拍照并转换为Base64

Question

我使用下面的代码用相机拍照。我不想保存，而是想将其编码为 Base64，然后将其作为输入传递给另一个 API。我看不到方法，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像转换为 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);
}

上面描述的应该是比保存图像然后再寻找图像进行编码更直接和更容易的方法。

Answer 1

试试这个：
ImageUri 转位图:

 @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);
            }
        }

在 base64 中编码位图

   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);

        return encImage;
    }

从 FilePath 编码为 base64

 private String encodeImage(String path)
    {
        File imagefile = new File(path);
        FileInputStream fis = null;
        try{
            fis = new FileInputStream(imagefile);
        }catch(FileNotFoundException e){
            e.printStackTrace();
        }
        Bitmap bm = BitmapFactory.decodeStream(fis);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bm.compress(Bitmap.CompressFormat.JPEG,100,baos);
        byte[] b = baos.toByteArray();
        String encImage = Base64.encodeToString(b, Base64.DEFAULT);
        //Base64.de
        return encImage;

    }

输出：

Answer 2

我的代码是这样写的：

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("***************");
        }
    };
}

完美运行...

Answer 3

只是为了在 kotlin 中从位图转换为 base64 字符串，我使用：

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)
    }

Answer 4

如果您希望您的 base64 字符串遵循标准格式，请在从任何提供的答案中获取您的 base64 方法后添加此内容

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;
    }

拍照并转换为Base64

Take picture and convert to Base64

base64

android

bitmap

android-camera