Android ListView refresh
I have a Listview which pulls and displays data from a sqlite DB. Data in the first column of the DB is displayed in the ListView and when clicked, an Activity starts showing the rest of the column associated with the first column. When the data is edited the ListView needs to be updated to reflect this, but it doesn't show the updates unless the application is restarted.
I've tried calling, notifyDataSetChanged() and startActivityForResult() in my onResume() method but that didn't work. What method should I use to accomplish updating the ListView in my current code?
I understand a SimpleCursorAdapter may be used and I have tried to implement that code with no success. I'm a novice and need actual code to understand what needs to be done.
public class LoginList extends Activity implements OnClickListener, OnItemClickListener {
private ListView loginList;
private Button webLogin;
private ListAdapter loginListAdapter;
private ArrayList<LoginDetails> loginArrayList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login_listview);
loginList = (ListView)
findViewById(R.id.loginlist);
loginList.setOnItemClickListener(this);
webLogin = (Button)
findViewById(R.id.button3);
webLogin.setOnClickListener(this);
loginArrayList = new ArrayList<LoginDetails>();
loginListAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, populateList());
loginList.setAdapter(loginListAdapter);
}
@Override
public void onClick (View v) {
Intent webLoginIntent = new Intent (this, LoginPlusActivity.class);
startActivity(webLoginIntent);
}
public List<String> populateList () {
List<String> webNameList = new ArrayList<String>();
dataStore openHelperClass = new dataStore (this);
SQLiteDatabase sqliteDatabase = openHelperClass.getReadableDatabase();
Cursor cursor = sqliteDatabase.query(dataStore.TABLE_NAME_INFOTABLE, null, null, null, null, null, dataStore.COLUMN_NAME_SITE, null);
startManagingCursor(cursor);
while (cursor.moveToNext()) {
String sName = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_SITE));
String wUrl = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_ADDRESS));
String uName = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_USERNAME));
String pWord = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_PASSWORD));
String lNotes = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_NOTES));
LoginDetails lpDetails = new LoginDetails();
lpDetails.setsName(sName);
lpDetails.setwUrl(wUrl);
lpDetails.setuName(uName);
lpDetails.setpWord(pWord);
lpDetails.setlNotes(lNotes);
loginArrayList.add(lpDetails);
webNameList.add(sName);
}
sqliteDatabase.close();
return webNameList;
}
@Override
protected void onResume() {
super.onResume();
loginListAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, populateList());
loginList.setAdapter(loginListAdapter);
}
@Override
public void onItemClick(AdapterView<?> arg0 , View arg1, int arg2, long arg3) {
Toast.makeText(getApplicationContext(), "Selected ID :" + arg2, Toast.LENGTH_SHORT).show();
Intent updateDeleteLoginInfo = new Intent (this, UpdateDeleteLoginList.class);
LoginDetails clickedObject = loginArrayList.get(arg2);
Bundle loginBundle = new Bundle();
loginBundle.putString("clickedWebSite",clickedObject.getsName());
loginBundle.putString("clickedWebAddress",clickedObject.getwUrl());
loginBundle.putString("clickedUserName",clickedObject.getuName());
loginBundle.putString("clickedPassWord",clickedObject.getpWord());
loginBundle.putString("clickedNotes",clickedObject.getlNotes());
updateDeleteLoginInfo.putExtras(loginBundle);
startActivityForResult(updateDeleteLoginInfo, 0);
}
}
Answer
This is exactly what a Loader is great for. I suggest you create a SimpleCursorAdapter to bind the DB to the UI (ListView in this case), a ContentProvider to interface with the DB, and a CursorLoader to monitor the DB for changes, and update the UI when necessary. The Loader will handle all DB changes and update your ListView by simply updating your adapter. It seems like a lot of work up front, but is incredibly powerful once configured, and will work through the entire Android lifecycle.
These tutorials should be helpful: