How to loop large bitmaps smootly in Android

问题

I am creating an Android Application for TV & Tablet devices which shows kind of advertisements in form of images.

I'm using following method to load Bitmaps which I had stored in cache using Universal-image-loader library:

public static Bitmap getSampledBitmapFromFile(File file, int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(file.getPath(), options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeFile(file.getPath(), options);
}

This is how loading Bitmap:

for(int i ==0; i<media.size() ; i++){
new AsyncTask<String, Void, Bitmap>() {
        private final WeakReference<ImageView> imageViewReference =  new WeakReference<ImageView>(campaignImg);
        // Decode image in background.
        @Override
        protected Bitmap doInBackground(String... params) {
            return Config.getSampledBitmapFromFile(ImageLoader.getInstance().getDiskCache().get(params[0]),
                    mDisplayMetrics.widthPixels, mDisplayMetrics.heightPixels);
        }
        // Once complete, see if ImageView is still around and set bitmap.
        @Override
        protected void onPostExecute(Bitmap bitmap) {
            if (bitmap != null) {
                final ImageView imageView = imageViewReference.get();
                if (imageView != null) {
                    imageView.setImageBitmap(bitmap);
                    animateImages(imageView, media.interval);
                }
            }
        }
    }.execute(media.imageUrl);
 }

My problem is app image rotation isn't smooth and images flickering while change. Image is getting changed in 10 second. Following what my logcat says:

 D/dalvikvm: GC_FOR_ALLOC freed 11788K, 66% free 12375K/36295K, paused 19ms, total 19ms
 I/dalvikvm-heap: Grow heap (frag case) to 23.587MB for 12000016-byte allocation
 D/dalvikvm: GC_CONCURRENT freed 2K, 34% free 24091K/36295K, paused 12ms+5ms, total 43ms
 D/dalvikvm: WAIT_FOR_CONCURRENT_GC blocked 17ms
 D/dalvikvm: GC_FOR_ALLOC freed 5923K, 50% free 18241K/36295K, paused 59ms, total 60ms
 I/dalvikvm-heap: Grow heap (frag case) to 29.316MB for 12000016-byte allocation
 D/dalvikvm: GC_CONCURRENT freed 2K, 18% free 29957K/36295K, paused 13ms+6ms, total 50ms
 D/dalvikvm: WAIT_FOR_CONCURRENT_GC blocked 32ms
 D/dalvikvm: GC_FOR_ALLOC freed 11791K, 50% free 18241K/36295K, paused 22ms, total 22ms
 I/dalvikvm-heap: Grow heap (frag case) to 29.316MB for 12000016-byte allocation
 GC_FOR_ALLOC freed 2K, 18% free 29957K/36295K, paused 29ms, total 29ms

What else I can do to reduce memory usages or improve performance?

回答1:

Rai's answer inspried me to use UIL for loading image from the cache. I think I should have done this earlier.

As a learning from this, its always a good idea to use any library for image loading,caching or display instead of manually handling it. As I was already using UIL in my project, I ended up using following:

ImageLoader.getInstance().displayImage(media.imageUrl, campaignImg, new SimpleImageLoadingListener() {
        @Override
        public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
            super.onLoadingComplete(imageUri, view, loadedImage);
            animateImages(campaignImg, media.interval);
        }
    });

回答2:

Use Picasso or Glide libraries to avoid out of memory issues.

Replace path with local folder path or server url

Glide.with (context).load (path).asBitmap().into(imageView);

来源：https://stackoverflow.com/questions/36861868/how-to-loop-large-bitmaps-smootly-in-android

标签

android

memory-management

bitmap

universal-image-loader