Question

我有一个NSMutableArray，我想用sqlite数据库填充并在表视图中显示数据。该应用程序构建并显示＆＃34;数据库已打开＆＃34;在控制台，但只是显示一个空的tableview，我有它完美的工作但突然似乎已停止工作。这是将数据添加到数组的代码：

    #import "ViewController.h"

    @interface ViewController ()

    @end

    @implementation ViewController
    @synthesize entries;

    - (void)viewDidLoad
    {
        [super viewDidLoad];
        //[entries addObject:@"object1"];
        //[entries addObject:@"object2"];
        //[entries addObject:@"object3"];
        //[entries addObject:@"object4"];
        [self openDB];
        entries = [[NSMutableArray alloc] init];
        NSString *sql = [NSString stringWithFormat:@"SELECT * FROM speakers ORDER BY name"];
        sqlite3_stmt *statement;

        if(sqlite3_prepare_v2(db, [sql UTF8String], -1, &statement, nil)==SQLITE_OK)
        {
            while (sqlite3_step(statement)==SQLITE_ROW) {

                char *field2 = (char *) sqlite3_column_text(statement,1);
                NSString *field2Str = [[NSString alloc]initWithUTF8String:field2];

                NSString *str = [[NSString alloc]initWithFormat:@"%@", field2Str];
                [entries addObject:str ];


            }
        }
    }
//file path to db
-(NSString *) filePath {
    NSArray *paths = NSSearchPathForDirectoriesInDomains
    (NSDocumentDirectory, NSUserDomainMask, YES);
    return [[paths objectAtIndex:0] stringByAppendingPathComponent:@"speakerdb.sqlite"];
}

//open the db
-(void)openDB {
    if (sqlite3_open([[self filePath] UTF8String], &db) != SQLITE_OK){
        sqlite3_close(db);
        NSAssert(0,@"error preparing statement: %s", sqlite3_errmsg(db));
    }else{
        NSLog(@"database opened");
    }
}

NSMutableArray在头文件中定义如下：

#import <UIKit/UIKit.h>
#import "sqlite3.h"
#import "speakerViewController.h"

@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>{
    IBOutlet UITableView *theTable;
    sqlite3 *db;
}
@property (nonatomic,retain) NSMutableArray *entries;
@end

以下是将数据添加到表视图的代码：

-(NSInteger) numberOfSectionsInTableView:(UITableView *)tableView
{
    //return the number of sections.
    return 1;
}

-(NSInteger)tableView:(UITableView *) tableView numberOfRowsInSection:(NSInteger)section
{
    //Return the number of rows in the section
    return [entries count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

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

    //Congigure the cell...
    cell.textLabel.text = [entries objectAtIndex:indexPath.row];
    return cell;
}

数据显示在表视图中是否手动将对象添加到数组中（注释掉了viewDidLoad方法中显示的行）但似乎无法使用sqlite数据库。

非常感谢任何帮助。

编辑：我正在使用xcode 5.1.1

Answer 1

尝试调试代码...在NSString *field2Str = [[NSString alloc]initWithUTF8String:field2];行放置一个断点，并检查field2是否为空......

尝试像这样打开db：

 NSString *sqLiteDb = [[NSBundle mainBundle] pathForResource:@"speakerdb"
                                                             ofType:@"sqlite"];

        if (sqlite3_open([sqLiteDb UTF8String], &_database) != SQLITE_OK) {
            NSLog(@"Failed to open database!");
        }

您的代码中缺少一件事：

    sqlite3_finalize(statement);

像这样使用它：

if(sqlite3_prepare_v2(db, [sql UTF8String], -1, &statement, nil)==SQLITE_OK)
        {
            while (sqlite3_step(statement)==SQLITE_ROW) {

                char *field2 = (char *) sqlite3_column_text(statement,1);
                NSString *field2Str = [[NSString alloc]initWithUTF8String:field2];

                NSString *str = [[NSString alloc]initWithFormat:@"%@", field2Str];
                [entries addObject:str ];


            }
        sqlite3_finalize(statement);

        }

来自sqlite数据库的NSMutableArray addObject无法正常工作

1 个答案: