I been using custom adapters based on the BaseAdapter and I usually populate my data at the getView() funtion.
Now I'm trying to write my custom adapter for my database cursor which now will be based on a CursorAdapter.
I'm getting confused where I should do the populating work? Along with how do I implement my inflating and populating "smart/efficient code based on RomainGuy presentation."
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I have a Custom Cursor Adapter. It shows a list of installed applications with an icon, name and checkbox on each line item. I cache the list of applications in a database for faster retrieve and to store the state of the checkbox. However, I can't store the application icon in the db because sqlite doesn't support blobs. They list works rather well except that it is "janky" as described by Brad Fitzpatrick at Google IO (https://wave.google.com/wave/waveref/ googlewave.com/w+3kgmObZwO ). I'm trying to make my app non-janky by following the tutorial here: [url]... but I'm having trouble.
The reason my list is janky is because I look up each icon as you scroll down the list. drawable = pm.getApplicationIcon(c.getString(c.getColumnIndex(SmartLockDbAdapter.KEY_PACKAGE)));
getApplicationIcon takes too long to return to make for a smooth scrolling list. I would like to perform the action in the background with an AsyncTask but because bindView gets called repeatedly in a short time span, my icons end up with the wrong list item. I need help.
I've posted my whole ListActivity below in hopes that it helps other people. It's much harder to find an example of a working CursorAdapter then it is an ArrayAdapter.
CODE:........................
I've got a schedule Class, which is simply a custom ViewGroup (with custom onMeasure() and onLayout()), which enables me to place childs(=events) with LayoutParams for column/row start and column/row end. The number of childs and their LayoutParams depend on database entries.
Now I'm trying to add childs (events) from my database. I'd have to use a Cursor Adapter, so my schedule Class has to extend ListView, right? I tried that but the newView() method of the adapter is never called. Why not? My custom ListView doesn't ask the adapter for childs, no childs are added. I also can't add the childs by hand calling schedule.addView() if I extend from AdapterView.
How can I add events to the schedule with the data from the cursor?
The structure of some of my activities is a simple ListView with a custom CursorAdapter. The cursor is created in onCreate() on the activity from a SQLite database. The problem is that querying the SQLite database can be quite slow at times with lots of data (and let's assume I've already optimized the sql query as much as possible). Because it occurs in onCreate() on the UI thread, I get ugly black screens when opening the activity, which sometimes turn into ANRs, on a slow phone like the G1. I want to load the cursor in a background and show "Loading.." on screen while doing so. I saw AsyncQueryHandler used extensively in the framework, but this seems a solution geared more towards Content Providers and not application-local SQLite databases. I then thought of trying to load the cursor in a background thread, but realize that this might be problematic, as the CursorAdapter should be instantiated in onCreate() and should take a cursor as a parameter. The latest thought I had was to instantiate an empty MatrixCursor in onCreate() and pass that to the cursor adapter, while kicking off a thread/TimerTask to query the database. Then, on database cursor load, call cursorAdapter.change Cursor to the properly filled cursor. This doesn't seem very elegant and seems quite wasteful, however.
View 10 Replies View RelatedNot sure of the absolute utility of this but seems as though it should be possible and useful. Can you extend ContentProvider to provide URIs representing new queries (i.e., joins across multiple tables not specified by existing URIs) for an existing system database? The alternative seems to be that I need to write a series of cursor queries then join them -- seems like a lot of unnecessary code duplication.
I have been trying this for the contacts database as an exercise, but no love so far. The crux seems to be that I cannot open a database in another package during the setup phase. Am I just completely out in left field here? It's possible as I am new to both Java and Android.
I get records from the system by quering a ContentResolver. I maintain the order of the items in the database. So I want to display the items in the order taken from my database.
How do I merge these two informations?
I am looking after an alternative way now. As what I ideally want is:
Get order of contacts by a custom order held in my database (this involves joining CR with my DB cursor, and doing an order by, later seams it's not possible with CursorJoiner) but there is more, if the join is not unique I want to sort by contact's name as last measure
Which is impossible using Cursor and Joiners, because of the missing feature of order bys, also I need to return a Cursor, as I will be using the in an ExpandableList
Also this translated to TSQL it would look like
select * from contactsdata
left join category on contactsdata.catid=category.id
order by category.pos asc, contact.display_name asc
So I am looking now after an alternative. I have in mind to load in a temporary DB table all data from CR, then do the query on the temporary table where I can join tables and do order bys? How does this sound to you?
CODE:...........................
View 1 Replies View RelatedI've written an APP the uses has a small SQL lite DB and using a cursor adapter I can retrieve the records and populate a list view with them. from there I can get the Id of a selected item and delete it from the DB which works great. the issue I have is that as the DB grows deleting one row at a time would be slow and frustrating so I wanted to know if there was any way to allow multiple selections possibly with check boxes or by even changing the text color of the items selected so that I can retreiving their relative ID's.
I have read some posts that talk about custom cursor adapters but I am not sure how to adapt them to my code.
I have posted my code below.
CODE:.........................
I have read the Gallery2.java example, which show how to map a Column's value to an element in the view I want to create (in this case, it maps 'NAME' to text1 element0. But what if I have a Button in my view, how can I know which Person is being clicked? or how can I query the person's info when a button in the new is clicked?
From the Gallery2.java example:
SpinnerAdapter adapter = new SimpleCursorAdapter(this,
// Use a template that displays a text view
android.R.layout.simple_gallery_item,
// Give the cursor to the list adatper c,
// Map the NAME column in the people database to...
new String[] {People.NAME},
// The "text1" view defined in the XML template
new int[] { android.R.id.text1 });
Gallery g = (Gallery) findViewById(R.id.gallery);
We are connecting to a number of WebServices and fetching a lot of structured data(XML). We are parsing this data and storing them into SQLite tables. This part of the application runs periodically in the back ground.
On the foreground, the data fetched is displayed in ListViews. We have used ArrayAdapter to back these lists up. The thing is, every time the Actvity starts or data set is refreshed, we have to load the ArrayLists by querying the database and call notifyDataSetChanged() on the Adapter. This slows down the application and affects the User experience.
Question: 1. I'd imagine using a CursorAdapter might result in performance gain, since the framework will take care of managing the cursor. Is this assumption valid? 2. Will the CursorAdapter take care of reflecting updates to the database on the screen automatically? 3. Will I have to write a ContentProvider if I choose to use CursorAdapters? 4. Are there any other considerations that we need to make?
CursorAdapter is great, i'm a big fan. I notice that both newView() and bindView() are passed Cursors, indicating that extracting stuff from the Cursor and sticking it in the view should happen inside those overrides.
however in the source for CursorAdapter.getView() i see that bindView() gets called whether the view is recycled or not. in the new view case, this causes a redundant Cursor to View copy.
IMHO, CursorAdapter should call newView() if the view couldn't be recycled, or bindView() if it could.
I have a ListView which is populated using a CursorAdapter. I'd also like to have some separators in my ListView. I have accomplished this with an ArrayAdapter, but I'm not sure how to accomplish this with a CursorAdapter. Are there any strategies for doing so? Or am I out of luck?
View 1 Replies View RelatedI have a custom CursorAdapter that is taking items from a database and displaying them in a listview. If possible, I would like to display only certain elements based on some boolean value within a database element. Here is something similar to what I would like to do:
package itp.uts.program;
import android.content.Context;
import android.database.Cursor;
import android.graphics.Color;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CursorAdapter;
import android.widget.TextView;
//Adapter tests if an element is read or unread, and bolds the items that are unread
public class BoldAdapter extends CursorAdapter. Code...
I have table with 3 columns which is binded to an XML document with three text views.
CODE:........
Depending on the value store in the third column, I have to decide whether i should display this row or not
How should, I go about with this.
This is what I have so far :
CODE:...............
I successfully binded a spinner widget to a simple cursor adapter, but I started having problems when I tried to add a new item to the table which feeds the spinner by clicking an "add new item" button. The idea was to launch a new activity which returns the rowid of the just added element, and use it to set the new position.
What I basically did is to implement something like:
break; in the "onActivityResult" method, the rowid has the correct value but setSelection has no effect. I also tried to force the argument to some other values, but still with no result. If I call it in the onCreate method, it works beautifully. Moreover, I am still not sure that setSelection is the right method to call, since its arg is named "position" in the doc, while I am passing an "id".
I want to write a short app for getting some info from contacts, the first list screen I have should display the user Image (or an Image from resources if no such image exists) an the user display name. The problem is I don't seem to find a query that will provide me with the display name and a user id And the image URI in the same query. Moreover I'm aware of the fact that if the user has no image and the URI is empty or null i will most likely to get an exception while the adapter calls setViewImage(). Is there a simple way around it or should I override the setViewImage() or bindView() methods?
Also about the query, any chance I can make a single query for contact URI, _ID, contact_id and display name? my current queries: To get the contacts:
private Cursor getContacts() { Uri uri = ContactsContract.Data.CONTENT_URI;
String[] projection = new String[] ContactsContract.Data._ID,ContactsContract.Data.CONTACT_ID,
ContactsContract.Data.DISPLAY_NAME };
String selection = ContactsContract.Data.MIMETYPE + " = ?";
String[] selectionArgs = {ContactsContract.CommonDataKinds.StructuredPostal.CONTENT_ITEM_TYPE};
String sortOrder = ContactsContract.Contacts.DISPLAY_NAME + " ASC";
return managedQuery(uri, projection, selection, selectionArgs, sortOrder); }
If I have a contact id and want the image:
int _id = m_cursor.getColumnIndex(ContactsContract.Contacts._ID);
//try to retrieve the photo, if exists.
Uri photoUri = ContentUris.withAppendedId(ContactsContract.Contacts.CONTENT_URI,
m_cursor.getLong(_id)); InputStream is = ContactsContract.Contacts.openContactPhotoInputStream(m_context.getContentResolver(), photoUri);
Here I get from a cursor with _ID column the id and then creating the uri, I know I can get a row number but I'm not familiar enough with contentProvider to know how to join tables to get it all in one query (if even possible).
can anyone tell me what im doing wrong with my cursorAdapter? its making my display choppy when i scroll. I used to have it within a getview but was ripped (rightfully so) on IRC several times because thats not the right place for it. Im still learning and just trying to correctly wrap my head around things.
http://pastebin.com/Dc5ppHUM
I have the following code to intantiate a SimpleCursorAdapter to use with a ListView. As you can see I have passed the R.layout.log_item to display the list items, and one value/control to bind to (TripDate).
SimpleCursorAdapter sca = new SimpleCursorAdapter(this, R.layout.log_item,c,new String[] {DBAdapter.KEY_LOG_TRIPDATE},new int[]{R.id.txtTripDate});
This works. I currently only have one widget in the layout xml, a TextView to hold the TripDate.
How do I pass multiple binding parameters for the additional widgets in the layout? So I can also display other info.
I have a ListView populated via a CursorAdapter. I give my user the ability to alter the data in the list. For example, the user can mark a row as being unread (the data are messages).
Suppose my user marked a row unread. Would a proper implementation mark the row in the database as read and then requery the Cursor?
I cant find a way to save the checkbox state when using a Cursor adapter. Everything else works fine but if i click on a checkbox it is repeated when it is recycled. Ive seen examples using array adapters but because of my lack of experience im finding it hard to translate it into using a cursor adapter. Could someone give me an example of how to go about it.code...
View 3 Replies View RelatedI've overriden runQueryOnBackgroundThread and done what I've needed to do for the corrent query to be excuted with a given constraint. My current challenge is figuring out how to actually pass in the constraint. I've got an ActivityList which I'd like to filter on a stored preference. I'm thinking I will need to perform a filter during onStart such that the most recent preference changes are picked up. All that is in place, just not clicking on how I'd actually cause the filter to happen!
View 2 Replies View RelatedI have a list which shows data from a database using a cursor adapter. Using Menu option I am updating my database (inserting more rows deleting existing rows). When Menu operation completes, I want contents of list should show updated contents.
I have tried using cursor.requery(); (or explicitly querying cursor again) and using adapter.notifydatasetchanged(), but with this list of contents are not updated.
How can I refresh the contents of the list.
I have table with 3 columns which is binded to an XML document with three text views.
CODE:........
Depending on the value store in the third column, I want to change the text color in R.id.c. How should, I go about with this.
This is what I have so far :
COD:...............
I have seen examples implementing a custom Filter. The Android developer docs talk about implementing a Filterable interface. Does anyone have any advice and/or sample code on the best way to implement filtering in a ListView ?
View 2 Replies View RelatedIn the API Demo, there is example on using Simple Cursor Adapter. However, it is using the MediaS tore cursor. Is there any method so that I can use other external cursor prepare by SQL database. I don't know what should I input to the from String.
View 2 Replies View RelatedHere is my code for my db class:
package one.two;
import java.util.List;
import android.app.ListActivity;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import java.util.ArrayList;
public class DBAdapter extends ListActivity
{public String status = "status";
public String id = "id";
public String arrival = "arrival";
public String destination = "destination";
public String ferry = "ferry";
private static String DB_PATH = "/data/data/one.two/databases/";
private static final String DATABASE_NAME = "ferry.db";
private static final String DATABASE_TABLE = "port";
public static Context context;
public Cursor c;
public static SQLiteDatabase DbLib;
//overloaded non-null constructor
public DBAdapter(Context context) {
DbLib = context.openOrCreateDatabase(DATABASE_NAME,
SQLiteDatabase.CREATE_IF_NECESSARY,null);
System.out.println("OpenOrCreateDB Done");
} public class DatabaseHelper extends SQLiteOpenHelper {
Context context;
DatabaseHelper(Context context){
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.context = context;
}//end constructor DatabaseHelper
// ---closes the database---
public void close() {
DBHelper.close();
}//end close()
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion){
}//end onUpgrade()
@Override
public void onCreate(SQLiteDatabase db){
}//end onCreate()
}// end class DatabaseHelper
private static DatabaseHelper DBHelper;
private static final int DATABASE_VERSION = 1;
public static ArrayList<String> getAllTitles(){
ArrayList<String> port = new ArrayList<String>();
Cursor c=null;
c = DbLib.query("port"
new String[] { "status", "id", "arrival",
"destination", "ferry" }, null, null,
null, null, null);
try {
if (c!=null) { // start - when there is at least 1 record
System.out.println("Cursor is NOT NULL");
int i =0;
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
{// Debug Stm
System.out.println("Record No. "+i);
System.out.println(c.getString(0));
System.out.println(c.getString(1));
System.out.println(c.getString(2));
System.out.println(c.getString(3));
System.out.println(c.getString(4));
// Assign database cursor.records to arraylist
port.add(i,c.getString(0));
port.add(i,c.getString(1));
port.add(i,c.getString(2));
port.add(i,c.getString(3));
port.add(i,c.getString(4));
i = i + 1;
} } // end - where there is at least 1 record
} finally {
if (c!=null) {
c.close();
} } return port;
}//end getAllTitles()
public void open() {
//Open the database
String myPath = DB_PATH + DATABASE_NAME;
DbLib = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
} }//end class DBAdapter
My Arrival class
package one.two;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
public class Arrival extends ListActivity
{ private ListView listView;
/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState)
{ ArrayList<String> retList = new ArrayList<String>();
System.out.println("Start onCreate Function");
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
System.out.println("In onCreate Function");
System.out.println("In of GetData");
DBAdapter db = new DBAdapter(this);
System.out.println("DB Open");
db.open();
System.out.println("DB Opened");
retList = getData();
System.out.println("Out of GetData");
// force count no. of records in table
// dump to check index
int cnt = 2;
int i=0;
for (i = 0; i<cnt; i++)
System.out.println(retList.toString());
listView = (ListView) findViewById(android.R.id.list);
SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, android.R.id.list, null, null, null);
this.setListAdapter(mAdapter);
// db.close();
} @SuppressWarnings("static-access")
public static ArrayList<String> getData()
{ ArrayList<String> items = DBAdapter.getAllTitles();
// titles ???? redundant
//ArrayList<String> titles = new ArrayList<String>(items);
System.out.println("Return a LIST titles");
return items;
} }
I am seeing the exception in 'adb logcat'.But I don't know if it is caused by my application or android platform.Can you please give me any idea how to troubleshoot this exception?
View 3 Replies View RelatedI'm developing an Android application with a database. That database will have more than three tables. Now I'm working on a class called DBAdapter to access the SQLite Database. DBAdpater will have five methods for every table on database (insertEntry, removeEntry, getAllEntries, getEntry and updateEntry). So, if I have five table, DBApadter will have more than twenty-five methods. I think is so huge. How may DBAdapter classes should be?
View 1 Replies View RelatedHow do you populate a spinner from a cursor accessing an SQLite database?
View 2 Replies View RelatedI am having some trouble working with the SQLite database. I am able to create the database, add to it, and delete from it with no problem by following the Notepad examples, but I am trying to avoid duplicates and therefore want to check to see if an entry exists already.
Below is the code I have for testing to see if a game exists. I get the correct Log message of "No Games" when there are no games, as well as the correct value for column from getColumnIndex which is proven to me by the log printout telling me that column = 1.
The error message that I receive if I don't catch the exception says "Caused by android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 1
Where is Index -1 being requested if my call to getColumnIndex is returning 1? Code...