android - 在相机意图中选择图像大小

Question

我是这个论坛的新手，所以请多多包涵，如果有错误，请轻轻指出，所以我正在做一个将图像上传到服务器的项目，现在我想限制图像的大小，我' m 提供“单击图像”选项，我的代码将打开默认相机意图并单击图片，或“从图库中选择”。我的问题是关于“点击图片”，现在当用户点击图片时，我可以预设可以点击的图片最大尺寸吗？

标签： androidandroid-studioandroid-camera-intent

Answer 1

您可以在 onActivityResult 方法中调整图像大小，尝试以下代码片段

 public static Bitmap handleSamplingAndRotationBitmap(Context context, Uri selectedImage)
            throws IOException {
        int MAX_HEIGHT = 1024;
        int MAX_WIDTH = 1024;
        // First decode with inJustDecodeBounds=true to check dimensions
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        InputStream imageStream = context.getContentResolver().openInputStream(selectedImage);
        BitmapFactory.decodeStream(imageStream, null, options);
        imageStream.close();
        options.inSampleSize = calculateInSampleSizes(options, MAX_WIDTH, MAX_HEIGHT);
        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;
        imageStream = context.getContentResolver().openInputStream(selectedImage);
        Bitmap img = BitmapFactory.decodeStream(imageStream, null, options);
        img = rotateImageIfRequired(context, img, selectedImage);
        return img;
    }

    private static int calculateInSampleSizes(BitmapFactory.Options options,
                                             int reqWidth, int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {

            // Calculate ratios of height and width to requested height and width
            final int heightRatio = Math.round((float) height / (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);

            // Choose the smallest ratio as inSampleSize value, this will guarantee a final image
            // with both dimensions larger than or equal to the requested height and width.
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;

            // This offers some additional logic in case the image has a strange
            // aspect ratio. For example, a panorama may have a much larger
            // width than height. In these cases the total pixels might still
            // end up being too large to fit comfortably in memory, so we should
            // be more aggressive with sample down the image (=larger inSampleSize).

            final float totalPixels = width * height;

            // Anything more than 2x the requested pixels we'll sample down further
            final float totalReqPixelsCap = reqWidth * reqHeight * 2;

            while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
                inSampleSize++;
            }
        }
        return inSampleSize;
    }
    private static Bitmap rotateImageIfRequired(Context context, Bitmap img, Uri selectedImage) throws IOException {

        InputStream input = context.getContentResolver().openInputStream(selectedImage);
        ExifInterface ei;
        if (Build.VERSION.SDK_INT > 23)
            ei = new ExifInterface(input);
        else
            ei = new ExifInterface(selectedImage.getPath());

        int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

        switch (orientation) {
            case ExifInterface.ORIENTATION_ROTATE_90:
                return rotateImage(img, 90);
            case ExifInterface.ORIENTATION_ROTATE_180:
                return rotateImage(img, 180);
            case ExifInterface.ORIENTATION_ROTATE_270:
                return rotateImage(img, 270);
            default:
                return img;
        }
    }
    private static Bitmap rotateImage(Bitmap img, int degree) {
        Matrix matrix = new Matrix();
        matrix.postRotate(degree);
        Bitmap rotatedImg = Bitmap.createBitmap(img, 0, 0, img.getWidth(), img.getHeight(), matrix, true);
        img.recycle();
        return rotatedImg;
    }

你只需要调用handleSamplingAndRotationBitmap方法，你会得到一个可以自己设置大小的位图。PS: 案例 sumsung 手机旋转拍摄的一些图片是不正确的，所以我们也需要处理图片的方向，希望可以帮助你。