问题
I'm working on an iPhone project in Xcode 4.3 with SQlite3, the connection between the SQlite and Xcode is done, now I want to display my data into a table views (three views) and its read only! so I have the main table view, select raw --> take to 2nd view and load other data from the DB select raw --> take to the details view to display long text and image!
Any help appreciated.
AppDelegate.h
#import "AppDelegate.h"
#import "MasterViewController.h"
@implementation AppDelegate
@synthesize window = _window;
@synthesize navigationController = _navigationController;
- (void)dealloc
{
[_window release];
[_navigationController release];
[super dealloc];
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
NSString *dbPath = [documentsDir stringByAppendingPathComponent:@"cities.sqlite"];
NSFileManager *fileManager = [NSFileManager defaultManager];
BOOL success = [fileManager fileExistsAtPath:dbPath];
if (success) {
NSLog(@"we have the database");
} else {
NSLog(@"we have no database");
NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"cities.sqlite"];
BOOL moved = [fileManager copyItemAtPath:defaultDBPath toPath:dbPath error:nil];
if (moved) {
NSLog(@"database copied");
}
}
MasterViewController *masterViewController = [[[MasterViewController alloc] initWithNibName:@"MasterViewController" bundle:nil] autorelease];
self.navigationController = [[[UINavigationController alloc] initWithRootViewController:masterViewController] autorelease];
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];
return YES;
}
MasterViewController.h
#import <UIKit/UIKit.h>
#import <sqlite3.h>
@class DetailViewController;
@interface MasterViewController : UITableViewController {
NSMutableArray *cities;
}
@property (strong, nonatomic) DetailViewController *detailViewController;
@end
MasterViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
students = [[NSMutableArray alloc] init];
countries = [[NSMutableArray alloc] init];
// Do any additional setup after loading the view, typically from a nib.
self.navigationItem.leftBarButtonItem = self.editButtonItem;
UIBarButtonItem *addButton = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)] autorelease];
self.navigationItem.rightBarButtonItem = addButton;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
NSString *dbPath = [documentsDir stringByAppendingPathComponent:@"cities.sqlite"];
sqlite3 *database;
if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK) {
const char *sqlStatement = "select * from cities_info";
sqlite3_stmt *compileStatement;
if (sqlite3_prepare_v2(database, sqlStatement, -1, &compileStatement, NULL) == SQLITE_OK) {
while (sqlite3_step(compileStatement) == SQLITE_ROW) {
NSLog(@"one record");
NSString *cityName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compileStatement, 1)];
[cities addObject:cityName];
}
NSLog(@"cities: %@",cities);
}
} else {
NSLog(@"error in database");
}
}
Blockquote
回答1:
I suggest a light wrapper over SQLite - see https://github.com/JohnGoodstadt/EasySQLite
This will allow:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return _personTable.rows.count;
}
AND
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
...
NSArray* row= _personTable.rows[indexPath.row];
cell.textLabel.text = row[[_personTable colIndex:@"lastname"]];
...
Set this up by using an iVar representing a SQL Table:
self.personTable = [_db ExecuteQuery:@"SELECT firstname , lastname , age , salary FROM person"];
And a DB Connection iVar passing in your SQL file name:
self.db = [DBController sharedDatabaseController:@"DataTable.sqlite"];
回答2:
First of all, I suggest using FMDB, which is an Objective-C wrapper around sqlite3. Secondly, I'd create a custom Data Access Object with a shared instance, like so:
@interface MyDatabaseDAO : NSObject
@property (nonatomic, strong) FMDatabase *database;
@end
@implementation MyDatabaseDAO
@synthesize database = _database;
+ (MyDatabaseDAO *)instance {
static MyDatabaseDAO *_instance = nil;
@synchronized (self) {
if (_instance == nil) {
_instance = [[self alloc] init];
}
}
return _instance;
}
- (id)init {
self.database = [FMDatabase databaseWithPath:myDatabasePath];
[self.database open];
}
- (void)dealloc {
[self.database close];
}
@end
This DAO must have 3 access methods: one for each data object in the database. Because you weren't specific, I made these objects without any specific properties.
- (NSArray *)retrieveAllFirstViewItems {
NSMutableArray *items = [NSMutableArray array];
FMResultSet *resultSet = [FMDBDatabase.database executeQuery:@"SELECT * FROM myFirstViewItemTable"];
while ([resultSet next]) {
// extract whatever data you want from the resultset
NSString *name = [resultSet stringForColumn:@"name"]
[items addObject:name];
}
[resultSet close];
return items;
}
- (MySecondViewItem *)retrieveSecondViewItemFromIndexPath:(NSIndexPath *)indexPath {
FMResultSet *resultSet = [FMDBDatabase.database executeQuery:@"SELECT * FROM mySecondViewItemTable WHERE pid = ?", [indexPath indexAtPosition:0]];
if ([resultSet next]) {
// extract whatever data you want from the resultset
NSString *name = [resultSet stringForColumn:@"name"]
MySecondViewItem *mySecondViewItem = [[MySecondViewItem alloc]
initWithName:name withPID:[indexPath indexAtPosition:0]];
[resultSet close];
return mySecondViewItem;
} else {
return nil;
}
}
- (MyThirdViewItem *)retrieveThirdViewItemFromIndexPath:(NSIndexPath *)indexPath {
FMResultSet *resultSet = [FMDBDatabase.database executeQuery:@"SELECT * FROM mySecondViewItemTable WHERE pid = ?", [indexPath indexAtPosition:1]];
if ([resultSet next]) {
// extract whatever data you want from the resultset
NSString *name = [resultSet stringForColumn:@"name"]
MyThirdViewItem *myThirdViewItem = [[MyThirdViewItem alloc]
initWithName:name withPID:[indexPath indexAtPosition:1]];
[resultSet close];
return myThirdViewItem;
} else {
return nil;
}
}
Since it's read-only, these are all the required methods. In your first UITableView, just implement method:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
MySecondViewItem *mySecondViewItem = [[MyDatabaseDAO instance] retrieveSecondViewItemFromIndexPath:indexPath];
//instantiate a view from this item and use [UINavigationController pushViewController:animated:] to navigate to it
}
All that's left is just to show your data objects in views somehow. I sugget doing as much of the data retrieval as possible in the Data Access Object so that the view controllers can read the properties of the data objects without having to worry about the backend.
That's all there is to it! I hope this helped
来源：https://stackoverflow.com/questions/10149368/how-to-display-data-from-sqlite-into-table-views-to-iphone-app