UITableView没有显示我的数据？

Question

在此先感谢您阅读本文并尝试为我解决问题。

我已经使用sqlite 3构成了数据库，并且希望创建一个应用程序，在其中可以输入产品信息（应发送到数据库），然后可以在UIViewTable中查看该信息。

但是，创建完所有类和方法后-我的UIViewTable不显示数据库中的相关信息-它完全为空吗？

我收到一些反馈，说问题可能出在数据库未正确连接的事实上？

由于我的声誉很低，我只能附加2个链接，所以我试图显示最有用的屏幕截图，我相信它将提供信息。 他们在这个问题的底部。

以下是我所有的相关文件；

sqlite3数据库称为“ StockControl.db”

//Data.h

#import <Foundation/Foundation.h>

@interface Data : NSObject
{
NSString *name;
NSNumber *price;
NSNumber *quantity;
}

@property (strong, nonatomic) NSString *name;
@property (nonatomic, strong) NSNumber *price;
@property (nonatomic, strong) NSNumber *quantity;

-(id)initWithData:(NSString*)n thePrice:(NSNumber*)p theQuantity:(NSNumber*)q;

@end

//Data.m

#import "Data.h"

 @implementation Data
 @synthesize name, price, quantity;

 -(id)initWithData:(NSString*)n thePrice:(NSNumber*)p theQuantity:(NSNumber*)q{
if(self = [super init])
{
    [self setName:n];
    [self setPrice:p];
    [self setQuantity:q];
}
return self;
}

@end

//SiteCell.h

#import <UIKit/UIKit.h>

@interface SiteCell : UITableViewCell
{
UILabel *primaryLabel;
UILabel *secondaryLabel;
UIImageView *myImageView;
}

@property (strong, nonatomic) UILabel *primaryLabel;
@property (strong, nonatomic) UILabel* secondaryLabel;
@property (strong, nonatomic) UIImageView *myImageView;


@end

//SiteCell.m

#import "SiteCell.h"

@implementation SiteCell
@synthesize primaryLabel, secondaryLabel, myImageView;

-(id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier{
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if(self){
    primaryLabel = [[UILabel alloc] init];
    primaryLabel.textAlignment = NSTextAlignmentLeft;
    primaryLabel.font = [UIFont systemFontOfSize:18];
    primaryLabel.backgroundColor = [UIColor clearColor];
    primaryLabel.textColor = [UIColor whiteColor];

    secondaryLabel = [[UILabel alloc] init];
    secondaryLabel.textAlignment = NSTextAlignmentLeft;
    secondaryLabel.font = [UIFont systemFontOfSize:12];
    secondaryLabel.backgroundColor = [UIColor clearColor];
    secondaryLabel.textColor = [UIColor whiteColor];

    myImageView = [[UIImageView alloc]init];

    [self.contentView addSubview:myImageView];
    [self.contentView addSubview:primaryLabel];
    [self.contentView addSubview:secondaryLabel];
}
return self;
}

-(void)layoutSubviews{
[super layoutSubviews];

CGRect frame;

frame = CGRectMake(5, 5, 40, 40);
myImageView.frame = frame;

frame = CGRectMake(110, 5, 260, 20);
primaryLabel.frame = frame;

frame = CGRectMake(110, 30, 260, 20);
secondaryLabel.frame = frame;
}

- (void)awakeFromNib {
[super awakeFromNib];
// Initialization code
}

- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
[super setSelected:selected animated:animated];

// Configure the view for the selected state
}

@end

//StockPizza.h-包含UITableView的ViewController

#import <UIKit/UIKit.h>
#import "AppDelegate.h"
#import "SiteCell.h"

@interface StockPizza : UIViewController
<UITableViewDataSource, UITableViewDelegate>
{
AppDelegate *mainDelegate;
}

@property (strong, nonatomic) AppDelegate *mainDelegate;
@property (strong, nonatomic) IBOutlet UITableView *tableView;

@end

//StockPizza.m-存放UIViewTable的ViewController

#import "StockPizza.h"
#import <UIKit/UIKit.h>
#import "Data.h"
#import "SiteCell.h"

@interface StockPizza ()

@end

@implementation StockPizza
@synthesize mainDelegate;

#pragma mark Table Methods
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return [mainDelegate.stock count];
}

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
return 60;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
NSString *cellIdentifier = @"Cell";

SiteCell *cell = (SiteCell*)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];

if(cell == nil){
    cell = [[SiteCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}

NSInteger row = indexPath.row;
Data *d = [mainDelegate.stock objectAtIndex:row];
cell.primaryLabel.text = d.name;
cell.secondaryLabel.text = [d.price stringValue];

cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

return cell;
}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
NSInteger row = indexPath.row;

Data *person = [mainDelegate.stock objectAtIndex:row];

NSString *title = person.name;
NSString *msg = [person.quantity stringValue];

UIAlertController *alert = [UIAlertController alertControllerWithTitle:title message:msg preferredStyle:(UIAlertControllerStyleAlert)];

UIAlertAction *ok = [UIAlertAction actionWithTitle:@"Ok" style:(UIAlertActionStyleDefault) handler:nil];

[alert addAction:ok];
[self presentViewController:alert animated:YES completion:nil];
}

#pragma mark View Methods
- (void)viewDidLoad {
[super viewDidLoad];

self.mainDelegate = (AppDelegate*)[[UIApplication sharedApplication]delegate];

UITabBar *tabBar = self.tabBarController.tabBar;

[tabBar setBarTintColor: [UIColor blackColor]];
[tabBar setTintColor: [UIColor whiteColor]];
// Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/

@end

//AppDelegate.h

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>
{
NSString *databaseName;
NSString *databasePath;
NSMutableArray *stock;
}

@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) NSString *databaseName;
@property (strong, nonatomic) NSString *databasePath;
@property (strong, nonatomic) NSMutableArray *stock;

-(void)checkAndCreateDatabase;
-(void)readDataFromDatabase;

@end

//AppDelegate.m

#import "AppDelegate.h"
#import <sqlite3.h>
#import "Data.h"

@interface AppDelegate ()

@end

@implementation AppDelegate
@synthesize databaseName, databasePath, stock;

#pragma mark Database Methods
-(void)checkAndCreateDatabase{
BOOL success;

NSFileManager *fileManager = [NSFileManager defaultManager];

success = [fileManager fileExistsAtPath:self.databasePath];

if (success)
     return;

NSString *dataBasePathFromApp = [[[NSBundle mainBundle]resourcePath]stringByAppendingPathComponent:self.databaseName];

[fileManager copyItemAtPath:dataBasePathFromApp toPath:self.databasePath error:nil];
}

-(void)readDataFromDatabase{
[self.stock removeAllObjects];

sqlite3 *database;

if (sqlite3_open([self.databasePath UTF8String], &database) == SQLITE_OK) {
    char *sqlStatement = "select * from entries";
    sqlite3_stmt *compiledStatement;

    if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK){
        while(sqlite3_step(compiledStatement) == SQLITE_ROW){
            char *n = (char*)sqlite3_column_text(compiledStatement, 1);
            float p = sqlite3_column_int(compiledStatement, 2);
            int q = sqlite3_column_int(compiledStatement, 3);

            NSString *name = [NSString stringWithUTF8String:n];
            NSNumber *price = [NSNumber numberWithFloat:p];
            NSNumber *quantity = [NSNumber numberWithInt:q];

            Data *data = [[Data alloc] initWithData:name thePrice:price theQuantity:quantity];
            [self.stock addObject:data];
        }
    }
    sqlite3_finalize(compiledStatement);
}
sqlite3_close(database);
}


#pragma mark App Methods
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
self.stock = [[NSMutableArray alloc]init];
self.databaseName = @"StockControl.db";

NSArray * documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * documentsDir = [documentPaths objectAtIndex:0];

self.databasePath = [documentsDir stringByAppendingPathComponent: self.databaseName];

[self checkAndCreateDatabase];
[self readDataFromDatabase];


return YES;
}


- (void)applicationWillResignActive:(UIApplication *)application {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
}


- (void)applicationDidEnterBackground:(UIApplication *)application {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}


- (void)applicationWillEnterForeground:(UIApplication *)application {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}


- (void)applicationDidBecomeActive:(UIApplication *)application {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}


- (void)applicationWillTerminate:(UIApplication *)application {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}


@end

截图

带插座的UIViewTable || 故事板概述

Answer 1

我认为Mridul是正确的，并且您只是缺少一个出口，但是您可以做一些事情来帮助您进行调试。

也许您已经确认您实际上正在获取期望的数据-但您没有说已经检查过了。 我认为总是值得进行一些调试检查或打印语句，以确保您确实获得了期望的数据。

另一件事是，您似乎将为每个表视图都具有单独的类-您可以通过拥有一个演示文稿类来处理所有表视图开销来简化很多事情，并且只需从5个表中加载所需的数据不同的来源。

Answer 2

在readDataFromDatabase（）中，您需要执行以下操作：

浮点p = sqlite3_column_int（compiledStatement，2）;

它应显示为float p = sqlite3_column_float（compiledStatement，2）;

Answer 3

谢谢你们的努力！

事实证明这是我自己的错，因为数据库中的表被命名为“ stock”，而我的sqlStatement试图调用名为entry的表。 更改此错误后，将其显示为我想要的！

对此我深表歉意，但是感谢您的见解。