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中，所以我有一個條形碼掃描應用程序應該讀取條形碼，將其與數據庫中的條目進行匹配，並顯示有關條目的所有其他信息。無法從SQLite數據庫獲取數據以顯示在iOS應用程序
我使用的單個文件數據庫名爲trackeddb.sqlite，它是使用終端和sqlite3命令創建的。它包含兩個表格，一個用於填寫「第一次掃描」條目的關於產品的靜態信息（每個零件號碼都是唯一的，並有自己的條目），另一個表格包含相同的產品信息以及條形碼。第二個表格允許用戶存儲具有相同部件號和規格的多個產品，但使用條形碼創建唯一條目。
我的問題是，當條形碼掃描時，應該顯示存儲在第二個表中的信息（如果條形碼匹配）。代碼是健全的，但是當我運行條形碼時（在第二個表中輸入條目後），它不會顯示預設文本以外的任何數據。我已經絞盡腦汁想到了這一點，但我想不出來，但我認爲這可能與我如何引用我的數據庫有關。
謝謝你的時間！
What I am greeted with when I scan the barcodes
這是sqlite的DB
PasteBin link to sqlite db and schema
數據庫從這種方法稱爲
- (id)init {
if ((self = [super init])) {
NSString* sqLiteDb = [[NSBundle mainBundle] pathForResource:@"trackeddb" ofType:@"sqlite"];
if (sqlite3_open([sqLiteDb UTF8String], &_database) != SQLITE_OK) {
NSLog(@"Failed to open database");
}
}
return self;
}
這裏是我的代碼的主要部分，條形碼掃描器作品完美無缺，所以我不會在那裏發帖。這僅用於數據庫。
TrackerDatabase.m
//TrackerDatabase.m
#import "TrackerDatabase.h"
#import "TrackedItems.h"
#import "Barcode.h"
@interface TrackerDatabase()
@end
@implementation TrackerDatabase
static TrackerDatabase *_database;
+ (TrackerDatabase*)database {
if (_database == nil) {
_database = [[TrackerDatabase alloc] init];
}
return _database;
}
- (id)init {
if ((self = [super init])) {
NSString* sqLiteDb = [[NSBundle mainBundle] pathForResource:@"trackeddb" ofType:@"sqlite"];
if (sqlite3_open([sqLiteDb UTF8String], &_database) != SQLITE_OK) {
NSLog(@"Failed to open database");
}
}
return self;
}
- (void)dealloc {
sqlite3_close(_database);
}
- (NSArray *)trackedItems:(NSString *)barcode {
NSMutableArray *retval = [[NSMutableArray alloc] init];
NSString *query = @"SELECT * from Tracked WHERE barcode=";
query = [query stringByAppendingString:barcode];
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(_database, [query UTF8String], -1, &statement, nil) == SQLITE_OK) {
while (sqlite3_step(statement) == SQLITE_ROW) {
char *barcodeChars = (char *) sqlite3_column_text(statement, 0);
char *partNumChars = (char *) sqlite3_column_text(statement, 1);
char *descChars = (char *) sqlite3_column_text(statement, 2);
char *colorChars = (char *) sqlite3_column_text(statement, 3);
char *sizeChars = (char *) sqlite3_column_text(statement, 4);
char *leadChars = (char *) sqlite3_column_text(statement, 5);
char *manufacturerChars = (char *) sqlite3_column_text(statement, 6);
NSString *barcode = [[NSString alloc] initWithUTF8String:barcodeChars];
NSString *partNum = [[NSString alloc] initWithUTF8String:partNumChars];
NSString *desc = [[NSString alloc] initWithUTF8String:descChars];
NSString *color = [[NSString alloc] initWithUTF8String:colorChars];
NSString *size = [[NSString alloc] initWithUTF8String:sizeChars];
NSString *lead = [[NSString alloc] initWithUTF8String:leadChars];
NSString *manufacturer = [[NSString alloc] initWithUTF8String:manufacturerChars];
TrackedItems *items = [[TrackedItems alloc] initWithBarcode:barcode partNum:partNum desc:desc
color:color size:size lead:lead manufacturer:manufacturer];
[retval addObject:items];
}
sqlite3_finalize(statement);
}
return retval;
}
@end
TrackerDatabase.h
//TrackerDatabase.h
#import <Foundation/Foundation.h>
#import <sqlite3.h>
@interface TrackerDatabase : NSObject {
sqlite3 *_database;
}
+ (TrackerDatabase*)database;
- (NSArray *)trackedItems:(NSString*)barcode;
@end
TrackedItems.m
#import "TrackedItems.h"
@implementation TrackedItems
@synthesize barcode = _barcode;
@synthesize partNum = _partNum;
@synthesize desc = _desc;
@synthesize color = _color;
@synthesize size = _size;
@synthesize lead = _lead;
@synthesize manufacturer = _manufacturer;
- (id)initWithBarcode:(NSString *)barcode partNum:(NSString *)partNum desc:(NSString *)desc
color:(NSString *)color size:(NSString *)size lead:(NSString *)lead
manufacturer:(NSString *)manufacturer {
if ((self = [super init])) {
self.barcode = barcode;
self.partNum = partNum;
self.desc = desc;
self.color = color;
self.size = size;
self.lead = lead;
self.manufacturer = manufacturer;
}
return self;
}
- (void) dealloc {
self.barcode = nil;
self.partNum = nil;
self.desc = nil;
self.color = nil;
self.size = nil;
self.lead = nil;
self.manufacturer = nil;
}
@end
TrackedItems.h
#import <Foundation/Foundation.h>
@interface TrackedItems : NSObject {
NSString *_barcode;
NSString *_partNum;
NSString *_desc;
NSString *_color;
NSString *_size;
NSString *_lead;
NSString *_manufacturer;
}
@property (nonatomic, copy) NSString *barcode;
@property (nonatomic, copy) NSString *partNum;
@property (nonatomic, copy) NSString *desc;
@property (nonatomic, copy) NSString *color;
@property (nonatomic, copy) NSString *size;
@property (nonatomic, copy) NSString *lead;
@property (nonatomic, copy) NSString *manufacturer;
- (id)initWithBarcode:(NSString *)barcode partNum:(NSString *)partNum desc:(NSString *)desc
color:(NSString *)color size:(NSString *)size lead:(NSString *)lead
manufacturer:(NSString *)manufacturer;
@end
從以往的經驗，我建議先從只是一個數據庫字段，並確保進來正確。 – GuybrushThreepwood