how reload table view content depend on segment index - iphone

Question

i went table view change content depend on SegmentIndex
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
}
// Set up the cell
book *bok = (book *)[self.booktable objectAtIndex:indexPath.row];
NSArray *rowoftitle = [NSArray arrayWithObjects:bok.book_title, nil];
NSArray *rowofauth = [NSArray arrayWithObjects:bok.author_name, nil];
NSArray *rowofpub = [NSArray arrayWithObjects:bok.pub_name, nil];
//[cell setText:bok.book_title];
[tableView beginUpdates];
switch (segControl.selectedSegmentIndex)
{
case 0:
[tableView insertRowsAtIndexPaths:rowoftitle withRowAnimation:UITableViewRowAnimationTop];
//cell.textLabel.text =bok.book_title;
break;
case 1:
[tableView insertRowsAtIndexPaths:rowofauth withRowAnimation:UITableViewRowAnimationTop];
//[libraryTV reloadData];
//cell.textLabel.text =bok.author_name;
break;
case 2:
[tableView insertRowsAtIndexPaths:rowofpub withRowAnimation:UITableViewRowAnimationTop];
//cell.textLabel.text =bok.pub_name;
break;
default:
break;
}
[tableView endUpdates];
//return cell;
}
but when run it the expiation is happen :
'NSInvalidArgumentException', reason: '-[NSCFString row]: unrecognized
selector sent to instance 0x5d84f80
how resolve it.

Answer 1

One solution could be:
You will need to use a common datasource (in this code I am using dataSourceArray for this purpose, you will need to declare it in header file and alloc/init in viewDidLoad method.), which will be updated on changing the segment.
It will have following method.(for segment change event)
-(void)segmentSelected:(UISegmentedControl *)sender
{
switch (sender.selectedSegmentIndex)
{
case 0:
[self loadTitles];
break;
case 1:
[self loadAuthors];
break;
case 2:
[self loadPublishers];
break;
default:
break;
}
}
- (void) loadTitles
{
[self.dataSourceArray removeAllObjects];
for (Book *book in self.booktable)
{
[dataSourceArray addObject:book.book_title];
}
[<yourTableViewVariable> reloadData];
}
Similarly code for other methods loadAuthors and loadPublishers.
Now your numberOfRowsInSection method will be:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [dataSourceArray count];
}
and cellForRowAtIndexPath will be:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
}
// Set up the cell
cell.textLabel.text = [dataSourceArray objectAtIndex:indexPath.row];
return cell;
}
Thanks

Answer 2

Changing content means setting properties of the cell from your data source based on the section. That's normal and Apple's docs on how to implement a UITableViewController cover it well. What you are doing is attempting to modify the structure of the table while the table is reloading. You absolutely cannot do that.
The table modification methods (e.g. insertRowsAtIndexPaths:withRowAnimation:) are meant to be called after you've modified the data model and want to update the table dynamically w/o reloading the entire table. These cannot be called inside any method used to construct the table or cells. tableView:cellForRowAtIndexPath: will end up being called by insertRowsAtIndePaths:... to construct the cells for the new rows.

Answer 3

in interface :
NSMutableArray *booktable;
NSMutableArray *sbook;
NSMutableArray *rowoflibrary;
NSString *databaseName;
NSString *databasePath;
IBOutlet UISegmentedControl *segControl;
IBOutlet UITableView *libraryTV;
IBOutlet UISearchBar *searchBar;
in implementation
- (void)viewDidLoad {
databaseName = #"MydataBase.db";
// Get the path to the documents directory and append the databaseName
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
// Execute the "checkAndCreateDatabase" function
[self checkAndCreateDatabase];
[self readbookFromDatabase];
booktable = [[NSMutableArray alloc]init];
[booktable addObjectsFromArray:sbook];
rowoflibrary = [[NSMutableArray alloc] init];
[super viewDidLoad];}
-(void) checkAndCreateDatabase{
// Check if the SQL database has already been saved to the users phone, if not then copy it over
BOOL success;
// Create a FileManager object, we will use this to check the status
// of the database and to copy it over if required
NSFileManager *fileManager = [NSFileManager defaultManager];
// Check if the database has already been created in the users filesystem
success = [fileManager fileExistsAtPath:databasePath];
// If the database already exists then return without doing anything
if(success) return;
// If not then proceed to copy the database from the application to the users filesystem
// Get the path to the database in the application package
NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:databaseName];
// Copy the database from the package to the users filesystem
[fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];
[fileManager release];}
-(void) readbookFromDatabase {
// Setup the database object
sqlite3 *database;
// Init the staff Array
sbook = [[NSMutableArray alloc] init];
// Open the database from the users filessytem
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
// Setup the SQL Statement and compile it for faster access
const char *sqlStatement ="select book.title,author.auth_name ,publisher.pub_name , book.info from book ,author, publisher where book.auth_id = author.auth_id and book.pub_id = publisher.pub_id";
sqlite3_stmt *compiledStatement;
if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
// Loop through the results and add them to the feeds array
while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
// Read the data from the result row
char * str = (char*)sqlite3_column_text(compiledStatement, 0);
if (str){
title = [NSString stringWithUTF8String:str];
}
else{
title =#" ";
}
char * str1 = (char*)sqlite3_column_text(compiledStatement, 1);
if (str1){
authorName = [NSString stringWithUTF8String:str1];
}
else{
authorName =#" ";
}
char * str2 = (char*)sqlite3_column_text(compiledStatement, 2);
if (str2){
pubName = [NSString stringWithUTF8String:str2];
}
else{
pubName =#" ";
}
char * str3 = (char*)sqlite3_column_text(compiledStatement,3);
if (str3){
info = [NSString stringWithUTF8String:str3];
}
else{
info =#" ";
}
// Create a new book object with the data from the database
book *bok = [[book alloc] initWithbook:title autname:authorName pubname:pubName infobook:info];
// Add the book object to the staff Array
[sbook addObject:bok];
[bok release];
}
}
// Release the compiled statement from memory
sqlite3_finalize(compiledStatement);
}
sqlite3_close(database);}
-(void)segmentSelected:(UISegmentedControl *)sender{
switch (sender.selectedSegmentIndex) {
case 0:
[self loadTitles];
break;
case 1:
[self loadAuthors];
break;
case 2:
[self loadPublishers];
break;
default:
break; }}
- (void) loadTitles
{
[rowoflibrary removeAllObjects];
for (book *bok in self.booktable)
{
[rowoflibrary addObject:bok.book_title];
}
[libraryTV reloadData];
}
(void) loadAuthors
{
[rowoflibrary removeAllObjects];
for (book *bok in self.booktable)
{
[rowoflibrary addObject:bok.author_name];
}
[libraryTV reloadData];
}
(void) loadPublishers
{
[rowoflibrary removeAllObjects];
for (book *bok in self.booktable)
{
[rowoflibrary addObject:bok.pub_name];
}
[libraryTV reloadData];
}
pragma mark -
pragma mark Table view data source
(NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section {
return [rowoflibrary count];
}
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
}
// Set up the cell
cell.textLabel.text = [rowoflibrary objectAtIndex:indexPath.row];
return cell;
}
when run it it is empty table view