iphone从数据库读取图像的问题

Question

嗨，我可以使用以下代码将图像存储到数据库中......

-(void)insertimages: (NSData *)image
{
    if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK)
    {
        NSUInteger len = [image length];
        NSLog(@"data size is %d", len);

        sqlStatement="insert into messages values(10,?)";
        if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK)
        {
            //sqlite3_bind_int(compiledStatement, 1, -1);
            //sqlite3_bind_blob(updateStmt, 3, [imgData bytes], [imgData length], NULL);
            sqlite3_bind_blob(compiledStatement, 1, [image bytes], [image length], SQLITE_TRANSIENT);
            //sqlite3_bind_text(compiledStatement, 1, [SMSBody UTF8String],-1,SQLITE_STATIC);
            if(sqlite3_step(compiledStatement) == SQLITE_DONE) 
            {
                sqlite3_finalize(compiledStatement);                
            }

        }       
        sqlite3_close(database);    
    }   
}

但现在我的问题是我无法从数据库中检索图像并将其显示在 uiimageview 中......

任何人都可以请帮助我该怎么做。

Answer 1

使用以下方法从数据库读取图像数据并将图像存储在数组或字典中

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

    // Init the img Array
    imageArray = [[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 messages";
        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
                NSURL *url = [NSURL URLWithString:[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)]];
];
                NSData *imgData = [NSData dataWithContentsOfURL: url];

                // Create a new image object with the data from the database
                iconImage.image=[UIImage imageWithData:imgData];

                // Add the img object to the img Array
                [imageArray addObject:iconImage];
            }
        }
        // Release the compiled statement from memory
        sqlite3_finalize(compiledStatement);

    }
    sqlite3_close(database);

}

Answer 2

一年前我试图这样做，我编写了代码，使用 osx sdk 将图像保存到 sqlite3 数据库中（我能够写入和读取，我什至可以使用 ruby​​ 将图像存储在数据库中并读取它们）与 macosx sdk）。但当我将这段代码移至 iOS 应用程序时，它会提取出错误数据。如果你解决了这个问题，我想知道答案。