Develop Reference

Android: Updating ListView

Well, I have read almost 50 links related to this question, but my code still not working.
I have a Custom adapter which extends SimpleCursorAdapter class, and I use that adapter to fill the ListView on onCreate method
private void populateListView()
{
String[] from = new String[] { SchemaHelper.TASK_DESCRIPTION, SchemaHelper.TASK_CREATED_ON, SchemaHelper.TASK_ID };
int[] to = new int[] {R.id.lv_row_description, R.id.lv_row_created_on};
tasksCursor = schemaHelper.getTasks();
startManagingCursor(tasksCursor);
tasksAdapter = new TasksAdapter(this, R.layout.tasks_listview_row, tasksCursor, from, to);
setListAdapter(tasksAdapter);
}
The App is a simple task manager, I want to update the ListView contents when the user submits a new task without calling setListAdapter() again.
I have tried notifyDataSetChanged (running on ui thread), invalidate, requery(deprecated)... almost everything.
I'm doing something wrong?
EDIT:
This is the method where I add a new task to the database
private void addTask(String description)
{
String message = "";
schemaHelper.open();
if(schemaHelper.isAlreadyInDatabase(description))
{
message = getString(R.string.task_already_exists);
}
else
{
message = getString(R.string.task_succesfully_added);
schemaHelper.insertTask(description);
populateListView();
newTask.setText("");
}
schemaHelper.close();
Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
}
ADAPTER CLASS:
private class TasksAdapter extends SimpleCursorAdapter
{
private LayoutInflater layoutInflater;
private Cursor cursor;
public TasksAdapter(Context context, int layout, Cursor c, String[] from, int[] to)
{
super(context, layout, c, from, to);
cursor = c;
cursor.moveToFirst();
layoutInflater = LayoutInflater.from(context);
}
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
if(cursor.getPosition() < 0)
{
cursor.moveToFirst();
}
else
{
cursor.moveToPosition(position); // Here throws the error
}
View row = layoutInflater.inflate(R.layout.tasks_listview_row, null);
TextView description = (TextView) row.findViewById(R.id.lv_row_description);
TextView createdOn = (TextView) row.findViewById(R.id.lv_row_created_on);
description.setText(cursor.getString(cursor.getColumnIndexOrThrow(SchemaHelper.TASK_DESCRIPTION)));
createdOn.setText(getString(R.string.added_on) + " " + TaskHelper.formatDateWithSuffix(cursor.getString(cursor.getColumnIndexOrThrow(SchemaHelper.TASK_CREATED_ON))));
return row;
}
}

i dont know much of the taskCursor and taskAdapter but i used ArrayAdapter i guess, well have a look in my code and take your own conclusions.
//LISTVIEW database CONTATO
ListView user = (ListView) findViewById(R.id.lvShowContatos);
//String = simple value ||| String[] = multiple values/columns
String[] campos = new String[] {"nome", "telefone"};
list = new ArrayList<String>();
Cursor c = db.query( "contatos", campos, null, null, null, null, "nome" + " ASC ");
c.moveToFirst();
String lista = "";
if(c.getCount() > 0) {
while(true) {
list.add(c.getString(c.getColumnIndex("nome")).toString());
if(!c.moveToNext()) break;
}
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, list);
user.setAdapter(adapter);

If you don't want to use requery() you can simply pass a new Cursor with the same query:
tasksCursor.close();
tasksCursor = schemaHelper.getTasks();
startManagingCursor(tasksCursor);
tasksAdapter.changeCursor(tasksCursor);
I assume that when you call addTask() you have already called populateListView() once. Try changing addTask() to this:
private void addTask(String description)
{
String message = "";
schemaHelper.open();
if(schemaHelper.isAlreadyInDatabase(description))
{
message = getString(R.string.task_already_exists);
}
else
{
message = getString(R.string.task_succesfully_added);
schemaHelper.insertTask(description);
// Remove call to populateListView(), just update the Cursor
tasksCursor.close();
tasksCursor = schemaHelper.getTasks();
startManagingCursor(tasksCursor);
tasksAdapter.changeCursor(tasksCursor);
newTask.setText("");
}
schemaHelper.close();
Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
}
If this "doesn't work", please be more specific. Is it throwing an error, if so what kind?
You are doing a little too much work in your adapter. Please watch Android's Romain Guy at Google Talks discuss adapters and getView(). However since you only want to pass one special string to your createdOn TextView, let's do something very different and override setViewText():
Try this:
public class TasksAdapter extends SimpleCursorAdapter {
String prefix;
public TasksAdapter(Context context, int layout, Cursor cursor, String[] from, int[] to) {
super(context, layout, cursor, from, to);
// This is constant so set it once and consider adding the space to the end of the String in strings.xml
prefix = getString(R.string.added_on) + " ";
}
#Override
public void setViewText(TextView v, String text) {
if(v.getId() == R.id.lv_row_created_on)
v.setText(prefix + TaskHelper.formatDateWithSuffix(text));
else
super.setViewText(v, text);
}
}
The rest of the data is taken care of with SimpleCursorAdapter's existing methods.

CheckedTextViews will randomly appear checked in a list if I click one further up the list

Ok, so this has been somewhat addressed alot on this site, however I do not believe the exact problem with what my code uses. I am filling a listView with CheckedTextViews which works completely. However when I click on an item it gets checked but when I scroll up and down random rows are also checked. I realize it must have something to do with how the ListView keeps track of the items. I am running into some errors at the moment. I attempted to fill a hashmap with the list of the rows so I can keep track which one is set to true and which are false. However I am not positive where to implement the map and try to fill it.
Here is my OnCreate
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.viewmenu);
//Get table name of menu clicked.
Bundle extras = getIntent().getExtras();
tableName = extras.getString("table");
// map each contact's name to a TextView in the ListView layout
String[] from = new String[] { "name" };
int[] to = new int[] { R.id.toppingCheckedTextView };
for(int i=0; i< from.length; i++){
map.put(i, false);
}
contactAdapter = new SimpleCursorAdapter(
ViewToppingListing.this, R.layout.toppings_list_item, null, from, to);
setListAdapter(contactAdapter); // set contactView's adapter
}
I attempt to place the map in the onCreate to fill it however it complains about a nullpointer.
Here is where I tried using the OnListItemClick method
#Override
protected void onListItemClick(ListView arg0, View arg1, int arg2, long arg3){
final int index = arg2 - arg0.getFirstVisiblePosition();
View v = arg0.getChildAt(index);
CheckedTextView ctv = (CheckedTextView) v.findViewById(R.id.toppingCheckedTextView);
if((Boolean)map.get(index) == true){
ctv.setChecked(true);
ctv.setVisibility(View.VISIBLE);
} else{
ctv.setVisibility(View.GONE);
}
}
I have read alot on this, and it seems that alot of solutions involves using getView(), however I don't know if that applies to my situation. Any help would be greatly appreciated!

First of all do you need a SimpleCursorAdapter? You set the adapter with a null cursor:
contactAdapter = new SimpleCursorAdapter(
ViewToppingListing.this, R.layout.toppings_list_item, null, from, to); // the third parameter is the cursor and you set it to null!
The behavior you see it's because of the ListView is recycling views and yes you'll have to implement your own adapter and override bindView(). The code bellow is based on another answer to a similar question maybe you'll want to look at it( Getting the selected View from ListView ). Here is an example:
public class TestCursorAdapter extends ListActivity {
MySimpleAdapter adapter;
private HashMap<Long, Boolean> positionHide = new HashMap<Long, Boolean>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String[] columns = new String[] { "_id", "name" };
MatrixCursor mc = new MatrixCursor(columns); // cursor for testing
for (int i = 1; i < 35; i++) {
long id = i;
mc.addRow(new Object[] { id, "Name" + i });
}
String[] from = new String[] { "name" };
int[] to = new int[] { R.id.checked_text };
adapter = new MySimpleAdapter(this,
R.layout.adapter_mysimpleadapter_row, mc, from, to);
setListAdapter(adapter);
}
private class MySimpleAdapter extends SimpleCursorAdapter {
public MySimpleAdapter(Context context, int layout, Cursor c,
String[] from, int[] to) {
super(context, layout, c, from, to);
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
super.bindView(view, context, cursor);
CheckedTextView ctv = (CheckedTextView) view
.findViewById(R.id.checked_text);
long pos = cursor.getLong(0); // the id from the cursor
if (positionHide.get(pos) == null) {
ctv.setChecked(false);
// we don't have this id in the hashmap so the value is by
// default false, the TextView is GONE
} else {
// we have the value in the Hashmap so see what it is and set
// the textview visibility from this value
Boolean tmp = positionHide.get(pos);
if (tmp.booleanValue()) {
ctv.setChecked(true);
} else {
ctv.setChecked(false);
}
}
}
}
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
Boolean tmp = positionHide.get(id);
if (tmp == null) {
// if null we don't have this key in the hashmap so
// we add it with the value true
positionHide.put(id, true);
} else {
positionHide.put(id, !tmp.booleanValue());
// if the value exists in the map then inverse it's value
}
adapter.notifyDataSetChanged(); // notify the adapter that something has
// changed
}
}

Getting the _id of the rows in ListVew right

I have a ListView which shows a bunsh of values from a SQLite table. First I used a SimpleCursorAdapter to fill the ListView based on a Cursor from an SQL query. I switched over to using a SimpleAdapter in stead because I had to manipulate/add data in the list before sending it over to the ListView.
Using the SimpleCursorAdapter the id returned from the ListView after tapping a row is the correct ID from the database table, but using a SimpleAdapter the id looks like its just generated by the ListView because it is the same as the position.
My table looks like this:
_id | col1 | col2 | col3
The method producing the cursor for the SimpleCursorAdapter looks like this:
public Cursor fetchDataAsCursor()
{
return db.query("table_name", new String[] { "_id", "col1", "col2"}, null, null, null, null, null);
}
The method filling in the ListView using SimpleCursorAdapter looks like this:
private void simpleFillData()
{
Cursor cursor = dbAdapter.fetchDataAsCursor();
startManagingCursor(cursor);
String[] from = new String[] {"col1", "col2"};
int[] to = new int[] {R.id.col1, R.id.col2};
SimpleCursorAdapter notes = new SimpleCursorAdapter(this,
R.layout.list_row, cursor, from, to);
setListAdapter(notes);
}
This works fine as the id returned is ok in the following method:
protected void onListItemClick(ListView l, View v, int position, long id)
{
super.onListItemClick(l, v, position, id);
Intent i = new Intent(this, DetailActivity.class);
i.putExtra("_id", id);
startActivityForResult(i, ACTIVITY_EDIT);
}
Now switching over to the SimpleAdapter.
The code for producing the List:
public ArrayList<HashMap<String, Object>> getList()
{
ArrayList <HashMap<String, Object>> list = new ArrayList();
c = fetchDataAsCursor();
c.moveToFirst();
for(int i = 0; i < c.getCount(); i++)
{
HashMap<String, Object> h = new HashMap<String, Object>();
h.put("_id", c.getLong(0));
h.put("col1", c.getString(1));
h.put("col2", c.getString(2));
//This is the extra column
h.put("extra", calculateSomeStuff(c.getString(1), c.getString(2));
list.add(h);
c.moveToNext();
}
return list;
}
And then for the method which fills the ListView:
private void fillData()
{
ArrayList<HashMap<String, Object>> list = dbAdapter.getList();
String[] from = new String[] {"col1", "col2", "extra"};
int[] to = new int[] {R.id.col1, R.id.col2, R.id.extra};
SimpleAdapter notes = new SimpleAdapter(this, list, R.layout.list_row, from, to);
setListAdapter(notes);
}
In this last method the ListView failes to pick up the _id value in the list. I would have guessed that it would do this automaticly as it does when using a SimpleCursorAdapter
Is there a way to manipulate the id of a row in a ListView to be sure that it has the same value as the _id key in the database table?
(All code examples is greatly simplified)
Edit:
I figured it out. I had to make my own subclass of SimpleAdapter which overrides public long getItemId(int position)
public class MyListAdapter extends SimpleAdapter
{
private final String ID = "_id";
public PunchListAdapter(Context context, List<? extends Map<String, ?>> data, int resource, String[] from, int[] to)
{
super(context, data, resource, from, to);
}
#Override
public long getItemId(int position)
{
Object o = getItem(position);
long id = position;
if(o instanceof Map)
{
Map m = (Map)o;
if(m.containsKey(ID))
{
o = m.get(ID);
if(o instanceof Long)
id = (Long)o;
}
}
return id;
}
}

That is bad way to work with cursor by using SimpleAdapter. You should implement CursorAdapter.
public class MyCursorAdapter extends CursorAdapter
{
LayoutInflater inflater;
public MyCursorAdapter(Context context, Cursor c) {
super(context, c);
inflater = LayoutInflater.from(context);
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
//cursor is already setted to requared position, just get your column
TextView tv1 = (TextView)view.findViewById(R.id.textView1);
TextView tv2 = (TextView)view.findViewById(R.id.textView2);
tv1.setText(cursor.getString(1));
tv2.setText(cursor.getString(2));
viev.addOnClickListener(new OnClickListener{
public void onClick(View v){
...
cursor.getLong(0);
...
}
});
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
return inflater.inflate(R.layout.my_raw_view, parent, false);
}
}
Than just set adapter to listview in your activity.
Cursor cursor = fetchDataAsCursor();
ListView myListView = (ListView)findViewById(R.id.my_list_view);
myListView.setAdapter(new MyCursorAdapter(this,cursot));

Make listview from SQLite database

I'm trying to populate listview from my SQLite database... this is how I get my data from database:
Cursor c = database.rawQuery("SELECT * FROM " + TableName, null);
int Column1 = c.getColumnIndex("uri");
int Column2 = c.getColumnIndex("file");
int Column3 = c.getColumnIndex("id");
c.moveToFirst();
if (c != null) {
do {
String uri = c.getString(Column1);
String file = c.getString(Column2);
int id = c.getInt(Column3);
} while (c.moveToNext());
}
I would normally add an array to listview like that:
ListView my_listview2 = (ListView) findViewById(R.id.listView1);
String my_array[] = {"Android", "iPhone"};
my_listview2.setAdapter(new ArrayAdapter<String>(this, R.layout.row, R.id.my_custom_row, my_array));
How can I make an array to setadapter from my sql query?

The best way to do this is to use a CursorAdapter or a SimpleCursorAdapter. This will give you the best performance and once you figure it out you'll find it's the simplest approach when using a SQLite db.
http://developer.android.com/reference/android/widget/SimpleCursorAdapter.html
Below is a simple CustomCursorAdapter that I use frequently. Just add the CustomCursorAdapter class as an inner class.
protected class CustomCursorAdapter extends SimpleCursorAdapter {
private int layout;
private LayoutInflater inflater;
private Context context;
public CustomCursorAdapter (Context context, int layout, Cursor c, String[] from, int[] to) {
super(context, layout, c, from, to);
this.layout = layout;
this.context = context;
inflater = LayoutInflater.from(context);
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
Log.i("NewView", newViewCount.toString());
View v = inflater.inflate(R.layout.list_cell, parent, false);
return v;
}
#Override
public void bindView(View v, Context context, Cursor c) {
//1 is the column where you're getting your data from
String name = c.getString(1);
/**
* Next set the name of the entry.
*/
TextView name_text = (TextView) v.findViewById(R.id.textView);
if (name_text != null) {
name_text.setText(name);
}
}
Create an instance of the CustomCursorAdapter like so...
You'll need to create your cursor just like you're already doing.
protected String[] from;
protected int[] to;
//From is the column name in your cursor where you're getting the data
//to is the id of the view it will map to
from = new String[]{"name"};
to = new int[]{R.id.textView};
CustomCursorAdapter adapter = new CustomCursorAdapter(this, R.layout.list, cursor, from, to);
listView.setAdapter(adapter);

I found working with the notepad tutorial very useful for learning about this.
It shows you how to implement the listview using the sqlite database in very easy steps.
http://developer.android.com/resources/tutorials/notepad/index.html

Strange behaviour with custom cursor adapter android

i have been having this issue for some time now, and have not gotten an answer for it yet. i have this custom Cursor adapter which i use to populate a list view from an sqlite database. Now my issue is that i want to populate the listview based on certain conditions.An example is if the condition is important, the listview should display only data that fits into that criteria and so on. I already have working methods that query the database accordingly.
now my problem is that, i can't seem to populate the listviews based on those methods and conditions without:
1) creating a copy of the exact same custom cursor adapter and just changing the names variables.
2) creating a copy of the exact xml layout and changing the id's.
As i say, its working this way, but i feel am having unnecessary classes and xml layout since its exactly the same thing. I know am doing something wrong, i just don't know what. Please any help and explanation would be appreciated. here is the necessary part of the code Code for the CustomCursorAdapter:
public class ViewItems extends ListActivity implements OnItemClickListener{
DBAdapter adapter;
Cursor cursor;
ListView list;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view_list);
adapter = new DBAdapter(this);
adapter.open();
fillData();
list = (ListView)findViewById(android.R.id.list); // default android listView id
list.setOnItemClickListener(this);
}
// Different method calls
protected void fillImportantData() {
Cursor cursor = adapter.retrieveImportant();
startManagingCursor(cursor);
String[] from = new String[]{DBAdapter.NAME, DBAdapter.DATE, DBAdapter.TIME, DBAdapter.PRIORITY};
int[] to = new int[]{R.id.viewNameId, R.id.viewDateId, R.id.viewTimeId};
customCursorAdapter items = new customCursorAdapter(this, R.layout.view_items, cursor, from, to);
setListAdapter(items);
}
public class customCursorAdapter extends SimpleCursorAdapter {
private int layout;
Context context;
public customCursorAdapter(Context context, int layout, Cursor cursor, String[]from, int[] to) {
super(context, layout, cursor, from, to);
this.layout = layout;
this.context = context;
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
ViewHolder holder;
if(view != null){
holder = new ViewHolder();
holder.viewName = (TextView)view.findViewById(R.id.viewNameId);
holder.viewStartDate = (TextView)view.findViewById(R.id.viewDateId);
holder.viewStartTime = (TextView)view.findViewById(R.id.viewTimeId);
view.setTag(holder);
}else{
holder = (ViewHolder)view.getTag();
}
int namecol = cursor.getColumnIndex(DBAdapter.NAME);
String name = cursor.getString(namecol);
if(holder.viewName != null){
holder.viewName.setText(name);
holder.viewName.setTextColor(Color.RED);
}
String startDate = cursor.getString(cursor.getColumnIndex(DBAdapter.DATE));
holder.viewStartDate.setText(startDate);
String startTime = cursor.getString(cursor.getColumnIndex(DBAdapter.TIME));
holder.viewStartTime.setText(startTime);
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(context);
final View view = inflater.inflate(layout, parent, false);
return view;
}
#Override
public long getItemId(int id){
return id;
}
#Override
public Object getItem(int position){
return position;
}
}
static class ViewHolder{
TextView viewName;
TextView viewStartDate;
TextView viewStartTime;
}
}
// methods in database
public Cursor retrieveAll(){
String[] resultColumns = new String[] {KEY_ID, NAME DATE, TIME, PRIORITY};
Cursor cursor = db.query(DATABASE_TABLE, resultColumns, null, , null, null, null);
return cursor;
}
public Cursor retrieveImportant(){
String[] resultColumns = new String[] {KEY_ID, NAME DATE, TIME, PRIORITY};
String[] condition = {"important"};
Cursor cursor = db.query(DATABASE_TABLE, resultColumns, PRIORITY + "=" + "?", condition, null, null, null);
return cursor;
}

If you change the data you wish to display, you will need to run a fresh query on the database and get a Cursor back that reflects that changed data. Depending on the nature of the changes, this may require a fresh CursorAdapter or merely a call to changeCursor(). If the new query returns the same columns and you want them displayed the same way, changeCursor() is probably sufficient. Otherwise, you will need to create a new CursorAdapter and call setAdapter() on your ListView to switch over to it.
You only need a different row layout if you are truly changing the row layout. You do not need to change IDs just for grins. Since you are not doing this in the code you have shown above, I am unclear what specifically you are worried about.