Android如何将图像保存在SD卡上，调整大小并再次保存？

我有一个问题，我正在使用以下代码拍照：

private void captureImage() {
            Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

            fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);

            intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);

            // start the image capture Intent
            startActivityForResult(intent, CAMERA_CAPTURE_IMAGE_REQUEST_CODE);
        }

创建fileUri的函数如下所示：

public Uri getOutputMediaFileUri(int type) {
            return Uri.fromFile(getOutputMediaFile(type));
        }

        /*
         * returning image / video
         */
        private static File getOutputMediaFile(int type) {

            // External sdcard location
            File mediaStorageDir = new File(
                    Environment
                            .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
                    IMAGE_DIRECTORY_NAME);

            // Create the storage directory if it does not exist
            if (!mediaStorageDir.exists()) {
                if (!mediaStorageDir.mkdirs()) {
                    Log.d(IMAGE_DIRECTORY_NAME, "Creación fallida "
                            + IMAGE_DIRECTORY_NAME + " directory");
                    return null;
                }
            }

            // Create a media file name
            String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
                    Locale.getDefault()).format(new Date());
            File mediaFile;
            if (type == MEDIA_TYPE_IMAGE) {
                mediaFile = new File(mediaStorageDir.getPath() + File.separator
                        + "IMGTRAF_" + timeStamp + ".jpg");
            } else if (type == MEDIA_TYPE_VIDEO) {
                mediaFile = new File(mediaStorageDir.getPath() + File.separator
                        + "VIDTRAF_" + timeStamp + ".mp4");
            } else {
                return null;
            }

            return mediaFile;
        }

在这里，我在ImageView上显示图像：

@Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            // if the result is capturing Image
            if (requestCode == CAMERA_CAPTURE_IMAGE_REQUEST_CODE) {
                if (resultCode == RESULT_OK) {
                    // successfully captured the image
                    // display it in image view
                    previewCapturedImage();
                    Toast.makeText(getApplicationContext(),
                            "Mostrando foto", Toast.LENGTH_SHORT)
                            .show();
                } else if (resultCode == RESULT_CANCELED) {
                    // user cancelled Image capture
                    Toast.makeText(getApplicationContext(),
                            "Acción cancelada", Toast.LENGTH_SHORT)
                            .show();
                } else {
                    // failed to capture image
                    Toast.makeText(getApplicationContext(),
                            "Error al capturar la imagen", Toast.LENGTH_SHORT)
                            .show();
                }
            } else if (requestCode == CAMERA_CAPTURE_VIDEO_REQUEST_CODE) {
                if (resultCode == RESULT_OK) {
                    // video successfully recorded
                    // preview the recorded video
                    previewVideo();
                    Toast.makeText(getApplicationContext(),
                            "Reproduciendo video", Toast.LENGTH_SHORT)
                            .show();
                } else if (resultCode == RESULT_CANCELED) {
                    // user cancelled recording
                    Toast.makeText(getApplicationContext(),
                            "Acción cancelada", Toast.LENGTH_SHORT)
                            .show();
                } else {
                    // failed to record video
                    Toast.makeText(getApplicationContext(),
                            "Error al capturar el video", Toast.LENGTH_SHORT)
                            .show();
                }
            }
        }

        /*
         * Display image from a path to ImageView
         */
        private void previewCapturedImage() {
            try {
                // hide video preview
                videoPreview.setVisibility(View.GONE);

                imgPreview.setVisibility(View.VISIBLE);

                // bimatp factory
                BitmapFactory.Options options = new BitmapFactory.Options();

                // downsizing image as it throws OutOfMemory Exception for larger
                // images
                options.inSampleSize = 8;

                final Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(),
                        options);

                imgPreview.setImageBitmap(bitmap);
            } catch (NullPointerException e) {
                e.printStackTrace();
            }
        }

问题是，当我拍摄图像时，它是以原始大小（1954*2560）保存的，而当我将其上传到服务器时，需要很长时间。我在这里看到了很多问题和答案，但没有一个对我有用。我想拍摄照片，将其大小调整为800x600，然后再次保存，以便将其上载到服务器

我怎样才能做到这一点？请考虑我对Android编程非常陌生。

谢谢

最后，我通过以下操作解决了问题：

private void previewCapturedImage() {
            try {
                // hide video preview
                videoPreview.setVisibility(View.GONE);

                imgPreview.setVisibility(View.VISIBLE);

                // bimatp factory
                BitmapFactory.Options options = new BitmapFactory.Options();

                // downsizing image as it throws OutOfMemory Exception for larger
                // images
                options.inSampleSize = 8;

                final Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(),
                        options);

                File mediaStorageDir = new File(
                        Environment
                                .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
                        IMAGE_DIRECTORY_NAME);

                String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
                        Locale.getDefault()).format(new Date());
                File file;
                file = new File(fileUri.getPath());
                try {
                    FileOutputStream out = new FileOutputStream(file);
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
                    out.flush();
                    out.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }

                //fileUri = file;

                imgPreview.setImageBitmap(bitmap);
            } catch (NullPointerException e) {
                e.printStackTrace();
            }
        }

我希望它能在不久的将来帮助别人。

解决了这个问题：

private void previewCapturedImage() {
            try {
                // hide video preview
                videoPreview.setVisibility(View.GONE);

                imgPreview.setVisibility(View.VISIBLE);

                // bimatp factory
                BitmapFactory.Options options = new BitmapFactory.Options();

                // downsizing image as it throws OutOfMemory Exception for larger
                // images
                options.inSampleSize = 8;

                final Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(),
                        options);

                File mediaStorageDir = new File(
                        Environment
                                .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
                        IMAGE_DIRECTORY_NAME);

                String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
                        Locale.getDefault()).format(new Date());
                File file;
                file = new File(fileUri.getPath());
                try {
                    FileOutputStream out = new FileOutputStream(file);
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
                    out.flush();
                    out.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }

                //fileUri = file;

                imgPreview.setImageBitmap(bitmap);
            } catch (NullPointerException e) {
                e.printStackTrace();
            }
        }

---

您可以在上载之前调整图像的大小。。上传前读取图像的代码在哪里？谢谢您的回答，这是我发布的最后一段代码中的previewCapturedImage（）函数。