StackOverflow2013

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POSort TableView by distance from current location
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copied!<p>I have an SQL DB that contains Lat and Long info. I have found my current location and been able to get the distance of each location from my current location. I can get my tableview to show this distance, but know I want to sort that tableview so the closest are listed first.</p> <p>My thought is I will need to add the distance to my SQL DB data, sort that some how and then display that info back to the tableview.</p> <p>My thought is I would do all of this within my TableView. Looking for guidance on how to do this and if I should be doing it in the tableview.</p> <pre><code>#import "TulsaMasterViewController.h" #import "TulsaDetailViewController.h" #import "Bars.h" #import "BarDatabase.h" @implementation TulsaMasterViewController @synthesize barArray = _barArray; @synthesize currentLat = _currentLat; - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { currentLat = newLocation; if (newLocation.horizontalAccuracy <= 100.0f) { [lm stopUpdatingLocation]; } [self.tableView reloadData]; } - (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error { NSString *msg = [[NSString alloc]initWithString:@"Error obtaining location"]; UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Error" message:msg delegate:nil cancelButtonTitle:@"Done" otherButtonTitles:nil]; [alert show]; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [self.barArray count]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier]; } //Get the object from the array. Bars *barObj = [self.barInfo objectAtIndex:indexPath.row]; //Set the name. cell.textLabel.text = barObj.barName; if (currentLat == nil) { cell.detailTextLabel.text = [NSString stringWithFormat:@"?"]; }else { cell.detailTextLabel.text = [NSString stringWithFormat:@"%.02f", cachedDist]; } // Set up the cell return cell; } - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { if ([[segue identifier] isEqualToString:@"ShowDetails"]) { TulsaDetailViewController *detailViewController = [segue destinationViewController]; detailViewController.detailItem = [self.barArray objectAtIndex:[self.tableView indexPathForSelectedRow].row]; } } - (void)viewDidLoad { [super viewDidLoad]; self.barArray = [BarDatabase database].barInfo; lm = [[CLLocationManager alloc] init]; lm.delegate = self; [lm startUpdatingLocation]; } - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; for (Bars *barObj in barArray) { NSString *strLat = barObj.Lat; NSString *strLong = barObj.Long; CLLocation *barLocation = [[CLLocation alloc] initWithLatitude:[strLat doubleValue] longitude:[strLong doubleValue]]; CLLocationDistance distance = [currentLat distanceFromLocation:barLocation]/1000; [barArray addObject:[NSNumber numberWithDouble:distance]]; NSSortDescriptor *sort=[NSSortDescriptor sortDescriptorWithKey:@"cachedDist" ascending:YES]; [barArray sortUsingDescriptors:[NSArray arrayWithObject:sort]]; } </code></pre> <p>For reference the rest of my code</p> <p>Bars.h</p> <pre><code>#import <Foundation/Foundation.h> @interface Bars : NSObject { NSString *barName; NSString *barAddress; NSString *Lat; NSString *Long; NSString *cachedDist; } @property (nonatomic, copy) NSString *barName; @property (nonatomic, copy) NSString *barAddress; @property (nonatomic, copy) NSString *Lat; @property (nonatomic, copy) NSString *Long; @property (nonatomic, copy) NSString *cachedDist; - (id)initWithName:(NSString *)name address:(NSString *)address latitude:(NSString *)latitude longitude:(NSString *)longitude distance:(NSString *)distance; @end </code></pre> <p>Bars.m</p> <pre><code>#import "Bars.h" @implementation Bars @synthesize barName = _barName; @synthesize barAddress = _barAddress; @synthesize Lat = _Lat; @synthesize Long = _Long; @synthesize cachedDist = _cachedDist; - (id)initWithName:(NSString *)name address:(NSString *)address latitude:(NSString *)latitude longitude:(NSString *)longitude distance:(NSString *)distance; { if ((self = [super init])) { self.barName = name; self.barAddress = address; self.Lat = latitude; self.Long = longitude; self.cachedDist = distance; } return self; } @end </code></pre> <p>BarDatabase.h</p> <pre><code>#import <Foundation/Foundation.h> #import <sqlite3.h> @interface BarDatabase : NSObject { sqlite3 *_database; } + (BarDatabase *)database; - (NSMutableArray *)barInfo; @end </code></pre> <p>BarDatabase.m</p> <pre><code>#import "BarDatabase.h" #import "Bars.h" @implementation BarDatabase static BarDatabase *_database; + (BarDatabase *)database { if (_database == nil) { _database = [[BarDatabase alloc] init]; } return _database; } - (id)init { if ((self = [super init])) { NSString *sqLiteDb = [[NSBundle mainBundle] pathForResource:@"TulsaBars" ofType:@"sqlite"]; if (sqlite3_open([sqLiteDb UTF8String], &_database) != SQLITE_OK) { NSLog(@"Failed to open database!"); } } return self; } - (void)dealloc { sqlite3_close(_database); } - (NSMutableArray *)barInfo { NSMutableArray *retval = [[NSMutableArray alloc] init]; NSString *query = @"SELECT * FROM TulsaBars"; sqlite3_stmt *statement; if (sqlite3_prepare_v2(_database, [query UTF8String], -1, &statement, nil) == SQLITE_OK) { while (sqlite3_step(statement) == SQLITE_ROW) { char *nameChars = (char *) sqlite3_column_text(statement, 1); char *addressChars = (char *) sqlite3_column_text(statement, 2); char *latChars = (char *) sqlite3_column_text(statement, 8); char *longChars = (char *) sqlite3_column_text(statement, 9); NSString *name = [[NSString alloc] initWithUTF8String:nameChars]; NSString *address = [[NSString alloc] initWithUTF8String:addressChars]; NSString *latitude = [[NSString alloc] initWithUTF8String:latChars]; NSString *longitude = [[NSString alloc] initWithUTF8String:longChars]; Bars *info = [[Bars alloc] initWithName:name address:address latitude:latitude longitude:longitude]; [retval addObject:info]; } sqlite3_finalize(statement); } return retval; } @end </code></pre>

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