Develop Reference

How to resolve java.lang.StringIndexOutOfBoundsException?

I am getting an error, while calculating on String,
java.lang.StringIndexOutOfBoundsException: length=4; regionStart=5; regionLength=2
My implementation is below.
private void initializeMyPLsAllotted() {
int theMonthWhenICame = Integer.parseInt(myDateHired.substring(5, 7)); //This line is showing the error
int theYearWhenICame = Integer.parseInt(myDateHired.substring(0,4));
int theCurrentMonth = Integer.parseInt(todaysDate.substring(5, 7));
int theCurrentYear = Integer.parseInt(todaysDate.substring(0, 4));
int myTotalMonths = (theCurrentYear - theYearWhenICame)*12 + theCurrentMonth - theMonthWhenICame;
if (myTotalMonths > 6) {
numberOfPLsAllotted = 2;
} else {
numberOfPLsAllotted = 0;
}
myPLs = numberOfPLsAllotted;
}

java.lang.StringIndexOutOfBoundsException: length=4; regionStart=5; regionLength=2
it clearly says that length of your string is 4 and you are trying to fetch sub-string from index 5. make sure your string is valid
you can check something like that to avoid crashing your app
private void initializeMyPLsAllotted() {
if(myDateHired.length() > 7 && todaysDate.length() > 7){
int theMonthWhenICame = Integer.parseInt(myDateHired.substring(5, 7));
int theYearWhenICame = Integer.parseInt(myDateHired.substring(0,4));
int theCurrentMonth = Integer.parseInt(todaysDate.substring(5, 7));
int theCurrentYear = Integer.parseInt(todaysDate.substring(0, 4));
int myTotalMonths = (theCurrentYear - theYearWhenICame)*12 + theCurrentMonth - theMonthWhenICame;
if(myTotalMonths>6) {
numberOfPLsAllotted = 2;
} else {
numberOfPLsAllotted = 0;
}
myPLs = numberOfPLsAllotted;
} else {
// print some error message
}
}

StringIndexOutOfBoundsException means that the section you're trying to substring is outside of the string length.
Example
String test = "123";
String testSubstringOne = test.substring(0, 1);
//testSubstringOne -> "1"
String testSubstringTwo = test.substring(0, 5);
//testSubstringTwo -> java.lang.StringIndexOutOfBoundsException
Make sure your myDateHired has the value you expect.
Tip from the coach
You say that those values are from a server... Maybe you should look into returning data in a more friendly format such as json.

As doc says, the IndexOutOfBoundsException will be throwed when：
if the beginIndex is negative, or endIndex is larger than the length
of this String object, or beginIndex is larger than endIndex
so check myDateHired before using it.

How to Set AlignSpan Style on current cursor paragraph?

I know for set a style into spannable, we can use setSpan(Object classOfStyle, int start, int end, int flags).
I wanna set alignspan into a current paragraph. Current paragraph detected by current cursor position. It`s possible? May i can get start-position and end-position of paragraph?
Edit :
A paragraph is a group of sentences. One of paragraph will be ended by "Enter Character".

I've written a small helper class (optimized for speed) that will do exactly what you want. You pass a Spannable object which will be parsed to find all paragraphs:
public class Layout {
private static final Pattern LINEBREAK_PATTERN = Pattern.compile("\\r\\n|\\r|\\n");
private int mNrOfLines = 0;
private ArrayList<Selection> mSelection = new ArrayList<Selection>();
public Layout(Spannable spannable) {
String s = spannable.toString();
// remove the trailing line feeds
int len = s.length();
char c = len > 0 ? s.charAt(len - 1) : '-';
while (len > 0 && (c == '\n' || c == '\r')) {
len--;
c = s.charAt(len - 1);
}
// now find the line breaks and the according lines / paragraphs
mNrOfLines = 1;
Matcher m = LINEBREAK_PATTERN.matcher(s.substring(0, len));
int groupStart = 0;
while (m.find()) {
mSelection.add( new Selection(groupStart, m.end()) );
groupStart = m.end();
mNrOfLines++;
}
if (groupStart < len) {
mSelection.add( new Selection(groupStart, len) );
}
}
public List<Selection> getParagraphs() {
return mSelection;
}
public int getLineForOffset(int offset) {
int lineNr = 0;
while(lineNr < mNrOfLines && offset >= mSelection.get(lineNr).end()) {
lineNr++;
}
return Math.min(Math.max(0, lineNr), mSelection.size() - 1);
}
public int getLineStart(int line) {
return mNrOfLines == 0 || line < 0 ? 0 :
line<mNrOfLines ? mSelection.get(line).start() :
mSelection.get(mNrOfLines-1).end()-1;
}
public int getLineEnd(int line) {
return mNrOfLines == 0 || line < 0 ? 0 :
line<mNrOfLines ? mSelection.get(line).end() :
mSelection.get(mNrOfLines-1).end()-1;
}
}
The three methods getLineForOffset, getLineStart and getLineEnd can be used to find the paragraphs for the current Selection. The Selection can be either the current cursor position (which is basically a Selection with start==end) or the selected text. The following code will return the selected paragraphs for the current selection:
Selection getParagraphs(EditText editor) {
Layout layout = new Layout( editor.getEditableText() );
int selStart = editor.getSelectionStart();
int selEnd = editor.getSelectionEnd();
int firstLine = layout.getLineForOffset(selStart);
int end = selStart == selEnd ? selEnd : selEnd - 1;
int lastLine = layout.getLineForOffset(end);
return new Selection(layout.getLineStart(firstLine), layout.getLineEnd(lastLine));
}
If e.g. your text is:
line 1
l[ine 2
line ]3
line 4
with everything between the [] selected, getParagraphs() would return the second and third line (it basically expands the selected text to include all (even partially) selected paragraphs.

I Write some method for get first position of paragraph and last position of paragraph.
I don`t know, which one is better performance. Please correct me if its wrong.
public static int getFirstPositionOfParagraph(String paragraph, int cursorPosition) {
StringBuffer buffer = new StringBuffer(paragraph);
List pos = new ArrayList();
for (String breaker : LINE_BREAK){
pos.add(buffer.lastIndexOf(breaker, cursorPosition));
}
int firstPosition = Collections.max(pos);
return firstPosition
public static int getLastPositionOfParagraph(String paragraph, int cursorPosition) {
StringBuffer buffer = new StringBuffer(paragraph);
List pos = new ArrayList();
for (String breaker : LINE_BREAK){
int breakerPos = buffer.indexOf(breaker, cursorPosition);
if (breakerPos > 0)
pos.add(breakerPos);
}
return pos.size() > 0 ? Collections.min(pos) + 1 : paragraph.length();
}

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.

Android: Int stays the same

i feel dumb for asking this but i have been fighting with this for a day now and i can't seem to get it working.
So my problem is I want to keep adding 1 to and integer and make it go like ;
1+1=2
2+1=3
That it keeps updating the Integer I have this now;
int val = 1;
int g = 1;
val = g + val;
But it keeps saying its 2 how come?
Thanks.

I'm guessing you put all of your code in your click handler. Instead, put the variable declaration/initialization in the class level and only your addition code in your click handler. Rough code as follows:
public YourActivity extends Activity {
int val = 1;
int g = 1;
#Override
protected void onCreate (Bundle savedInstanceState) {
... //find button in here
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
val = g + val;
}
});
}
}

Because you keep setting it to 1. Initialize it outside the loop.

int val = 1;
int g = 1;
The next line:
val = g + val;
is therefore equivalent to
val = 1 + 1;
which is equivalent to
val = 2;
Not sure what you would expect here...

int val = 1; int g = 1; val = g + val;
Will always evaluate to 2. Because what happens is you take the value in g which is 1 and the value in val which is 1. This produces the sum of 2. You then take 2 and assign it to the variable val (which previously was initialized to 1).
1+1 will always be 2 (in Integer mathematics)

So my problem is I want to keep adding 1 to and integer and make it go like ;
1+1=2
2+1=3
I'm guessing you want to do something like this, to produce your output a given number of times.
int timesToLoop = 10;
int summedUp = 0;
for (int i=0; i < timesToLoop; i++)
{
summedUp = i + 1;
System.out.println(i + " + " + "1 = " + summedUp);
}

Array access producing unwanted result

I am getting an unusual result when attempting to place a value in an array.
I have an array table[] of a simple class result{ int score, long time, string ID}
Intention is to have a sort of leader board.
My code happily finds the correct place to insert a new score if it is in the top 10.
int ix = 0;
int jx = 10; //
while ( ix < jx )
{
if (points > sTable[ix].points)
{
// score is higher move records down
for (jx = mNumRecords - 1; jx >ix ; jx--)
{
sTable[jx] = sTable[jx -1];
}
//now add new score
sTable[ix].score = score; // all good until here
sTable[ix].time = time;
}
ix++;
}
Problem is that when I try to insert the score using sTable[ix].score = score;
The value gets written to sTable[ix].score and also sTable[ix +1].score.
It is repeatable, it occurs at any value of ix, I have single stepped through the code and as far as I can tell the command only executes once.
Has anyone seen this before?

That because you copied the object reference to the next element in the array. You should copy the values, or create a new object:
Option A:
// score is higher move records down
for (jx = mNumRecords - 1; jx >ix ; jx--)
{
sTable[jx].time = sTable[jx -1].time;
sTable[jx].score = sTable[jx -1].score;
}
//now add new score
sTable[ix].score = score; // all good until here
sTable[ix].time = time;
Option B:
for (jx = mNumRecords - 1; jx >ix ; jx--)
{
sTable[jx] = sTable[jx -1];
}
sTable[ix] = new Result(score, time, ""); // Or however you construct the object