从图片网址获取缩略图网址 [英] Get thumbnail URL from image URL

问题描述

我有一个String URL指向存储在设备外部存储中的图像:

I have a String URL pointing to an image stored on the external storage of my device:

String imageUrl = "/storage/emulated/0/DCIM/100MEDIA/IMAG0823.jpg"

我想查询 MediaStore 以获取此图像的缩略图.这就是我现在正在做的事情:

I want to get query the MediaStore to get the thumbnail for this image. This is what I do right now:

private String getImageThumbnailPath(Context ctx, String imageUrl){

    Cursor cursor = MediaStore.Images.Thumbnails.queryMiniThumbnails(
            ctx.getContentResolver(), Uri.fromFile(new File(imageUrl)),
            MediaStore.Images.Thumbnails.MICRO_KIND,
            null);

    String url = "";
    if( cursor != null && cursor.getCount() > 0 ) {
        cursor.moveToFirst();
        url = cursor.getString( cursor.getColumnIndex( MediaStore.Images.Thumbnails.DATA ) );
        cursor.close();
    }
    return url;
} 

但是，调用此方法并打印其内容不会显示任何内容(光标为空).

However, calling this method and printing it's content shows nothing (the cursor is empty).

如何在 MediaStore 中查询与我的图片网址相关联的缩略图网址?

How do I query the MediaStore for the thumbnail url associated with my image URL?

修改

我还尝试过直接从图片URL解析Uri，就像这样:

I've also tried to parse the Uri directly from the image URL, as so:

Cursor cursor = MediaStore.Images.Thumbnails.queryMiniThumbnails(
        ctx.getContentResolver(), Uri.parse(imageUrl),
        MediaStore.Images.Thumbnails.MINI_KIND,
        null);

但是结果是一样的.

推荐答案

如果您从图库中选择图像，以下代码将起作用，否则我们将无法创建缩略图，而必须创建缩略图.

Following code works if you have pick image from gallery, otherwise we can not have thumbnail, and we have to create thumbnail.

首先，您必须找到 MediaStore.Images.Media._ID

public String[] getRealPathFromURI(Uri contentUri) {
    String[] proj = { MediaStore.Images.Media.DATA,
            MediaStore.Images.Media._ID };
    Cursor cursor = getActivity().getContentResolver().query(contentUri,
            proj, null, null, null);
    int path_index = cursor.getColumnIndexOrThrow(proj[0]);
    int id_index = cursor.getColumnIndexOrThrow(proj[1]);
    cursor.moveToFirst();
    return new String[] { cursor.getString(path_index),
            cursor.getLong(id_index) + "" };
}

从上面的 getRealPathFromURI 上面，我们有了 MediaStore.Images.Media._ID ，请使用此ID查找缩略图.

From above getRealPathFromURI now we have MediaStore.Images.Media._ID, use this id to find thumbnail.

public static Bitmap getThumbnail(ContentResolver contentResolver, long id) {
        Cursor cursor = contentResolver.query(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                new String[]{MediaStore.Images.Media.DATA}, // Which columns
                // to return
                MediaStore.Images.Media._ID + "=?", // Which rows to return
                new String[]{String.valueOf(id)}, // Selection arguments
                null);// order

        if (cursor != null && cursor.getCount() > 0) {
            cursor.moveToFirst();
            String filePath = cursor.getString(0);
            cursor.close();
            int rotation = 0;
            try {
                ExifInterface exifInterface = new ExifInterface(filePath);
                int exifRotation = exifInterface.getAttributeInt(
                        ExifInterface.TAG_ORIENTATION,
                        ExifInterface.ORIENTATION_UNDEFINED);
                if (exifRotation != ExifInterface.ORIENTATION_UNDEFINED) {
                    switch (exifRotation) {
                        case ExifInterface.ORIENTATION_ROTATE_180:
                            rotation = 180;
                            break;
                        case ExifInterface.ORIENTATION_ROTATE_270:
                            rotation = 270;
                            break;
                        case ExifInterface.ORIENTATION_ROTATE_90:
                            rotation = 90;
                            break;
                    }
                }
            } catch (IOException e) {
                Log.e("getThumbnail", e.toString());
            }
            Bitmap bitmap = MediaStore.Images.Thumbnails.getThumbnail(
                    contentResolver, id,
                    MediaStore.Images.Thumbnails.MINI_KIND, null);
            if (rotation != 0) {
                Matrix matrix = new Matrix();
                matrix.setRotate(rotation);
                bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(),
                        bitmap.getHeight(), matrix, true);
            }
            return bitmap;
        } else
            return null;
    }

要在 LOC

已更新

String[] imageInfo = getRealPathFromURI(Uri.parse("YOUR_IMAGE_PATH"));
yourImageView.setImageBitmap(getThumbnail(getActivity()
                    .getContentResolver(), Long.parseLong(imageInfo[1])));

Uri.parse("YOUR_IMAGE_PATH")是contentUri

Uri.parse("YOUR_IMAGE_PATH") is contentUri

这篇关于从图片网址获取缩略图网址的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！