拍照并转换为Base64

Question

我使用下面的代码用相机拍照。而不是保存我想将其编码为Base64，然后将其作为输入传递给另一个API。我无法看到方法，如何修改代码以在Base64而不是常规文件中拍照。

public class CameraDemoActivity extends Activity {
    int TAKE_PHOTO_CODE = 0;
    public static int count = 0;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        final String dir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES) + "/picFolder/";
        File newdir = new File(dir);
        newdir.mkdirs();

        Button capture = (Button) findViewById(R.id.btnCapture);
        capture.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                count++;
                String file = dir+count+".jpg";
                File newfile = new File(file);
                try {
                    newfile.createNewFile();
                }
                catch (IOException e)
                {
                }

                Uri outputFileUri = Uri.fromFile(newfile);

                Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);

                startActivityForResult(cameraIntent, TAKE_PHOTO_CODE);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == TAKE_PHOTO_CODE && resultCode == RESULT_OK) {
            Log.d("CameraDemo", "Pic saved");
        }
    }
}

我尝试使用下面的代码将图片转换为Base64。

public static String encodeToBase64(Bitmap image, Bitmap.CompressFormat compressFormat, int quality)
{
    ByteArrayOutputStream byteArrayOS = new ByteArrayOutputStream();
    image.compress(compressFormat, quality, byteArrayOS);
    return Base64.encodeToString(byteArrayOS.toByteArray(), Base64.DEFAULT);
}

上述描述应该比保存图像更直接，更简单，然后寻找图像进行编码。

Answer 1

试试这个：
  ImageUri到位图：

a

在base64中编码位图

ClassB

从FilePath编码到base64

 @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);

            if (requestCode == TAKE_PHOTO_CODE && resultCode == RESULT_OK) {
                final Uri imageUri = data.getData();
                final InputStream imageStream = getContentResolver().openInputStream(imageUri);
                final Bitmap selectedImage = BitmapFactory.decodeStream(imageStream);
                String encodedImage = encodeImage(selectedImage);
            }
        }

输出：

Answer 2

如果您希望base64字符串遵循标准格式，请在从提供的任何答案中获取base64方法后添加此

String base64 =""; //Your encoded string
base64 = "data:image/"+getMimeType(context,profileUri)+";base64,"+base64;

获取imageExtension的方法是

   public static String getMimeType(Context context, Uri uri) {
        String extension;
        if (uri.getScheme().equals(ContentResolver.SCHEME_CONTENT)) {
            //If scheme is a content
            final MimeTypeMap mime = MimeTypeMap.getSingleton();
            extension = mime.getExtensionFromMimeType(context.getContentResolver().getType(uri));
        } else {
            //If scheme is a File
            //This will replace white spaces with %20 and also other special characters. This will avoid returning null values on file name with spaces and special characters.
            extension = MimeTypeMap.getFileExtensionFromUrl(Uri.fromFile(new File(uri.getPath())).toString());
        }
        return extension;
    }

Answer 3

我写了这样的代码：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Camera mCamera = Camera.open();
        mCamera.startPreview();// I don't know why I added that, 
                               // but without it doesn't work... :D

        mCamera.takePicture(null, null, mPicture);
    }

    private Camera.PictureCallback mPicture = new Camera.PictureCallback() {

        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            System.out.println("***************");
            System.out.println(Base64.encodeToString(data, Base64.DEFAULT));
            System.out.println("***************");
        }
    };
}

完美无缺......

Answer 4

我只是使用Kotlin中的从位图转换为base64字符串而已：

private fun encodeImage(bm: Bitmap): String? {
        val baos = ByteArrayOutputStream()
        bm.compress(Bitmap.CompressFormat.JPEG, 100, baos)
        val b = baos.toByteArray()
        return Base64.encodeToString(b, Base64.DEFAULT)
    }