Question

我试图在抖动中转换图像文件：

 File _img=new File('/data/user/0/com.example.test3/app_flutter/2020-10-29T17:18:56.210347.png');
 List<int> imageBytes = _img.readAsBytesSync();
 String imageB64 = base64Encode(imageBytes);
 print(imageB64);

但是它看起来像是错误的base64字符串，我无法在转换网站上解码为图像： https://codebeautify.org/base64-to-image-converter

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

dart base64格式是否与另一种格式不同？谢谢。

Answer 1

您必须将字节转换为Uint8List对象，而不是List<int>：

File _img = File(
   '/data/user/0/com.example.test3/app_flutter/2020-10-29T17:18:56.210347.png');
final bytes = Uint8List.fromList(_img.readAsBytesSync());
final imgBase64 = base64Encode(bytes);
print(imgBase64);

Answer 2

我发现通过'print'功能的这种情况无法显示完整的base64代码。如果要验证，则需要导出到文本文件：

Private Sub WebBrowser1_DocumentCompleted(sender As Object, e As WebBrowserDocumentCompletedEventArgs)
    Dim message = "{\""action\"":\""loadReport\"",\""accessToken\"":\""" & tKn & """\,""id\"":\""" & ReportID & """\,""\groupId\"":\""" & tenantID & """\,""\tokenType\"":""\models.TokenType.Embed\""}"
 WebBrowser1.Document.InvokeScript("postMessage", New Object() {message, "*"})
End Sub

如何在flutter中将图像文件转换为base64字符串？

2 个答案: