I am trying to display a progress dialog when the app runs for the first time since it installs database and takes a while to do that because of the DB size. Here is the ListAcitity that I am using:
package samples.employeedirectory;
import android.app.ListActivity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.WindowManager;
import android.widget.ListAdapter;
import android.widget.ListView;
public class EmployeeList extends ListActivity {
protected SQLiteDatabase db;
protected Cursor cursor;
protected ListAdapter adapter;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new progressBar().execute();
db = (new DatabaseHelper(this)).getWritableDatabase();
cursor = db.rawQuery("SELECT * FROM employeeList", new String[]{});
adapter = new qCursorAdapter(this, cursor);
// requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setListAdapter(adapter);
}
public void onListItemClick(ListView parent, View view, int position, long id) {
Intent intent = new Intent(this, displayEmployee.class);
Cursor cursor = (Cursor) adapter.getItem(position);
intent.putExtra("eID", cursor.getInt(cursor.getColumnIndex("eID")));
startActivity(intent);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.pref:
// Launch Preference activity
Intent intent = new Intent(this, Preferences.class);
startActivity(intent);
break;
}
return true;
}
}
I realized then that I can’t display progress bar before the activity starts. What is the best approach to achieve this?
Edit:
Using this code:
package samples.employeedirectory;
import android.app.ProgressDialog;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.os.AsyncTask;
public class progressBar extends AsyncTask<String, Void, String> {
protected Context context;
protected SQLiteDatabase db;
protected ProgressDialog dialog;
@Override
protected String doInBackground(String... params) {
db = (new DatabaseHelper(context)).getWritableDatabase();
return null;
}
/* (non-Javadoc)
* @see android.os.AsyncTask#onPostExecute(java.lang.Object)
*/
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
dialog.dismiss();
}
/* (non-Javadoc)
* @see android.os.AsyncTask#onPreExecute()
*/
@Override
protected void onPreExecute() {
// super.onPreExecute();
dialog = ProgressDialog.show(context, "",
"Please wait for few seconds...", true);
}
/* (non-Javadoc)
* @see android.os.AsyncTask#onProgressUpdate(Progress[])
*/
@Override
protected void onProgressUpdate(Void... values) {
// TODO Auto-generated method stub
super.onProgressUpdate(values);
}
}
I received these errors:
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): java.lang.RuntimeException: Unable to start activity ComponentInfo{samples.employeedirectory/samples.employeedirectory.EmployeeList}: java.lang.NullPointerException
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1659)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1675)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ActivityThread.access$1500(ActivityThread.java:121)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:943)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.os.Handler.dispatchMessage(Handler.java:99)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.os.Looper.loop(Looper.java:123)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ActivityThread.main(ActivityThread.java:3701)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at java.lang.reflect.Method.invokeNative(Native Method)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at java.lang.reflect.Method.invoke(Method.java:507)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:862)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:620)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at dalvik.system.NativeStart.main(Native Method)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): Caused by: java.lang.NullPointerException
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.Dialog.<init>(Dialog.java:141)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.AlertDialog.<init>(AlertDialog.java:67)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ProgressDialog.<init>(ProgressDialog.java:80)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ProgressDialog.<init>(ProgressDialog.java:76)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ProgressDialog.show(ProgressDialog.java:101)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ProgressDialog.show(ProgressDialog.java:90)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at samples.employeedirectory.progressBar.onPreExecute(progressBar.java:34)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.os.AsyncTask.execute(AsyncTask.java:391)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at samples.employeedirectory.EmployeeList.onCreate(EmployeeList.java:27)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-15 23:21:26.743: ERROR/AndroidRuntime(5170): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
you can use the Asyntask concept
in Preexecute() start the progress dialogue
in doinginbackground() method install the DB
in postexecute() stop the dialogue
refer this