图像由 UIImagePickerController SourceType Camera 拍摄，如何将其保存在 ios 的数据库中

Question

在 .m 中编码

-(IBAction) getPhoto:(id) sender {
    picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;

} else {
    if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        UIAlertView *noCameraAlert = [[UIAlertView alloc] initWithTitle:@"Error"
                                                                message:@"You don't have a camera for this device" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];

        //shows above alert if there's no camera
        [noCameraAlert show];
    }else{
        picker.sourceType    = UIImagePickerControllerSourceTypeCamera;
        picker.allowsEditing = YES;
        picker.delegate      = self;
    }
}
[self presentViewController:picker animated:YES completion:nil];
}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
     UIImage *img     = [info objectForKey:UIImagePickerControllerOriginalImage];
img              = [info valueForKey:UIImagePickerControllerEditedImage];
self.imageView.image  = img;
imagData         = UIImagePNGRepresentation(img);
[picker dismissViewControllerAnimated:YES completion:nil];
}

图像现在放置在图像视图中，我如何将图像保存在数据库中

我已经有数据库来插入数据 插入：

NSMutableArray *listItemsarr = [[NSMutableArray alloc] init];
        if([listItemsarr count]==0){
            NSString *insertQry=@"INSERT INTO selection_tbl (expenses_value,category,date,payment,description) VALUES(?,?,?,?,?)";
            sqlite3_stmt *stmt=[DB OpenSQL:[insertQry UTF8String]];
            if(stmt !=nil)
            {
                sqlite3_bind_text(stmt,1, [dataTextfield.text UTF8String], -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(stmt,2, [[selectionarray objectAtIndex:0]  UTF8String], -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(stmt,3, [[selectionarray objectAtIndex:1]  UTF8String], -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(stmt,4, [[selectionarray objectAtIndex:2]  UTF8String], -1, SQLITE_TRANSIENT);
                sqlite3_bind_text(stmt,5, [[selectionarray objectAtIndex:3]  UTF8String], -1, SQLITE_TRANSIENT);


                sqlite3_step(stmt);
            }
            sqlite3_finalize(stmt);
            [DB CloseSQL];

以下编码用于更新数据库值 更新：

NSInteger proeditid = [primarykeyID integerValue];
        NSString *updateQry=@"update selection_tbl set expenses_value=?,category=?,date=?,payment=?,description=? where expenses_id=?";
        sqlite3_stmt *stmt=[DB OpenSQL:[updateQry UTF8String]];
        if(stmt !=nil)
        {
            sqlite3_bind_text(stmt,1, [dataTextfield.text UTF8String], -1, SQLITE_TRANSIENT);
            sqlite3_bind_text(stmt,2, [[selectionarray objectAtIndex:0] UTF8String], -1, SQLITE_TRANSIENT);
            sqlite3_bind_text(stmt,3, [[selectionarray objectAtIndex:1] UTF8String], -1, SQLITE_TRANSIENT);
            sqlite3_bind_text(stmt,4, [[selectionarray objectAtIndex:2] UTF8String], -1, SQLITE_TRANSIENT);
            sqlite3_bind_text(stmt,5, [[selectionarray objectAtIndex:3] UTF8String], -1, SQLITE_TRANSIENT);


            sqlite3_bind_int(stmt,6, (int)proeditid);
            sqlite3_step(stmt);
        }
        sqlite3_finalize(stmt);
        [DB CloseSQL];

Answer 1

有两个问题：

1. 如何获取图片的NSData表示？

   • 简单的方法是使用UIImagePNGRepresentation 的UIImage。

   • 更好的方法是使用getBytes 来检索原始资产。见https://stackoverflow.com/a/25251943/1271826。

2. 如何将NSData 表示保存在 SQLite 数据库中？

   要将此NSData 保存在您的数据库中，然后使用sqlite3_bind_blob。该过程与您之前与我们共享的sqlite3_bind_xxx 函数非常相似。使用NSData 的bytes 方法访问指向缓冲区的C 样式指针，并将其传递给sqlite3_bind_blob。

请注意，在 SQLite 数据库中保存完整尺寸的图像是出了名的低效。 SQLite 不能很好地处理大块。通常，人们更愿意将NSData 保存到设备永久存储的Documents 文件夹中的文件中，然后将该文件的path 保存在数据库中。

Answer 2

在代码中添加以下行，将图像添加到数据库中

 sqlite3_bind_blob(stmt,6, [imagData bytes], (unsigned)[imagData length], SQLITE_TRANSIENT);

最终代码如下所示：

NSMutableArray *listItemsarr = [[NSMutableArray alloc] init];

            if([listItemsarr count]==0){
                NSString *insertQry=@"INSERT INTO selection_tbl (expenses_value,category,date,payment,description,image) VALUES(?,?,?,?,?,?)";
                sqlite3_stmt *stmt=[DB OpenSQL:[insertQry UTF8String]];
                if(stmt !=nil)
                {
                    sqlite3_bind_text(stmt,1, [dataTextfield.text UTF8String], -1, SQLITE_TRANSIENT);
                    sqlite3_bind_text(stmt,2, [[selectionarray objectAtIndex:0]  UTF8String], -1, SQLITE_TRANSIENT);
                    sqlite3_bind_text(stmt,3, [dateString  UTF8String], -1, SQLITE_TRANSIENT);
                    sqlite3_bind_text(stmt,4, [[selectionarray objectAtIndex:2]  UTF8String], -1, SQLITE_TRANSIENT);
                    sqlite3_bind_text(stmt,5, [[selectionarray objectAtIndex:3]  UTF8String], -1, SQLITE_TRANSIENT);
                    sqlite3_bind_blob(stmt,6, [imagData bytes], (unsigned)[imagData length], SQLITE_TRANSIENT);

                    sqlite3_step(stmt);
                }
                sqlite3_finalize(stmt);
                [DB CloseSQL];