在将Base64字符串解码为图像时，我得到一个完全黑色的图像

Question

我已经使用此功能对图像进行编码。

private String encodeImage(Bitmap bm)
        {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            bm.compress(Bitmap.CompressFormat.JPEG,100,baos);
            byte[] b = baos.toByteArray();
            String encImage = Base64.encodeToString(b, Base64.DEFAULT);
            Log.d(TAG, "encodeImage: " + encImage);
            return encImage;
        }

这是我创建位图图像的方式

setContentView(R.layout.camera);
        cameraView = (CameraView) findViewById(cameras);
        cameraView.setJpegQuality(2);
        cameraView.setCameraListener(new CameraListener() {
            @Override
            public void onPictureTaken(byte[] jpeg) {
                super.onPictureTaken(jpeg);

                Bitmap bitmap = BitmapFactory.decodeByteArray(jpeg, 0, jpeg.length);
                encodeImage(bitmap);
            }
        });

在使用在线工具解码由此生成的byte64字符串时，我得到一个完全黑色的图像。

这是我的byte64字符串

/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEB
AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQH/2wBDAQEBAQEBAQEBAQEBAQEBAQEBAQEB
AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQH/wAARCBIACiADASIA
AhEBAxEB/8QAHwAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQA
AAF9AQIDAAQRBRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3
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AwEBAQEBAQEBAQAAAAAAAAECAwQFBgcICQoL/8QAtREAAgECBAQDBAcFBAQAAQJ3AAECAxEEBSEx
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8de61KPNijI8vrxz3+Yjpk8c9D74yDX5OfUCqsMgjkjgi83z+J57c+rn2yDz7A8c5zUUatHMfKSK
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Answer 1

您的编码代码没问题，只需检查一下。尝试从logcat复制编码字符串时，很有可能出错。只需在Log.d()上放置断点，复制编码的字符串值并通过在线工具再次检出。我使用this来测试结果。

Answer 2

我不在Android中编码，但我认为您正在混合数据。例如，manual表示Bitmap bitmap = BitmapFactory.decodeByteArray(jpeg, 0, jpeg.length); 将“从指定的字节数组中解码不可变位图。”所以这一行：

jpeg

仅当encImage数组包含原始RGB颜色值而非实际JPEG值时才起作用（因为JPEG是压缩数学而不是颜色数组）。

试试这个，看看某些online tool是否可以显示字符串 private String encodeImage(Bitmap bm)。没有使用其他函数setContentView(R.layout.camera); cameraView = (CameraView) findViewById(cameras); cameraView.setPictureFormat(ImageFormat.JPEG); cameraView.setJpegQuality(2); cameraView.setCameraListener(new CameraListener() { @Override public void onPictureTaken(byte[] jpeg) { super.onPictureTaken(jpeg); String encImage = Base64.encodeToString(jpeg, Base64.DEFAULT); //print and test this string in some B64-to-JPEG decoder/viewer //Bitmap bitmap = BitmapFactory.decodeByteArray(jpeg, 0, jpeg.length); //encodeImage(bitmap); } }); ，因为我怀疑它是问题的一部分......

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