how to remove black screen when switching activity( is not working) - on android

Question

in my app, i am switching one activity to another activity (Main.java to Feature_Screen.java). In the Feature_Screen(second activity) i am going to download large no of data and image to set in a grid view. so that i use Async Task for download it. although i use async task in second activity i get black screen while switching Main.java to Feature.java. i search in google but all the answers says use Async Task.

example coding:

public class Main extends TabActivity{

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.tabbar);
    .................
    intent = new Intent().setClass(this, Featured_Screen1.class);
    spec = tabHost.newTabSpec("home").setIndicator("",
            res.getDrawable(R.drawable.top_book_icon)).setContent(intent);
    tabHost.addTab(spec);
    ...........
}
}

In Feature_Screen1.java(Second.java):

public class Feature_Screen1 extends Activity{

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.feature);
    .................
      new Content_load().execute();
    ...........
}

 class Content_load extends AsyncTask<Void, Void, Void> 
   {
ProgressDialog dialog = new ProgressDialog(SignInPage.this);

protected void onPreExecute() { 
    dialog.setMessage("Please wait...");
    dialog.setCancelable(false);
    dialog.show();
}

protected void onPostExecute(Void unused) {
    dialog.dismiss();
}

protected Void doInBackground(Void... arg0) {
      ..........
  return null;
   }
  } 

}

my problem is how to avoid black screen while switching between activities? please help me.

Answer 1

Finally I found the answer for black screen problem..

Use AsyncTask like below, this worked for me, if you face any problems let me know

public class SyncroniseRecords extends AsyncTask<Void, Void, Void>
{  
    @Override
    protected void onPreExecute()
    {  
        super.onPreExecute();
        dialog.setMessage("Please wait...");
        dialog.setCancelable(false);
        dialog.show();

    } 
    @Override 
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
        // Things to be done while execution of long running operation is in progress. For example updating ProgessDialog
     }

    @Override 
    protected void onPostExecute(Void result)
    { 
           dialog.cancel();
    }
    @Override
    protected Void doInBackground(Void... params) {

        return null;
    }
} 

This will launch the Activity without any Black Screen. Using onPreExecute you can display the Progressbar.Once the process gets completed you can cancel it in OnPostExecute().