在android应用程序中上传pdf或txt并转换为base64

我正在为一个应用程序工作，我需要上传一个文件（来自相机或画廊的图像，来自文档的pdf或txt），在base64中转换，并在数组中添加带有base64的字符串。我解决了从相机和画廊的图像-现在我需要做同样的文件。如何将文档从设备上载到应用程序并在base64中转换？这是我的图像代码：

private void selectImage(){

    final CharSequence[] item={"Camera","Document","Cancel"};

    AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
    builder.setTitle("Carica");
    builder.setItems(item, new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int i) {
            if(item[i].equals("Camera")){
                Intent intent= new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                startActivityForResult(intent,Request_camera);
            }
            else if(item[i].equals("Document")){

                Intent intent3 = new Intent();
                intent3.setType("*/*");
                intent3.setAction(Intent.ACTION_GET_CONTENT);
                startActivityForResult(Intent.createChooser(intent3,"Choose File to Upload.."),PICK_FILE_REQUEST);
                Uri.parse(Environment.getExternalStorageDirectory().toString());


            }

            else if(item[i].equals("Cancel")){
                dialog.dismiss();
            }
        }
    }).show();
}

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

    if(resultCode== Activity.RESULT_OK){
        if(requestCode==Request_camera && button1==1){

            Bundle bundle=data.getExtras();
            final Bitmap bpm= (Bitmap)bundle.get("data");
            uploadImage.setImageBitmap(bpm);
            bitmapToBase64(bpm);

            String mynewString=bitmapToBase64(bpm);
            mydocument.set(0,mynewString);
            decode64.setText(mynewString);
            getFileExt(uploadImage.toString());

        }
         else if(requestCode==Request_camera && button1==2){
            Bundle bundle=data.getExtras();
            final Bitmap bpm= (Bitmap)bundle.get("data");
            imageView2.setImageBitmap(bpm);
            bitmapToBase64(bpm);

            String mynewString=bitmapToBase64(bpm);
            decodee2.setText(mynewString);
            decodee2.setTextColor(Color.GREEN);
        }

        else if(requestCode==Request_file){
            Uri selectImageUri=data.getData();
            uploadImage.setImageURI(selectImageUri);
            String newNome=getFileName(selectImageUri);
            decode64.setText(newNome);

            String realPath=selectImageUri.toString();

            decodee2.setText(realPath);

            File file=new File(newNome);

            getStringFile(file);
            String myDecode=getStringFile(file);
            mydocument.set(0,myDecode);


        }
    }

}


private String bitmapToBase64(Bitmap bitmap) {
    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, byteArrayOutputStream);
    byte[] byteArray = byteArrayOutputStream .toByteArray();
    return Base64.encodeToString(byteArray, Base64.DEFAULT);
}

---

谢谢

将图像转换为Base64

private  String imageToString(Bitmap bitmap){
    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, byteArrayOutputStream);
    byte[] imageByte = byteArrayOutputStream.toByteArray();
    return Base64.encodeToString(imageByte, Base64.DEFAULT);
}

您需要首先将其转换为位图