Database Users

Custom ListView adapter repeats itself

I have a custom listview that pulls from an array, however when I reach a point that I have to scroll down to see more items, the items start to repeat themselves. According to the array, the items are fine and not repeating themselves, it looks like it's just the ListAdapter. Any help is greatly appreciated. I think the getView is really the only problem, but if you need other parts of the code, let me know.
Code:
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.list_item, parent, false);
holder = new ViewHolder();
holder.title = (TextView) convertView.findViewById(R.id.row_title);
holder.summary = (TextView) convertView.findViewById(R.id.row_summary);
holder.url = (TextView) convertView.findViewById(R.id.row_link);
convertView.setTag(holder);
String item = CurbAlert.listings[position];
item = item.replace("<br>", "");
String title = item.substring(item.indexOf("<title>") + 16, item.indexOf("</title>") - 3);
String summary = item.substring(item.indexOf("<description>") + 22, item.indexOf("</description>") - 3);
if (summary.length() > 100) { summary = summary.substring(0, 100); summary += "..."; }
holder.title.setText(title);
holder.summary.setText(summary);
holder.url.setText(item.substring(item.indexOf("<link>") + 6, item.indexOf("</link>")));
} else {
holder = (ViewHolder) convertView.getTag();
}
return convertView;
}

Try moving everything from line 10 to 17 inclusive until after the if-else statement. You want to setup the views even if you get your holder from getTag().

How to prevent laggy scrolling ListView w ImageView-Items filled with cached images?

Hello community,
I've got a ListActivity in my app, which shows Views including TextViews, for showing artist, title and album information of some mp3-Files (queried by my cursor), and an ImageView, for showing an albumart => Similar to the Tracklist in the music app.
Here's the code for my custom SimpleCursorAdapter and it's binding to the ListView:
Code:
void setListAdapterOverride() {
String[] fromColumns = new String[] {
AudioColumns.ARTIST,
MediaColumns.TITLE,
AudioColumns.ALBUM,
AudioColumns.ALBUM_ID
};
int[] toColumns = new int[] {
R.id.tv_artist,
R.id.tv_title,
R.id.tv_album,
R.id.iv_albumArt
};
cursorAdapter = new customAdapter(getBaseContext(), R.layout.listviewitem, cursor, fromColumns, toColumns);
setListAdapter(cursorAdapter);
if (MyDebug.Log)
Log.d("Activity", "ListAdapter gesetzt");
}
class customAdapter extends SimpleCursorAdapter {
int layout;
Cursor cursor;
String[] from;
int[] to;
public customAdapter(Context context, int layout, Cursor c,
String[] from, int[] to) {
super(context, layout, c, from, to);
this.layout = layout;
this.cursor = c;
this.from = from;
this.to = to;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
if (row == null) {
LayoutInflater inflater = getLayoutInflater();
row = inflater.inflate(R.layout.listviewitem, parent, false);
if (MyDebug.Log)
Log.d("Activity", "Inflate");
}
cursor.moveToPosition(position);
TextView artist = (TextView) row.findViewById(to[0]);
TextView title = (TextView) row.findViewById(to[1]);
TextView album = (TextView) row.findViewById(to[2]);
ImageView albumArt = (ImageView) row.findViewById(to[3]);
artist.setText(cursor.getString(cursor.getColumnIndex(from[0])));
title.setText(cursor.getString(cursor.getColumnIndex(from[1])));
album.setText(cursor.getString(cursor.getColumnIndex(from[2])));
Cursor albumArtCursor = contentResolver.query(MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI, new String[] { MediaStore.Audio.Albums._ID, MediaStore.Audio.Albums.ALBUM_ART }, MediaStore.Audio.Albums._ID + "='" + cursor.getInt(cursor.getColumnIndex(from[3])) + "'", null, null);
albumArtCursor.moveToFirst();
String albumArtUri = albumArtCursor.getString(albumArtCursor.getColumnIndex(MediaStore.Audio.Albums.ALBUM_ART));
if (albumArtUri == null) albumArtUri = "default";
if (!imageCache.containsKey(albumArtUri)) {
Bitmap albumArtBitmap;
if (!albumArtUri.equals("default")) {
Options opts = new Options();
opts.inJustDecodeBounds = true;
BitmapFactory.decodeFile(albumArtUri, opts);
Integer[] bitmapSize = new Integer[] { opts.outWidth, opts.outHeight };
Integer scaleFactor = 1;
while ((bitmapSize[0]/2 > 50) && (bitmapSize[1]/2 > 50)) {
scaleFactor++;
bitmapSize[0] /= 2;
bitmapSize[1] /= 2;
}
opts = new Options();
opts.inSampleSize = scaleFactor;
albumArtBitmap = BitmapFactory.decodeFile(albumArtUri, opts);
} else {
albumArtBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_mp_song_list);
}
imageCache.put(albumArtUri, albumArtBitmap);
}
albumArt.setImageBitmap(imageCache.get(albumArtUri));
return row;
}
}
imageCache is a Hashmap<String, Bitmap> for caching the Bitmaps, so they don't have to be decoded from file again when they had been cached before.
In a former version of the code, I didn't have the imageCache, so the albumarts were decoded from file everytime a new row has been added. That slowed down ListView-scrolling. By adding the imageCache scrolling in ListView doesn't lag that much as before, but it's lagging a bit sometimes.
Can anyone help me to further optimize my code to completely prevent lagging when I scroll the ListView?
Thanks regards ChemDroid

How do I implement a onscroll Listener to my listview?

I have a large data to load from JSON.
I have implemented a custom list view by following a tutorial, now since the data is huge I want it load as the user scrolls.
This is my LoadRestaurant class code which is inside the main activity.
Code:
class LoadRestaurants extends AsyncTask<String, String, String> {
//Show Progress Dialog
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(SearchAll.this);
pDialog.setMessage("Loading All Restaurants...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
protected String doInBackground(String... arg) {
//building parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
//Getting JSON from URL
String json = jsonParser.makeHttpRequest(URL_RESTAURANT_LIST, "GET", params);
//Log Cat Response Check
Log.d("Areas JSON: ", "> " + json);
try {
restaurants = new JSONArray(json);
if (restaurants != null) {
//loop through all restaurants
for (int i = 0; i < restaurants.length(); i++) {
JSONObject c = restaurants.getJSONObject(i);
//Storing each json object in the variable.
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String location = c.getString(TAG_LOCATION);
String rating = c.getString(TAG_RATING);
//Creating New Hashmap
HashMap<String, String> map = new HashMap<String, String>();
//adding each child node to Hashmap key
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
map.put(TAG_LOCATION, location);
map.put(TAG_RATING, rating);
//adding HashList to ArrayList
restaurant_list.add(map);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
//dismiss the dialog
pDialog.dismiss();
//Updating UI from the Background Thread
runOnUiThread(new Runnable() {
@Override
public void run() {
ListAdapter adapter = new SimpleAdapter(
SearchAll.this, restaurant_list,
R.layout.listview_restaurants, new String[]{
TAG_ID, TAG_NAME, TAG_LOCATION, TAG_RATING}, new int[]{
R.id.login_id, R.id.restaurant_name, R.id.address, R.id.rating});
setListAdapter(adapter);
ListView lv = getListView();
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// Bundle bundle = new Bundle();
Intent intent = new Intent(SearchAll.this, RestaurantProfile.class);
String loginId = ((TextView) view.findViewById(R.id.login_id)).getText().toString();
intent.putExtra("login_id", loginId);
startActivity(intent);
}
});
}
});
}
}
}
I want to load around 20 restaurants and then it auto loads another 20 as soon as user reaches the end of first 20.
There are lots of tutorials online but its confusing to implement.
Please help me out!

The custom ListView, support for automatic loading you can try https://github.com/chrisbanes/Android-PullToRefresh

Starting chronometer with if condition comparing strings

I have an android application that is receiving a string from an arduino via Bluetooth, names the string "data" and displays it by setting a TextView to the string "data". I want a chronometer to start when the incoming string matches a predefined string.
For example:
Code:
if data.equals(startChrono)){
chronometerLeft.setBase(SystemClock.elapsedRealtime());
chronometerLeft.start();
I actually have the arduino sending a "g" and am setting my string goL to be "g" but cannot get the chronometer to start when the g is received. My TextView shows the g. Code is below. I've tried several things and at a loss. Using same code for chronometer.start() with onClickListener with a button works great. I just need it to start the chronometer when i receive a specific string from the arduino.
Code:
beginListenForData();
// text.setText("Bluetooth Opened");
}
void beginListenForData() {
final Handler handler = new Handler();
final byte delimiter = 10; // This is the ASCII code for a newline
// character
stopWorker = false;
readBufferPosition = 0;
readBuffer = new byte[1024];
workerThread = new Thread(new Runnable() {
public void run() {
while (!Thread.currentThread().isInterrupted() && !stopWorker) {
try {
int bytesAvailable = mmInputStream.available();
if (bytesAvailable > 0) {
byte[] packetBytes = new byte[bytesAvailable];
mmInputStream.read(packetBytes);
for (int i = 0; i < bytesAvailable; i++) {
byte b = packetBytes[i];
if (b == delimiter) {
byte[] encodedBytes = new byte[readBufferPosition];
System.arraycopy(readBuffer, 0,
encodedBytes, 0,
encodedBytes.length);
final String data = new String(
encodedBytes, "US-ASCII");
readBufferPosition = 0;
handler.post(new Runnable() {
public void run() {
text.setText(data);
String goL = "g";
String goR = "f";
chronometerLeft = (Chronometer)findViewById(R.id.chronometerLeft);
chronometerRight = (Chronometer)findViewById(R.id.chronometerRight);
if(data.equals(goL)){
chronometerLeft.setBase(SystemClock.elapsedRealtime());
chronometerLeft.start();
if(data.equals(goR))
chronometerRight.setBase(SystemClock.elapsedRealtime());
chronometerRight.start();
}
}
});
} else {
readBuffer[readBufferPosition++] = b;
}
}
}
} catch (IOException ex) {
stopWorker = true;
}
}
}
});
workerThread.start();
}

Sorry to bother, but in your while loop condition, what does the '!' before Thread do?

[Q] Button MaskFilter?

Hi,
I'm trying to apply a Mask or Blur Filter to some buttons at runtime... This button is reflecting a "layer" object, so I'd like to blur its edges to reflect how transparent is this layer...
I'm able to set a ColorFilter, or apply a maskFIlter to its TextView, but cant figure how to apply a maskFilter to the whole button...
here is the part of my code where I'd like to apply this filter (in a applyFilter method):
Code:
public void createList(LinearLayout lm) {
lm.removeAllViews();
for (int i = 0; i < kwang07Android.nblayers; i++) {
final Button newbtn = new Button(this, null, android.R.attr.buttonStyleSmall);
int col = kwang07Android.layers[i].col;
int newColor = Color.argb(156+(int)(kwang07Android.layers[i].opacite*100), Color.red(col), Color.green(col), Color.blue(col));
newbtn.getBackground().setColorFilter(newColor, MULTIPLY);
[COLOR="DarkOrange"]//applyFilter(newbtn, i, BlurMaskFilter.Blur.INNER);[/COLOR]
newbtn.setText("couche " + Integer.toString(i));
newbtn.setId(i);
newbtn.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,30+kwang07Android.layers[i].thickness/20));
final int finalI = i;
newbtn.setOnTouchListener(new Button.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
showColorPickerDialogDemo(newbtn, finalI);
}
return false;
}
});
lm.addView(newbtn);
}
...
Any advice?
Thanks.