iPhone - SQLite-Datenbank Gelesen

Question

Ich versuche, eine grundlegende Anwendung zu tun.
Meine Dateien Liste:

DatabaseClass.h and .m, 
IDRGameAppDelegate.h and .m, 
scoredb.sqlite, 
ScoreViewController.h and .m, 
MainWindow.xib // Main Window 
ScoreWindow.xib //Show Score Window 

1.) meine Datenbank ist;

CREATE TABLE "game" ("id" INTEGER PRIMARY KEY ,"name" VARCHAR(32),"score" VARCHAR(20)); 
INSERT INTO "game" VALUES(1,'interclock','1.234'); 
INSERT INTO "game" VALUES(2,'dui','345'); 
INSERT INTO "game" VALUES(3,'reflex','987'); 

2-) erstellt und i DatabaseClass.h DatabaseClass.m

DatabaseClass.h ist:

#import <Foundation/Foundation.h> 
@interface DatabaseClass : NSObject { 

    NSString *name; 
    NSString *score; 
} 
@property (nonatomic, retain) NSString *name; 
@property (nonatomic, retain) NSString *score; 
-(id)initWithName:(NSString *)n score:(NSString *)s; 
@end 

DatabaseClass.m ist;

#import "DatabaseClass.h" 
@implementation DatabaseClass 
@synthesize name, score; 
-(id)initWithName:(NSString *)n score:(NSString *)s{ 
    self.name = n; 
    self.score = s; 
    return self; 
} 
@end 

meine IDRGameAppDelegate.h ist;

#import <UIKit/UIKit.h> 
#import <sqlite3.h> // Import the SQLite database framework 

@class IDRGameViewController , ScoreViewController ; 


@interface IDRGameAppDelegate : NSObject <UIApplicationDelegate> { 

    IBOutlet UIWindow *window; 
    IBOutlet IDRGameViewController *viewController; 
    IBOutlet ScoreViewController *scoreViewController; 


    // Database variables 
    NSString *databaseName; 
    NSString *databasePath; 

    // Array to store the animal objects 
    NSMutableArray *scores; 
} 

- (void)flipToScore; 
- (void)scoreToMainBack; 

-(void) checkAndCreateDatabase; 
-(void) readScoreFromDatabase; 

@property (nonatomic, retain) UIWindow *window; 
@property (nonatomic, retain) IDRGameViewController *viewController; 
@property (nonatomic, retain) ScoreViewController *scoreViewController; 
@property (nonatomic, retain) NSMutableArray *scores; 

@end 

IDRGameAppDelegate.m ist;

#import "IDRGameAppDelegate.h" 
#import "IDRGameViewController.h" 
#import "ScoreViewController.h" 
#import "DatabaseClass.h" 


@implementation IDRGameAppDelegate 

@synthesize window; 
@synthesize viewController; 
@synthesize scoreViewController; 

@synthesize scores; 



- (void)applicationDidFinishLaunching:(UIApplication *)application { 

    // Setup some globals 
    databaseName = @"scoredb.sqlite"; 

    // 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]; 

    // Query the database for all animal records and construct the "animals" array 
    [self readScoreFromDatabase]; 

    // Override point for customization after app launch  
    [window addSubview:viewController.view]; 
    [window makeKeyAndVisible]; 
} 

- (void)dealloc { 
    [scores release]; 
    [viewController release]; 
    [window release]; 
    [super dealloc]; 
} 


-(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) readScoreFromDatabase { 
    // Setup the database object 
    sqlite3 *database; 

    // Init the animals Array 
    scores = [[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 * from game"; 
     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 

       NSString *aName =[NSString stringWithCString:(char *)sqlite3_column_text(compiledStatement, 2)]; 
       NSString *aScore =[NSString stringWithCString:(char *)sqlite3_column_text(compiledStatement, 3)]; 

       //NSString *aName = [NSString stringWithString:(NSString *)sqlite3_column_text(compiledStatement, 2)]; 
       //NSString *aScore = [NSString stringWithString:(NSString *)sqlite3_column_text(compiledStatement, 3)]; 



       // Create a new animal object with the data from the database 
       DatabaseClass *dbOBJ = [[DatabaseClass alloc] initWithName:aName score:aScore]; 

       // Add the animal object to the animals Array 
       [scores addObject:dbOBJ]; 

       [dbOBJ release]; 
      } 
     } 
     // Release the compiled statement from memory 
     sqlite3_finalize(compiledStatement); 

    } 
    sqlite3_close(database); 

} 


- (void)flipToScore { 


    ScoreViewController *aSecondView = [[ScoreViewController alloc] initWithNibName:@"ScoreWindow" bundle:nil]; 
    [self setScoreViewController:aSecondView]; 
    [aSecondView release]; 

    [UIView beginAnimations:nil context:NULL]; 
    [UIView setAnimationDuration:2.0]; 
    [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:window cache:YES]; 
    [viewController.view removeFromSuperview]; 
    [self.window addSubview:[scoreViewController view]]; 
    [UIView commitAnimations]; 

} 

- (void)scoreToMainBack { 



    [UIView beginAnimations:nil context:NULL]; 
    [UIView setAnimationDuration:2.0]; 
    [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:window cache:NO]; 


    [scoreViewController.view removeFromSuperview]; 
    [self.window addSubview:[viewController view]]; 

    [UIView commitAnimations]; 


    [scoreViewController release]; 
    scoreViewController = nil; 

} 
@end 

ScoreViewController.h ist;

#import <UIKit/UIKit.h> 

@interface ScoreViewController : UIViewController { 

    IBOutlet UILabel *gameNameLabel; 
    IBOutlet UILabel *gameScoreLabel; 


} 
@property (nonatomic, retain) IBOutlet UILabel *gameNameLabel; 
@property (nonatomic, retain) IBOutlet UILabel *gameScoreLabel; 

-(IBAction)refreshClick:(id)sender; 

@end 

und schließlich ScoreViewController.m ist;

Problem ist: wenn ich auf refreshButton klicke, ist Programm sperren und brechen, aber ich kann keinen Fehler sehen.

Das Programm funktioniert nicht Ich habe keine Datenbankeinträge gelesen und angezeigt. Was ist das Problem?

Answer 1

Warum haben Sie sich entschieden, direkt mit SQLite auf dem iPhone zu bleiben? Nachdem iPhone OS 3.0 für alle iPhone-Benutzer verfügbar ist, würde ich empfehlen, diese Datenbankabstraktion zu verwenden. Es ist ziemlich einfach zu benutzen und es verhindert, dass Sie einen Haufen Datenbankzugriffscode programmieren.

Auf Mike Swans Blog ist eine nützliche Einführung in Kerndaten, die als Ausgangspunkt für Ihre Entwicklung dienen können.

Als Teil der iPhone-Referenzdokumentation veröffentlichte Apple eine Core Data Tutorial for the iPhone OS, die die spezifischen Funktionen des iPhone abdeckt.

Ich habe es in einer eigenen Anwendung verwendet und fand es wirklich zeitsparend verglichen mit dem SQLite-Datenbankcode, den ich vorher hatte.