How to priorly get future Glide image size which will be stored in cache in Android/Java?

问题

In MainActivity, I'm loading some images using glide into recyclerview according to imageview size.

See:

 @Override
    public void onBindViewHolder(PreviewAdapter.MyViewHolder holder, int position) {
        Glide.with(context).load(previewArrayList.get(position).getUrl()).diskCacheStrategy(DiskCacheStrategy.AUTOMATIC).into(holder.postImage);
}

XML:

<ImageView
    android:id="@+id/post_image"
    android:layout_width="match_parent"
    android:layout_marginTop="4dp"
    android:layout_height="250dp"
    android:layout_below="@+id/post_name"
    android:scaleType="centerCrop" />

As you can observe, I'm using Glide cache DiskCacheStrategy.AUTOMATIC also so that next time without Internet Glide can show the images. Now you can read in this post https://medium.com/@multidots/glide-vs-picasso-930eed42b81d that " Glide resizes the image as per the dimension of the ImageView."

Now, I want that final size inside SpalshActivity, which Glide will be stored in cache. So that when After SpalshActivity, when user opens MainActivity without Internet Conncetion for the very first time also, then it should load Images.

So how is it possible?

In SpalshActivity, I'm already caching Images, but it is again downloading/resizing in MainActivity for the very first time.

SpalshActivity:

private void preloadImage(String url) {
        try {

            //File file = Glide.with(this).asFile().load(url).submit().get();
            //String path = file.getPath();


            Glide.with(this)
                    .load(url)
                    .diskCacheStrategy(DiskCacheStrategy.ALL)
                    .listener(new RequestListener<Drawable>() {
                        @Override
                        public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Drawable> target, boolean isFirstResource) {
                            if (isPostDataLoaded) {
                                postImagesLoaded++;
                                if (postImagesLoaded == postImagesCount) {
                                    binding.progressBar.setVisibility(View.GONE);
                                    AlertDialogManager.showAlertDialogMessage(SplashActivity.this, "Error", "Something went wrong, Please try again later", false, "Exit", null, SplashActivity.this, IS_TABLET);
                                }
                            } else {
                                previewImagesLoaded++;
                                if (previewImagesLoaded == previewImagesCount) {
                                    binding.progressBar.setVisibility(View.GONE);
                                    AlertDialogManager.showAlertDialogMessage(SplashActivity.this, "Error", "Something went wrong, Please try again later", false, "Exit", null, SplashActivity.this, IS_TABLET);
                                }
                            }
                            return true;
                        }

                        @Override
                        public boolean onResourceReady(Drawable resource, Object model, Target<Drawable> target, DataSource dataSource, boolean isFirstResource) {
                            if (isPostDataLoaded) {
                                postImagesLoaded++;
                                if (postImagesLoaded == postImagesCount) {
                                    PostSingleton.getInstance().setPostMap(postMap);
                                    startFreshActivity(PreviewActivity.class);
                                }
                            } else {
                                previewImagesLoaded++;
                                if (previewImagesLoaded == previewImagesCount) {
                                    PreviewSingleton.getInstance().setPreviewList(previewList);
                                    getPostImageCount();
                                    postPreloadAllImages();
                                }
                            }
                            return true;
                        }
                    }).preload();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

回答1:

Better to preload all the images with .downloadOnly() instead of using any target. Then load images using FileProvider.

private class CacheImage extends AsyncTask<String,Void,File> {
        @Override
        protected File doInBackground(String... strings) {
            try {
                return Glide.with(getContext())
                        .load(strings[0])
                        .downloadOnly(Target.SIZE_ORIGINAL,Target.SIZE_ORIGINAL)
                        .get();
            } catch (Exception e) {
                Log.e(LOG_TAG,e.getMessage());
                return null;
            }
        }

        @Override
        protected void onPostExecute(File file) {
            if(file!=null){
               Uri file_uri = FileProvider.getUriForFile(getContext(),
                        getContext().getPackageName()+".images",file);
            }
        }
    }

And store the path alongside URL in SQLite. Now get the image_url using FileProvider from SQLite

Glide.with(imageView.getContext())
                .load(<image_url>)
                .asBitmap()
                .dontAnimate()
                .centerCrop()
                .override(<width>,<height>)
                .priority(Priority.IMMEDIATE)
                .diskCacheStrategy(DiskCacheStrategy.SOURCE)
                .skipMemoryCache(true)
                .into(imageView);

You may also need to add,

In manifest, inside <application>

<provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="{app package name}.images"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths" />
    </provider>

Inside res/xml, as file_paths.xml,

<paths xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    <cache-path name="images" path="image_manager_disk_cache"
        tools:path="DiskCache.Factory.DEFAULT_DISK_CACHE_DIR" />
</paths>

来源：https://stackoverflow.com/questions/62624070/how-to-priorly-get-future-glide-image-size-which-will-be-stored-in-cache-in-andr