Android base64解码xamarin中的bad base64错误

Question

我正在尝试将此base64解码为drawable

`data:image/jpg;base64,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`

这是我的代码

byte[] decodedByte = Android.Util.Base64.Decode(Config.Base64Photo, Android.Util.Base64Flags.NoPadding);
 var _bitmap = Android.Graphics.BitmapFactory.DecodeByteArray(decodedByte, 0, decodedByte.Length);
 var _drawable = new Android.Graphics.Drawables.BitmapDrawable(_bitmap );
avatarView.SetImageDrawable(_drawable);

如果我使用

byte[] decodedByte = Android.Util.Base64.Decode(Config.Base64Photo, Android.Util.Base64Flags.NoPadding

我的基础变坏了

如果我使用

byte[] decodedByte = Android.Util.Base64.Decode(Config.Base64Photo, Android.Util.Base64Flags.UrlSafe

我得到_bitmap变量为null

如何将此base64解码为位图？

Answer 1

你的base64字符串在data:image/jpg;base64,之后开始。所以你的代码应该类似于这个

var buf = Convert.FromBase64String(base64.Substring(base64.IndexOf(',') + 1));

您的图片是：

c＃中的完整代码

var buf = Convert.FromBase64String(base64.Substring(base64.IndexOf(',') + 1));
var bmp = Bitmap.FromStream(new MemoryStream(buf));
bmp.Save(@"a.bmp", System.Drawing.Imaging.ImageFormat.Bmp);