
item.setOnMenuItemClickListener (new OnMenuItemClickListener()
{
public boolean onMenuItemClick (MenuItem item)
{
//clearArray();
finish();
return true;
}
});
return true;
}
}