圖片是由UIImagePickerControllerSourceTypeCamera拍攝的，如何將其保存在ios中的數據庫中

Question

.m編碼

-(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];
}

現在將圖像放置在圖像視圖中，如何將圖像保存在數據庫中

我已經有數據庫要插入要插入的數據：

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];

以下代碼用於更新要更新的數據庫值：

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

有兩個問題：

1. 如何獲取圖像的NSData表示形式？

   • 簡單的方法是使用UIImage UIImagePNGRepresentation 。

   • 更好的方法是使用getBytes檢索原始資產。 參見https://stackoverflow.com/a/25251943/1271826

2. 如何將NSData表示形式保存在SQLite數據庫中？

   要將此NSData保存在數據庫中，請使用sqlite3_bind_blob 。 該過程與您之前與我們共享的sqlite3_bind_xxx函數非常相似。 使用NSData的bytes方法訪問指向緩沖區的C樣式指針，並將其傳遞給sqlite3_bind_blob 。

注意，在SQLite數據庫中保存完整大小的圖像效率極低。 SQLite不能很好地處理大型Blob。 一般人寧願保存NSData進入對設備的持久存儲的文檔文件夾中的文件，然后只保存path在數據庫中的文件。

Answer 2

在代碼中添加以下行，這將在數據庫中添加圖像

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

最終代碼如下所示：

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];