Question

所以我正在做的是用户从相机胶卷中拾取图像，并且我正在使用该图像设置imageView。到现在为止还挺好。现在我需要将此图像保存到我的数据库中。所以当下次加载视图时我再次选择了该图像。问题是我的图像视图没有与图像一起设置。可能是因为它未正确保存到我的数据库中。从我所阅读的NSData最好使用它和我正在使用但没有成功。有人可以帮我解决问题吗？

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    [self dismissViewControllerAnimated:YES completion:nil];
    fsImageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];
    fsUIImage = [info objectForKey:UIImagePickerControllerOriginalImage];
    imgData = UIImagePNGRepresentation(fsUIImage);
    [self saveImageToDatabase];

}

------在这里，我将图像保存到DB -------

-(void)saveImageToDatabase{

    [self openDB];

    sqlite3_stmt *newstatement;

    int originalTotalCount = sqlite3_total_changes(db);

    NSString *sql = [NSString stringWithFormat:@"UPDATE Annotation SET image = '%@' WHERE title ='%@'", imgData, fsTitleName];
    if (sqlite3_prepare_v2(db, [sql UTF8String], -1, &newstatement, nil) != SQLITE_OK) {
        NSLog(@"%s: prepare failed: %s", __FUNCTION__, sqlite3_errmsg(db));
    } else {
        if (sqlite3_step(newstatement) != SQLITE_DONE) {
            NSLog(@"%s: step failed: %s", __FUNCTION__, sqlite3_errmsg(db));
        } else {
            int rowsUpdated = sqlite3_total_changes(db) - originalTotalCount;

            NSString *message;

            if (rowsUpdated == 1)
                message = @"Updated one row";
            else if (rowsUpdated == 0)
                message = @"No rows updated";
            else
                message = [NSString stringWithFormat:@"Updated %d rows", rowsUpdated]; 

            NSLog(@"%@", message);

            sqlite3_step(newstatement);
        }

        sqlite3_finalize(newstatement);
    }
    sqlite3_close(db);

}

------这里我从DB中提取我的图像-------在viewLoads ..

时调用

-(void)setImage{

    [self openDB];

    NSString *sql = [NSString stringWithFormat:@"SELECT image FROM Annotation WHERE title = '%@'",fsTitleName];

    sqlite3_stmt *statement;

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

        int rc;
        if ((rc = sqlite3_step(statement)) == SQLITE_ROW) {
            char *field1 = (char *) sqlite3_column_text(statement, 0);
            NSString *field1Str = [[NSString alloc]initWithUTF8String:field1];
            imgData = [field1Str dataUsingEncoding:NSUTF8StringEncoding];
            [fsImageView setImage:[UIImage imageWithData: imgData]];

        } else if (rc != SQLITE_DONE) {
            NSLog(@"%s: sqlite3_step failed: %s", __FUNCTION__, sqlite3_errmsg(db));
        }
    } else {
        NSLog(@"%s: sqlite3_prepare_v2 failed: %s", __FUNCTION__, sqlite3_errmsg(db));
    }

    sqlite3_finalize(statement);
    sqlite3_close(db);


}

Answer 1

在您的情况下，您成功从UIImagePicker获取图像并将其转换为NSData以存储在sqlite中，您面临的唯一问题是将NSData存储到sqlite中。

将NSData保存到sqlite数据库需要将其保存为sqlite中的字节，因此要么以字节存储NSData，要么将其转换为Base64字符串，然后在sqlite中使用Base64字符串。

要将sqlite中的NSData存储为字节，可以参考下面的链接：

1）How to retrieve string from NSData stored in sqlite?

2）Retrieve nsdata from sqlite stored in Blob data type for iPhone App

要将NSData作为Base64存储在sqlite中，您可以使用以下易于使用的Base64库。

https://github.com/nicklockwood/Base64

现在将NSData转换为Base64只需使用以下代码：

NSString *aStrData = [theNSDataObject base64EncodedString];

然后从数据库中获取后，将Base64字符串转换回NSData，如下所示：

NSData *theNSDataObject = [aStrData base64DecodedData];

我更喜欢使用Base64字符串是一种好方法，所以如果你以后想要将图像发送到任何网络服务，你也可以用base64格式发送它。

Answer 2

//使用此代码进行插入

  NSString *insertSQL = [NSString stringWithFormat:@"INSERT INTO <Table Name> (Image) VALUES (?)"];

        const char *insert_stmt = [insertSQL UTF8String];

        if(sqlite3_prepare_v2(contactDB, insert_stmt, -1, &statement, NULL)== SQLITE_OK)
        {

            sqlite3_bind_blob( statement, 1, [imageData bytes],(unsigned int) [imageData length], SQLITE_TRANSIENT);
        }

//使用此代码进行检索

if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
    {

        NSString *querySQL = [NSString stringWithFormat:
                              @"SELECT * FROM <Table Name>" ];
        const char *query_stmt = [querySQL UTF8String];

        if (sqlite3_prepare_v2(contactDB,
                               query_stmt, -1, &statement, NULL) == SQLITE_OK)
        {
            while (sqlite3_step(statement) == SQLITE_ROW)
            {


                int blobBytesLength = sqlite3_column_bytes(statement, 1);
                NSData *blobData = [[NSData alloc]initWithBytes:sqlite3_column_blob(statement, 1)length:blobBytesLength];

                UIImage *imagetest = [[UIImage alloc] initWithData:blobData];//this is your Image
          }
       }

将图像从UIImagePicker保存到Sqlite DB

2 个答案: