将颤振图像对象转换为文件对象以在服务器上发送

Question

我是 Flutter 的新手，我有一个签名板返回的图像对象，我想将其发送到接受文件的服务器，所以我如何将此对象发送到服务器。或者我们如何在flutter中将此图像对象转换为文件。

Image _sign;
File _uplodfile;
final data = await signatureGlobalKey.currentState.toImage(pixelRatio: 3.0);
final bytes = await data.toByteData(format: ui.ImageByteFormat.png);

if (data != null) {
  setState(() {
    _sign = Image.memory(bytes.buffer.asUint8List());
  });

Answer 1

您可以使用flutter_uploader。

先存入手机，再转成文件发到服务器。

final data = await signatureGlobalKey.currentState.toImage(pixelRatio: 3.0);
var savedDir = await getApplicationDocumentsDirectory();
String appDocPath = savedDir.path;

await Directory('$appDocPath/Signature/').create(recursive: true);
var file ='$appDocPath/image/${DateUtil().signformattedDate()}.png';
File(file).writeAsBytesSync(bytes.buffer.asInt8List());

submitToServer(file);

submitToServer

void submitToServer(String file) async {
    var savedDir = await getApplicationDocumentsDirectory();
    String appDocPath = savedDir.path;
    var filename = FileUtils.basename(file);
    final taskId = await uploader.enqueue(
        url: "your upload link",
        files: [
          FileItem(filename: filename, savedDir: appDocPath, fieldname: "file")
        ],
        method: UploadMethod.POST,
        headers: {"apikey": "api_123456", "userkey": "userkey_123456"},
        data: {"name": "john"}, // any data you want to send in upload request
        showNotification:
            false, // send local notification (android only) for upload status
        tag: "upload 1"); // unique tag for upload task
  }