如何在Android上传到服务器之前调整/压缩相机图像或图库图像？

Question

我需要上传一张图片，这个图片可以从相册中选择或者通过相机拍摄。我已经成功地完成了这项任务。但是问题在于，有时候这个图片的大小会达到1MB。因此，在上传到服务器之前，我需要对这个图片进行缩小。如何实现呢？

 public void onActivityResult(int requestCode, int resultCode, Intent data)
{
    AlertDialog alertDialog1;

    if( requestCode == REQUEST_IMAGE && resultCode == Activity.RESULT_OK ){
        try {
            FileInputStream in = new FileInputStream(destination);
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inSampleSize = 10;
            imagePath = destination.getAbsolutePath();
            Bitmap bmp = BitmapFactory.decodeStream(in, null, options);
            //img = (ImageView) findViewById(R.id.imageView1);
            int nh = (int) ( bmp.getHeight() * (512.0 / bmp.getWidth()) );
            Bitmap scaled = Bitmap.createScaledBitmap(bmp, 512, nh, true);
            img.setImageBitmap(scaled);
        } catch (Exception e) {
            // AlertDialog alertDialog1;
            alertDialog1 = new AlertDialog.Builder(getActivity()).create();
            alertDialog1.setTitle("Message");
            alertDialog1.setMessage("bala \t "+e.toString());
            alertDialog1.show();
        }

    }else if (requestCode == 1) {
        try {
            Uri selectedImageUri = data.getData();
            imagePath =  getPath(selectedImageUri);
            destination = new File(imagePath);
            FileInputStream in = new FileInputStream(destination);
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inSampleSize = 10;
            imagePath = destination.getAbsolutePath();
            Bitmap bmp = BitmapFactory.decodeStream(in, null, options);
            //int nh = (int) ( bmp.getHeight() * (512.0 / bmp.getWidth()) );
           // Bitmap scaled = Bitmap.createScaledBitmap(bmp, 512, nh, true);
            img.setImageBitmap(bmp);

            //img.setImageBitmap(bmp);
        } catch (Exception e) {
            // AlertDialog alertDialog1;
            alertDialog1 = new AlertDialog.Builder(getActivity()).create();
            alertDialog1.setTitle("Message");
            alertDialog1.setMessage("sang\t"+e.toString());
            alertDialog1.show();
        }
    }
    else{

    }
}

现在，如何调整图像的大小？

- The Bala

---

可能是从相册或相机获取图片并上传前调整大小的问题的重复。 - Iamat8

如何在Android中调整图像大小 - Haven

Answer 1

1. 要调整图像大小，您可以使用以下函数

   Bitmap yourBitmap; Bitmap resized = Bitmap.createScaledBitmap(yourBitmap, newWidth, newHeight, true);

2. 要压缩图像

   Bitmap bmp = BitmapFactory.decodeFile(miFoto) ByteArrayOutputStream bos = new ByteArrayOutputStream(); bmp.compress(CompressFormat.JPEG, 70, bos); InputStream in = new ByteArrayInputStream(bos.toByteArray()); ContentBody foto = new InputStreamBody(in, "image/jpeg", "filename");

- Nishant

---

你能提供完整的代码吗？在我的代码中应该在哪里使用这段代码？ - The Bala

Answer 2

您可以检查此代码，它与您想要的相同WhatsApp Like Image Compression。此代码已根据我的使用进行了修改。 使用此代码将为您提供：

-大小为 100kb 的低大小图像，而无需调整图像质量。 -高像素图像将缩小到 maxWidth 和 maxHeight ，而不会失去其原始质量。

原始文章：像WhatsApp一样超快速加载图像 演示：

-原始图像：大小-3.84Mb尺寸-3120 * 4160 -压缩图像：大小-157Kb尺寸-960 * 1280

- Vipul Asri

Answer 3

你需要压缩图片，因为重新调整位图会降低图像质量。你可以尝试使用这个函数来压缩你的图片。只需从活动中上传图片时传递此函数即可。

/ Funtion for compress image
    public String compressImage(String imageUri) {

        String filePath = getRealPathFromURI(imageUri);
        Bitmap scaledBitmap = null;

        BitmapFactory.Options options = new BitmapFactory.Options();

//      by setting this field as true, the actual bitmap pixels are not loaded in the memory. Just the bounds are loaded. If
//      you try the use the bitmap here, you will get null.
        options.inJustDecodeBounds = true;
        Bitmap bmp = BitmapFactory.decodeFile(filePath, options);

        int actualHeight = options.outHeight;
        int actualWidth = options.outWidth;

//      max Height and width values of the compressed image is taken as 816x612

        float maxHeight = 816.0f;
        float maxWidth = 612.0f;
        float imgRatio = actualWidth / actualHeight;
        float maxRatio = maxWidth / maxHeight;

//      width and height values are set maintaining the aspect ratio of the image

        if (actualHeight > maxHeight || actualWidth > maxWidth) {
            if (imgRatio < maxRatio) {               imgRatio = maxHeight / actualHeight;                actualWidth = (int) (imgRatio * actualWidth);               actualHeight = (int) maxHeight;             } else if (imgRatio > maxRatio) {
                imgRatio = maxWidth / actualWidth;
                actualHeight = (int) (imgRatio * actualHeight);
                actualWidth = (int) maxWidth;
            } else {
                actualHeight = (int) maxHeight;
                actualWidth = (int) maxWidth;

            }
        }

//      setting inSampleSize value allows to load a scaled down version of the original image

        options.inSampleSize = calculateInSampleSize(options, actualWidth, actualHeight);

//      inJustDecodeBounds set to false to load the actual bitmap
        options.inJustDecodeBounds = false;

//      this options allow android to claim the bitmap memory if it runs low on memory
        options.inPurgeable = true;
        options.inInputShareable = true;
        options.inTempStorage = new byte[16 * 1024];

        try {
//          load the bitmap from its path
            bmp = BitmapFactory.decodeFile(filePath, options);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();

        }
        try {
            scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight,Bitmap.Config.ARGB_8888);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();
        }

        float ratioX = actualWidth / (float) options.outWidth;
        float ratioY = actualHeight / (float) options.outHeight;
        float middleX = actualWidth / 2.0f;
        float middleY = actualHeight / 2.0f;

        Matrix scaleMatrix = new Matrix();
        scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);

        Canvas canvas = new Canvas(scaledBitmap);
        canvas.setMatrix(scaleMatrix);
        canvas.drawBitmap(bmp, middleX - bmp.getWidth() / 2, middleY - bmp.getHeight() / 2, new Paint(Paint.FILTER_BITMAP_FLAG));

//      check the rotation of the image and display it properly
        ExifInterface exif;
        try {
            exif = new ExifInterface(filePath);

            int orientation = exif.getAttributeInt(
                    ExifInterface.TAG_ORIENTATION, 0);
            Log.d("EXIF", "Exif: " + orientation);
            Matrix matrix = new Matrix();
            if (orientation == 6) {
                matrix.postRotate(90);
                Log.d("EXIF", "Exif: " + orientation);
            } else if (orientation == 3) {
                matrix.postRotate(180);
                Log.d("EXIF", "Exif: " + orientation);
            } else if (orientation == 8) {
                matrix.postRotate(270);
                Log.d("EXIF", "Exif: " + orientation);
            }
            scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0, scaledBitmap.getWidth(), scaledBitmap.getHeight(), matrix, true);
        } catch (IOException e) {
            e.printStackTrace();
        }

        FileOutputStream out = null;
        String filename = getFilename();
        try {
            out = new FileOutputStream(filename);

//          write the compressed bitmap at the destination specified by filename.
            scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

        return filename;

    }


    public String getFilename() {
        File file = new File(Environment.getExternalStorageDirectory().getPath(), "MyFolder/Images");
        if (!file.exists()) {
            file.mkdirs();
        }
        String uriSting = (file.getAbsolutePath() + "/" + System.currentTimeMillis() + ".jpg");
        return uriSting;

    }

    private String getRealPathFromURI(String contentURI) {
        Uri contentUri = Uri.parse(contentURI);
        Cursor cursor = getContentResolver().query(contentUri, null, null, null, null);
        if (cursor == null) {
            return contentUri.getPath();
        } else {
            cursor.moveToFirst();
            int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
            return cursor.getString(index);
        }
    }

    public int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            final int heightRatio = Math.round((float) height/ (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;      }       final float totalPixels = width * height;       final float totalReqPixelsCap = reqWidth * reqHeight * 2;       while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
            inSampleSize++;
        }

        return inSampleSize;
    }

    //
    private void previewMedia(boolean isImage) {


        // Checking whether captured media is image or video
        if (isImage) {
            photo.setVisibility(View.VISIBLE);
            // vidPreview.setVisibility(View.GONE);
            // bimatp factory
            BitmapFactory.Options options = new BitmapFactory.Options();


            // down sizing image as it throws OutOfMemory Exception for larger
            // images
            options.inSampleSize = 2;


            final Bitmap bitmap = BitmapFactory.decodeFile(filePath, options);
            options.inJustDecodeBounds = true;


            photo.setImageBitmap(bitmap);

        }


    }

- user4751306

Answer 4

像压缩位图一样

bmp = Bitmap.createScaledBitmap(bmp, 160, 160, true);

- Damini Mehra

---

它没有起作用。原始图像大小为867kb，缩放后的图像也相同。 - The Bala

Answer 5

可以使用：

Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath());
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 50, stream); //compress to 50% of original image quality
byte[] byte_arr = stream.toByteArray();

- rafsanahmad007