Develop Reference

load text from String array and set text to textview is very slow in big string array

hi
why load text from String array and set text to textview is very slow in big string array?
please help to me.
//get khotbe text from database and copy to khotbe activity
private void setkhotbetextarabicfarsi() {
this.sqliteDB = SQLiteDatabase.openOrCreateDatabase(this.getDatabasePath("aliname").getPath(), (SQLiteDatabase.CursorFactory) null);
Itemid = this.getIntent().getIntExtra("selectedFromListid", 1);
Cursor cursorLines = this.sqliteDB.rawQuery("SELECT * FROM khotbe where IDFehrest=" + this.Itemid , (String[]) null);
allrecs = cursorLines.getCount();
matn = new String[allrecs];
if (this.allrecs != 0) {
cursorLines.moveToFirst();
for (int i = 0; i < this.allrecs; ++i) {
String TextArabicOfKhotbe = cursorLines.getString(cursorLines.getColumnIndex("TextArabicOfKhotbe"));
int IDkhotbe = cursorLines.getInt(cursorLines.getColumnIndex("IDkhotbe"));
this.matn[i] = TextArabicOfKhotbe;
cursorLines.moveToNext();
}
}
and main code:
for(int var1 = 0; var1 < this.allrecs; ++var1) {
tvArabic = new JustifiedTextView(this);
tvArabic.setText(matn[var1]);

you are creating the textviews in loop that might making it slow.. try populating the array values using an adapter..
Also check the number of rows you are accessing from the DB. if they are huge in number, they would require more time to be fetched.
Use limit in that case.

NumberFormatException Invalid Long with Calendar

I am having problems with this NumberFormatException Invalid Long. The log cat is showing that the error is coming from the Long.parseLong part of the method.
public static String getDateTimeStr(String p_time_in_millis) {
SimpleDateFormat sdf = new SimpleDateFormat(DATE_TIME_FORMAT);
Date l_time = new Date(Long.parseLong(p_time_in_millis));
return sdf.format(l_time);
}
Can someone tell me why this code works fine when I fetch and display the data in certain calendars then in other calendars on my device I get this NumberFormatException Invalid Long please?
Edit: Here is the rest of the code…
private void getEvents() {
Uri l_eventUri;
ArrayList<Map<String, String>> allStudents = new ArrayList<Map<String, String>>();
if (Build.VERSION.SDK_INT >= 8) {
l_eventUri = Uri.parse("content://com.android.calendar/events");
} else {
l_eventUri = Uri.parse("content://calendar/events");
}
String[] l_projection = new String[]{"title", "dtstart", "dtend"};
#SuppressWarnings("deprecation")
Cursor l_managedCursor = this.managedQuery(l_eventUri, l_projection, "calendar_id=" + m_selectedCalendarId, null, "dtstart DESC, dtend DESC");
if (l_managedCursor.moveToFirst()) {
int l_colTitle = l_managedCursor.getColumnIndex(l_projection[0]);
int l_colBegin = l_managedCursor.getColumnIndex(l_projection[1]);
int l_colEnd = l_managedCursor.getColumnIndex(l_projection[2]);
String l_title = String.valueOf(l_colTitle);
String l_begin = Integer.toString(l_colBegin);
String l_end = Integer.toString(l_colEnd);
do {
Map<String, String> map = new HashMap<String, String>();
l_title = l_managedCursor.getString(l_colTitle);
l_begin = getDateTimeStr(l_managedCursor.getString(l_colBegin));
l_end = getDateTimeStr(l_managedCursor.getString(l_colEnd));
map.put("eventTitles", l_title);
map.put("event_begin", l_begin);
map.put("event_end", l_end);
allStudents.add(map);
} while (l_managedCursor.moveToNext());
l_managedCursor.close();
SimpleAdapter adapter = new SimpleAdapter(this, allStudents, R.layout.notice_layout, new String[] { "eventTitles", "event_begin", "event_end" }, new int[] { R.id.tvTitle, R.id.tvBody, R.id.tvTeacherCode});
listViewCalendar.setAdapter(adapter);
}
}
Edit 2:
For some reason the code works fine without this line of code so I've nailed it down to this line of code.
l_end = getDateTimeStr(l_managedCursor.getString(l_colEnd));
Why does the l_colEnd get caught up in an NumberFormatExcetion? When the following line of code could be also caught up in the same NumberFormatException because it is enquiring about the same int format?
l_begin = getDateTimeStr(l_managedCursor.getString(l_colBegin));
Thank you too all who have helped. The other interesting thing also is when I add this
int l_cnt = 0;
do {
++l_cnt;
} while (l_managedCursor.moveToNext() && l_cnt < 100);
to the while clause as shown below at the end of the following code the app works fine with no lines of code throwing a NumberFormatException..
if (l_managedCursor.moveToFirst()) {
int l_cnt = 0;
int l_colTitle = l_managedCursor.getColumnIndex(l_projection[0]);
int l_colBegin = l_managedCursor.getColumnIndex(l_projection[1]);
int l_colEnd = l_managedCursor.getColumnIndex(l_projection[2]);
String l_title = String.valueOf(l_colTitle);
String l_begin = Integer.toString(l_colBegin);
String l_end = Integer.toString(l_colEnd);
do {
Map<String, String> map = new HashMap<String, String>();
l_title = l_managedCursor.getString(l_colTitle);
l_begin = getDateTimeStr(l_managedCursor.getString(l_colBegin));
l_end = getDateTimeStr(l_managedCursor.getString(l_colEnd));
map.put("eventTitles", l_title);
map.put("event_begin", l_begin);
map.put("event_end", l_end);
allStudents.add(map);
++l_cnt;
} while (l_managedCursor.moveToNext() && l_cnt < 100);

Can someone tell me why this code works fine when I fetch and display
the data in certain calendars then in other calendars on my device I
get this NumberFormatException Invalid Long please?
Date l_time = new Date(Long.parseLong(p_time_in_millis));
IMO. This code is "bad" code.
Why? You try to fetch unknown data from unchecked sources
"content://com.android.calendar/events" and "content://calendar/events"
Almost everybody can access calendars and save whatever he like... Sadly there is no rule there for using this! So making a wild guess an app is using this event column to save data in another that your expected format.
Regarding the check l_cnt < 100, where fail stops
It's not failing because the error happens to 101 event or later!
My solution would to check my data, and never trust that other apps will act as I expected or as they should.
So I suggest to change getDateTimeStr method as follows:
public static String getDateTimeStr(String p_time_in_millis) {
SimpleDateFormat sdf = new SimpleDateFormat(DATE_TIME_FORMAT);
long timestamp = 0;
try {
timestamp = Long.parseLong(p_time_in_millis)
} catch(NumberFormatException e) {
Log.w("getDateTimeStr", "Cannot convert '"+p_time_in_millis+"' to long");
e.printStackTrace(); // Prints full error exception
}
Date l_time = new Date(timestamp);
return sdf.format(l_time);
}
Remove the l_cnt < 100 check and leave the code to run checking your logcat! You will now have a better overview of what is happening and also your bad data dates will be 1/1/1970 (due to 0 timestamp) code can be changed responsively in order to handle that dates which does not have the expected format.
Some ideas for handling errors:
Make getDateTimeStr throw an exception to the getEvents() which could catch it and ignore the event with the unexpected data. (Handling logic, ignoring what I cannot understand.)
Recognize the format of the p_time_in_millis in each different case and use different DATE_TIME_FORMAT types regarding the exact format of each event. Okey, that's needs a lot of investigation and still can fail. Also you have to add the case that the format is still unknown so maybe ignore it or use a default value in order not to crash.
Generally, you always try to write a stable app that will not fail if another app saves data in a different format (because it like so or due to its own bug)

I want to get random data without repeat

I want to get random data from database(sqlite) without repeat.Can anyone help me ..
DBManager *databaseManager = (DBManager *)[[DBManager alloc] init];
NSArray *array=[databaseManager readQuestionFromDatabase];
que=[array objectAtIndex:0];
self.lblQuestion.text=que.question;
[self.btnOption1 setTitle:que.questionoption1 forState:UIControlStateNormal];
[self.btnOption2 setTitle:que.questionoption2 forState:UIControlStateNormal];
[self.btnOption3 setTitle:que.questionoption3 forState:UIControlStateNormal];
[self.btnOption4 setTitle:que.questionoption4 forState:UIControlStateNormal];

This is another answer which uses same random number generation without repetition but avoids multiple query execution.
String randomRowData = "";
selQuery = "SELECT MYFIELD FROM MYTABLE ";
ArrayList<String> list = new ArrayList<Integer>(size);
for(int i = 1; i <= size; i++) {
list.add(MYFIELD_VALUE); // All DB Data here
}
Random rand = new Random();
while(list.size() > 0) {
int index = rand.nextInt(list.size());
randomRowData = list.remove(index); // Will display the rows without repetition
/* USE THE ROW DATA APPROPRIATELY */
}

This approach using Random Number Generation via java and ROWNUM for SQLITE should help you. But you might have to execute queries multiple times.
int DBSize = getDBSize();
int randomRowNum = 0;
ArrayList<Integer> list = new ArrayList<Integer>(size);
for(int i = 1; i <= size; i++) {
list.add(i);
}
Random rand = new Random();
while(list.size() > 0) {
int index = rand.nextInt(list.size());
randomRowNum = list.remove(index);
selQuery = "SELECT * FROM MYTABLE WHERE ROWNUM = " + randomRowNum + " ORDER BY SOME_UNIQUE_SORT_ORDER";
// EXECUTE SELECT QUERY AND YOU WOULD GET RANDOM ROWS here.
}
private int getDBSize ()
{
int retVal = 5;
retVal = // Select count(1) from myTable;
return retVal; //(Assuming I have 5 records in DB)
}
Note: Make sure your sort order in ORDER BY is unique. Else results would not be as expected.

I'm making a simple Dashclock Calendar extension, and it stopped updating

I'm making a basic Dashclock extension that polls CalendarContract.Events for a list of all calendar events synced to the user's device, retrieve the one that's scheduled to happen the soonest, and post the time, title, location, and desctiption. Here's my code:
public class FullCalService extends DashClockExtension {
public static final String[] FIELDS = { Events._ID, Events.TITLE,
Events.ALL_DAY, Events.EVENT_LOCATION, Events.DTSTART,
Events.EVENT_TIMEZONE, Events.DESCRIPTION };
public FullCalService() {
}
#Override
protected void onUpdateData(int arg0) {
TimeZone tz = TimeZone.getDefault();
long currentTimeMillis = Calendar.getInstance().getTimeInMillis() - tz.getRawOffset();
SharedPreferences prefs = PreferenceManager
.getDefaultSharedPreferences(this);
Cursor c;
if (prefs.getBoolean("allDayAllowed", false)) {
c = getContentResolver().query(
Events.CONTENT_URI,
FIELDS,
new StringBuilder().append("(").append(Events.DTSTART)
.append(" >= ?)").toString(),
new String[] { Long.toString(currentTimeMillis) },
Events.DTSTART, null);
} else {
c = getContentResolver().query(
Events.CONTENT_URI,
FIELDS,
new StringBuilder().append("((").append(Events.ALL_DAY)
.append("= ?) AND (").append(Events.DTSTART)
.append(" >= ?))").toString(),
new String[] { Integer.toString(0),
Long.toString(currentTimeMillis) }, Events.DTSTART,
null);
}
if (c.moveToFirst()) {
long eventTimeMillis = c.getLong(c.getColumnIndex(Events.DTSTART));
// if (tz.inDaylightTime(new Date(eventTimeMillis))) {
// eventTimeMillis += tz.getDSTSavings();
// }
//Log.d("DesCal service", "Value of hoursToReveal: "+prefs.getString("hoursToReveal", "1"));
if (eventTimeMillis < currentTimeMillis + 360000
* Integer.parseInt(prefs.getString("hoursToReveal", "1"))) {
String title = c.getString(c.getColumnIndex(Events.TITLE));
String loc = c.getString(c
.getColumnIndex(Events.EVENT_LOCATION));
String time = DateUtils.formatDateTime(this, eventTimeMillis,
DateUtils.FORMAT_SHOW_TIME);
String desc = c.getString(c.getColumnIndex(Events.DESCRIPTION));
StringBuilder expandedBody = new StringBuilder(time);
if (!loc.isEmpty()){
expandedBody.append(" - ").append(loc);
}
expandedBody.append("\n").append(desc);
String uri = new StringBuilder(
"content://com.android.calendar/events/").append(
c.getLong(c.getColumnIndex(Events._ID))).toString();
publishUpdate(new ExtensionData()
.visible(true)
.status(time)
.expandedTitle(title)
.expandedBody(expandedBody.toString())
.icon(R.drawable.ic_dash_cal)
.clickIntent(
new Intent(Intent.ACTION_VIEW, Uri.parse(uri))));
c.close();
} else {
publishUpdate(new ExtensionData().visible(false));
c.close();
}
} else {
publishUpdate(new ExtensionData().visible(false));
c.close();
}
}
}
Upon first install, it appeared to work just fine. However, after the event began, it would not grab any future events. Is there a reason why the extension will not refresh itself?

How are you triggering further updates? You need to manually specify when you'd like to have onUpdateData called, e.g. when there's a change to a content provider, or when the screen turns on, etc. Extensions by default refresh only every 30 minutes or so. See the source for the built in calendar extension for example code.

Indexing Android

My problem is I have around 1000+ records in an Android App
string field1;
string field2;
string field3;
string field4;
//...
I want to search in this set of records and get the best results on two fields (field1 and field2).
Currently I read each record and compare() (string compare) with the text i want to search so that takes a long time.
What is the best method to perform search?
Store each records in SQLite DB and do "select query where like"
Hash-Mapped
? any other suggestions?
Or may be create an Index of the records and do search.

If you want to search for not exact matches, I would try to make an ArrayList of MyAppRecord where
public class MyAppRecord {
private String record;
private int deviance;
}
and get for each record the deviance of the String you want to find with:
public static int getLevenshteinDistance (String s, String t) {
if (s == null || t == null) {
throw new IllegalArgumentException("Strings must not be null");
}
int n = s.length(); // length of s
int m = t.length(); // length of t
if (n == 0) {
return m;
} else if (m == 0) {
return n;
}
int p[] = new int[n+1]; //'previous' cost array, horizontally
int d[] = new int[n+1]; // cost array, horizontally
int _d[]; //placeholder to assist in swapping p and d
// indexes into strings s and t
int i; // iterates through s
int j; // iterates through t
char t_j; // jth character of t
int cost; // cost
for (i = 0; i<=n; i++) {
p[i] = i;
}
for (j = 1; j<=m; j++) {
t_j = t.charAt(j-1);
d[0] = j;
for (i=1; i<=n; i++) {
cost = s.charAt(i-1)==t_j ? 0 : 1;
// minimum of cell to the left+1, to the top+1, diagonally left and up +cost
d[i] = Math.min(Math.min(d[i-1]+1, p[i]+1), p[i-1]+cost);
}
// copy current distance counts to 'previous row' distance counts
_d = p;
p = d;
d = _d;
}
// our last action in the above loop was to switch d and p, so p now
// actually has the most recent cost counts
return p[n];
}
}
save it to your MyAppRecord-object and finally sort your ArrayList by the deviance of its MyAppRecord-objects.
Note that this could take some time, depending on your set of records. And NOTE that there is no way of telling wether dogA or dogB is on a certain position in your list by searching for dog.
Read up on the Levensthein distance to get a feeling on how it works. You may get the idea of sorting out strings that are possibly to long/short to get a distance that is okay for a threshold you may have.
It is also possible to copy "good enough" results to a different ArrayList.