UITableView Search Controller & Heading Titles (iPhone OS 3.1)

Question

+More of a continuation from a previous thread to discuss a more specific issue+
→ Ray,
I could never get the Sections project to work. I had checked the code, but it still didn't load.
I had tried taking some code out of the book. The initial problems came in the fact that the book used an NSDictionary, and some dictionary specific code, whereas I'm using an array.
In addition, I had taken some code out of Apple's TableSearch sample project, which, among other things, uses a UISearchDisplayController, which is different from the Sections project.
Basically, for the section headings I'm just interested in grabbing the first character in the person object's name, matching it against existing NSStrings in an array, and if it's a different letter, then adding it to the array. The end result should be similar to the built-in Contacts application, assuming that you don't have a contact for every single letter of the alphabet.
I don't want an index, as that would interfere with the detail disclosure buttons (as per the HIG).
Finally, the table is implemented so that it loads a second view based on an objectAtIndex of indexPath.row. The only issue is that when searching it still references the initial array, and so it displays the wrong second level control. I was thinking of implementing a flag which I could check in tableView:didSelectRowAtIndexPath, but I don't know of any isSearching method or equivalent. As before, I'm using a Search Display Controller instead of merely a search bar, which is what the Sections project uses.
Message was edited by: musicwind95

Answer 1

Ok, here's an edit of your EmployeeViewController class that shows how to implement section headers (Person.m is also included to correct a couple minor memory management problems I noticed, but those have nothing to do with our main topic):
// EmployeesViewController.h
#import <UIKit/UIKit.h>
@interface EmployeesViewController : UITableViewController <UISearchDisplayDelegate, UISearchBarDelegate> {
NSArray *initArray; // <-- added master data array
NSDictionary *listContent; // Master data content <-- changed to dictionary
NSDictionary *filteredListContent; // Filtered content as a result of a search <-- changed to dictionary
// The saved state of the search in case of a memory warning
NSString *savedSearchTerm;
BOOL searchWasActive;
BOOL searchIsActive;
// NSString *employeeName;
@property (nonatomic, retain) NSArray *initArray; // <-- added master data array
@property (nonatomic, retain) NSDictionary *listContent; // <-- changed to dictionary
@property (nonatomic, retain) NSDictionary *filteredListContent; // <-- changed to dictionary
@property (nonatomic, copy) NSString *savedSearchTerm;
@property (nonatomic) BOOL searchWasActive;
@property (nonatomic) BOOL searchIsActive;
@end
// EmployeesViewController.m
#import "EmployeesViewController.h"
// #import "NSDictionary-MutableDeepCopy.h" <-- not needed
#import "Person.h"
// #import "Constants.h" <-- not needed
#import "EmployeesDetailController.h"
// #import "EmployeeJobsController.h" <-- not needed
@implementation EmployeesViewController
@synthesize initArray; // <-- added master data array
@synthesize listContent;
@synthesize filteredListContent;
@synthesize savedSearchTerm;
@synthesize searchWasActive;
@synthesize searchIsActive;
#pragma mark -
#pragma mark Custom Methods
// --> added helper method to handle openURL:tel: failure
- (void)openTelURLFailed:(Person*)person {
NSString *device = [UIDevice currentDevice].model;
NSLog(@"Call could not be successfully opened. This device is an %@", device);
// TODO: Does this message comply with HIG? If user can't do anything, why display the alert?
// --> It's correct to let the user know why the call failed and ask the user to acknowledge this
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Could not open Phone application"
message:[NSString stringWithFormat:
@"The phone call to %@
could not be placed because your %@ does not have a Phone application.",
[person employeeName], [person telephoneNumber], device]
delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
[alert release];
// --> added helper method to make alphabetic dictionary from sorted array of Person objects
- (NSDictionary)getDictionaryFromArray:(NSArray)personArray {
NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithCapacity:26];
for (Person *p in personArray) {
// get the first initial of employeeName as an uppercase string
NSString *name = [p.employeeName capitalizedString];
if (![name length]) continue;
NSString *initial = [name substringToIndex:1];
NSMutableArray *array = [dict objectForKey:initial];
if (array == nil) {
// add new key-array pair to the dictionary
array = [NSMutableArray arrayWithCapacity:[personArray count]];
[dict setObject:array forKey:initial];
// add current Person object to the array for first initial of name
[array addObject:p];
return [NSDictionary dictionaryWithDictionary:dict];
// --> added helper method to get the array of Person objects for a given table and section no.
- (NSArray)getListForTableView:(UITableView)tableView section:(NSUInteger)section {
NSDictionary *dict = tableView == self.searchDisplayController.searchResultsTableView ? filteredListContent : listContent;
NSString *key = [[[dict allKeys] sortedArrayUsingSelector:@selector(compare:)] objectAtIndex:section];
return [dict objectForKey:key];
#pragma mark -
#pragma mark Lifecycle Methods
- (void)viewDidLoad {
// Create dummy data set --> start abbreviated code block
NSArray *jobs = [[NSArray alloc] initWithObjects: // ...
NSArray *alex = [[NSArray alloc] initWithObjects: // ...
NSArray *turner = [[NSArray alloc] initWithObjects: // ...
NSArray *initContents = [[NSArray alloc] initWithObjects:
[Person personWithContentsOfArray:alex],
[Person personWithContentsOfArray:turner],
nil];
self.initArray = initContents; // <-- save master data array
self.listContent = [self getDictionaryFromArray:initArray]; // <-- dictionary
[alex release];
[turner release];
// --> end abbreviated code block - all other code in this file may be copied verbatim
[jobs release];
[initContents release];
// Create a filtered list that will contain products for the search results table <-- not needed here
// Restore search settings if previously saved
if (self.savedSearchTerm){
[self.searchDisplayController setActive:self.searchWasActive];
[self.searchDisplayController.searchBar setText:savedSearchTerm];
self.savedSearchTerm = nil;
[self.tableView reloadData];
self.tableView.scrollEnabled = YES;
self.searchIsActive = NO;
- (void)viewDidUnload {
self.filteredListContent = nil;
self.searchIsActive = NO;
- (void)viewDidDisappear:(BOOL)animated {
// Save the state of the search
self.searchWasActive = [self.searchDisplayController isActive];
self.savedSearchTerm = [self.searchDisplayController.searchBar text];
self.searchIsActive = NO;
- (void)dealloc {
[savedSearchTerm release]; // <-- release retained string
[listContent release];
[filteredListContent release];
[initArray release]; // <-- release master data array
[super dealloc];
#pragma mark -
#pragma mark UITableView data source and delegate methods
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
NSDictionary *dict = tableView == self.searchDisplayController.searchResultsTableView ? filteredListContent : listContent; // <-- get dictionary
return [[dict allKeys] count]; // <-- return number of keys in dictionary
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// If the requested table view is the search controller's view, return the count of the filtered list; otherwise, return the count of the main list
NSArray *list = [self getListForTableView:tableView section:section]; // <-- get array for section
return [list count]; // <-- return row count for section
// --> added to implement section headers
- (NSString)tableView:(UITableView)tableView titleForHeaderInSection:(NSInteger)section {
NSDictionary *dict = tableView == self.searchDisplayController.searchResultsTableView ? filteredListContent : listContent;
NSArray *allKeys = [dict allKeys];
if ([allKeys count] == 0)
return @"";
return [[allKeys sortedArrayUsingSelector:@selector(compare:)] objectAtIndex:section];
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *kCellID = @"cellID";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:kCellID];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:kCellID] autorelease];
cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
// If the requesting table view is the search controller's table, configure the cell using the filtered content; otherwise, use the main list
NSArray *list = [self getListForTableView:tableView section:indexPath.section]; // <-- get array for section
Person *person = [list objectAtIndex:indexPath.row]; // <-- get person for row
cell.textLabel.text = person.employeeName;
cell.detailTextLabel.text = person.telephoneNumber;
return cell;
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSLog (@"searchIsActive: %d", self.searchIsActive); // <-- %d
// if (self.searchIsActive == NO) { // <-- = > -- }
// rewrite to consolidate code:
NSArray *list = [self getListForTableView:tableView section:indexPath.section]; // <-- get array for section
Person *person = [list objectAtIndex:indexPath.row];
NSString *phoneNumberToDial = [NSString stringWithFormat:@"tel:%@", [person telephoneNumber]];
NSURL *callURL = [[NSURL alloc] initWithString:phoneNumberToDial];
if ([[UIApplication sharedApplication] openURL:callURL])
NSLog(@"Call initialized properly.");
else
[self openTelURLFailed:person];
[callURL release];
- (void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath {
NSArray *list = [self getListForTableView:tableView section:indexPath.section]; // <-- get array for section
EmployeesDetailController *detailView = [[EmployeesDetailController alloc] dataFromPerson:[list objectAtIndex:indexPath.row]]; // <--
[self.navigationController pushViewController:detailView animated:YES];
[detailView release]; // <-- uncomment
#pragma mark -
#pragma mark Content Filtering
- (void)filterContentForSearchText:(NSString *)searchText {
// Update the filtered array based on the search text and scope
// Clear the filtered array <-- the filtered array is now local
NSMutableArray *filteredArray = [NSMutableArray arrayWithCapacity:[self.initArray count]];
// Search the main list for products whose name matches searchText, and add matching items to the filtered array
for (Person *person in initArray) { // <-- traverse the master data array
NSComparisonResult resultName = [person.employeeName compare:searchText options:(NSCaseInsensitiveSearch | NSDiacriticInsensitiveSearch) range:NSMakeRange(0, [searchText length])];
NSComparisonResult resultPhone = [person.telephoneNumber compare:searchText options:(NSCaseInsensitiveSearch | NSDiacriticInsensitiveSearch) range:NSMakeRange(0, [searchText length])];
if (resultName == NSOrderedSame || resultPhone == NSOrderedSame) {
[filteredArray addObject:person];
self.filteredListContent = [self getDictionaryFromArray:filteredArray]; // <-- get filtered dictionary from filtered array
self.searchIsActive = YES;
#pragma mark -
#pragma mark UISearchDisplayController Delegate Methods
- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {
[self filterContentForSearchText:searchString];
self.searchIsActive = YES;
// Return YES to force the table view to be reloaded
return YES;
- (void)searchDisplayControllerDidBeginSearch:(UISearchDisplayController *)controller {
self.searchIsActive = YES;
@end
// Person.m
#import "Person.h"
@implementation Person
+(id)personWithContentsOfArray:(NSArray *)initArray {
Person *myPerson = [[[Person alloc] init] autorelease]; // <-- convenience method should autorelease
return myPerson;
- (void)dealloc { // <-- release all retained ivars
[employeeName release];
[telephoneNumber release];
[employeeEmail release];
[employeeJobs release];
[super dealloc];
@end
The above doesn't do anything about saving or retrieving persistent data. Instead of using the plist structure described previously, the example just converts your dummy array to a dictionary. I decided not to replace the dummy array with a more natural structure after giving some thought to where the overall app might be headed. Considering the Employee section in isolation, the plist is a natural fit. But the finance tab tells us you're probably going to need a database. If that's the case the dummy array might as well stay in place until we know more about the overall data requirements (I can only hope you haven't promised anyone a one-off iPhone port of QuickBooks for Father's Day).
- Ray