首先,我知道不应该使用SQLite数据库来存储图像,但我只是存储网站的favicon,它们非常小。
我的问题是,我尝试将这些favicon插入到数据库中(似乎可以工作),我使用NSImage
的-tiffRepresentation
方法将favicon转换为NSData
,然后将其插入到我的数据库中的blob列中:
NSImage *favico = [webview mainFrameIcon];
[appDelegate insertBookmark:[titleField stringValue] url:[urlfield stringValue] data:[favico TIFFRepresentation]]
SQLite的方法如下所示:
-(void)insertBookmark:(NSString *)title url:(NSString *)url data:(NSData *)data
{
NSData *imagedata = [[NSData alloc]initWithData:data];
sqlite3 *database;
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
NSString *query = [NSString stringWithFormat:@"INSERT INTO Bookmarks (title, url, image) VALUES ('%@', '%@', '%@')",title, url, data];
const char *querychar = [query UTF8String];
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(database, querychar, -1, &statement, NULL) == SQLITE_OK)
{
int row = 3;
sqlite3_bind_blob(statement, row, [imagedata bytes], [imagedata length], NULL);
sqlite3_step(statement);
sqlite3_finalize(statement);
}
else
{
NSLog(@"Error");
}
[databasePath retain];
[databaseName retain];
}
sqlite3_close(database);
[imagedata release];
}
当我查看数据库时,我发现在图像列中有
<data>
的值(正常吗?)。现在,当我从数据库中提取blob并尝试将其放入对象中时,我的NSImage为null。
-(void) readDatabase {
// Setup the database object
sqlite3 *database;
bookmarks = [[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 Bookmarks ORDER BY title ASC";
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 *aTitle = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
NSString *aUrl = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
NSData *data = [[NSData alloc] initWithBytes:sqlite3_column_blob(compiledStatement, 3) length:sqlite3_column_bytes(compiledStatement, 3)];
NSImage *image = [[NSImage alloc]initWithData:data];
bookmarkObject *bookmark = [[bookmarkObject alloc] initWithName:aTitle url:aUrl favico:image];
[bookmarks addObject:bookmark];
[bookmark release];
[data release];
[image release];
}
}
// Release the compiled statement from memory
sqlite3_finalize(compiledStatement);
sqlite3_close(database);
[databasePath retain];
[databaseName retain];
}
}
Thanks in advance