- set priority of image processing to higher value

- cancel all pending async tasks when leaving FDA: needs to be done by get.abort() as this is a blocking command and needs to be accessed directly

src/main/java/com/owncloud/android/datamodel/ThumbnailsCacheManager.java

@@ -56,6 +56,7 @@ import org.apache.commons.httpclient.methods.GetMethod;
 import java.io.File;
 import java.io.InputStream;
 import java.lang.ref.WeakReference;
+import java.util.ArrayList;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
@@ -183,13 +184,20 @@ public class ThumbnailsCacheManager {
     public static class ThumbnailGenerationTask extends AsyncTask<Object, Void, Bitmap> {
         private final WeakReference<ImageView> mImageViewReference;
         private static Account mAccount;
+        private ArrayList<ThumbnailGenerationTask> mAsyncTasks = null;
         private Object mFile;
         private String mImageKey = null;
         private FileDataStorageManager mStorageManager;
+        private GetMethod getMethod;
 
+        public ThumbnailGenerationTask(ImageView imageView, FileDataStorageManager storageManager, Account account)
+                throws IllegalArgumentException {
+            this(imageView, storageManager, account, null);
+        }
 
         public ThumbnailGenerationTask(ImageView imageView, FileDataStorageManager storageManager,
-                                       Account account) throws IllegalArgumentException {
+                                       Account account, ArrayList<ThumbnailGenerationTask> asyncTasks)
+                throws IllegalArgumentException {
             // Use a WeakReference to ensure the ImageView can be garbage collected
             mImageViewReference = new WeakReference<ImageView>(imageView);
             if (storageManager == null) {
@@ -197,6 +205,11 @@ public class ThumbnailsCacheManager {
             }
             mStorageManager = storageManager;
             mAccount = account;
+            mAsyncTasks = asyncTasks;
+        }
+
+        public GetMethod getGetMethod() {
+            return getMethod;
         }
 
         public ThumbnailGenerationTask(FileDataStorageManager storageManager, Account account){
@@ -277,6 +290,10 @@ public class ThumbnailsCacheManager {
                     }
                 }
             }
+
+            if (mAsyncTasks != null) {
+                mAsyncTasks.remove(this);
+            }
         }
 
         /**
@@ -325,18 +342,18 @@ public class ThumbnailsCacheManager {
                     OwnCloudVersion serverOCVersion = AccountUtils.getServerVersion(mAccount);
                     if (mClient != null && serverOCVersion != null) {
                         if (serverOCVersion.supportsRemoteThumbnails()) {
-                            GetMethod get = null;
+                            getMethod = null;
                             try {
                                 String uri = mClient.getBaseUri() + "" +
                                         "/index.php/apps/files/api/v1/thumbnail/" +
                                         px + "/" + px + Uri.encode(file.getRemotePath(), "/");
                                 Log_OC.d("Thumbnail", "URI: " + uri);
-                                get = new GetMethod(uri);
-                                get.setRequestHeader("Cookie",
+                                getMethod = new GetMethod(uri);
+                                getMethod.setRequestHeader("Cookie",
                                         "nc_sameSiteCookielax=true;nc_sameSiteCookiestrict=true");
-                                int status = mClient.executeMethod(get);
+                                int status = mClient.executeMethod(getMethod);
                                 if (status == HttpStatus.SC_OK) {
-                                    InputStream inputStream = get.getResponseBodyAsStream();
+                                    InputStream inputStream = getMethod.getResponseBodyAsStream();
                                     Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                                     thumbnail = ThumbnailUtils.extractThumbnail(bitmap, px, px);
 
@@ -350,13 +367,13 @@ public class ThumbnailsCacheManager {
                                         addBitmapToCache(imageKey, thumbnail);
                                     }
                                 } else {
-                                    mClient.exhaustResponse(get.getResponseBodyAsStream());
+                                    mClient.exhaustResponse(getMethod.getResponseBodyAsStream());
                                 }
                             } catch (Exception e) {
                                 Log_OC.d(TAG, e.getMessage(), e);
                             } finally {
-                                if (get != null) {
-                                    get.releaseConnection();
+                                if (getMethod != null) {
+                                    getMethod.releaseConnection();
                                 }
                             }
                         } else {

src/main/java/com/owncloud/android/ui/adapter/FileListListAdapter.java

@@ -92,6 +92,8 @@ public class FileListListAdapter extends BaseAdapter {
     private OCFile currentDirectory;
     private static final String TAG = FileListListAdapter.class.getSimpleName();
 
+    private ArrayList<ThumbnailsCacheManager.ThumbnailGenerationTask> asyncTasks = new ArrayList<>();
+
     public FileListListAdapter(
             boolean justFolders,
             Context context,
@@ -375,8 +377,7 @@ public class FileListListAdapter extends BaseAdapter {
                             try {
                                 final ThumbnailsCacheManager.ThumbnailGenerationTask task =
                                         new ThumbnailsCacheManager.ThumbnailGenerationTask(
-                                                fileIcon, mStorageManager, mAccount
-                                        );
+                                                fileIcon, mStorageManager, mAccount, asyncTasks);
 
                                 if (thumbnail == null) {
                                     if (MimeTypeUtil.isVideo(file)) {
@@ -392,6 +393,7 @@ public class FileListListAdapter extends BaseAdapter {
                                                 task
                                         );
                                 fileIcon.setImageDrawable(asyncDrawable);
+                                asyncTasks.add(task);
                                 task.execute(file);
                             } catch (IllegalArgumentException e) {
                                 Log_OC.d(TAG, "ThumbnailGenerationTask : " + e.getMessage());
@@ -711,4 +713,18 @@ public class FileListListAdapter extends BaseAdapter {
         return ret;
     }
 
+    public void cancelAllPendingTasks() {
+        for (ThumbnailsCacheManager.ThumbnailGenerationTask task : asyncTasks) {
+            if (task != null) {
+                task.cancel(true);
+                if (task.getGetMethod() != null) {
+                    Log_OC.d(TAG, "cancel: abort get method directly");
+                    task.getGetMethod().abort();
+                }
+            }
+        }
+
+        asyncTasks.clear();
+    }
+
 }

src/main/java/com/owncloud/android/ui/fragment/OCFileListFragment.java

@@ -278,6 +278,14 @@ public class OCFileListFragment extends ExtendedListFragment implements OCFileLi
         super.onDetach();
     }
 
+    @Override
+    public void onPause() {
+        super.onPause();
+        mAdapter.cancelAllPendingTasks();
+    }
+
+
+
     /**
      * {@inheritDoc}
      */

src/main/java/com/owncloud/android/ui/preview/PreviewImageFragment.java

@@ -32,6 +32,7 @@ import android.graphics.drawable.PictureDrawable;
 import android.os.AsyncTask;
 import android.os.Build;
 import android.os.Bundle;
+import android.os.Process;
 import android.support.annotation.DrawableRes;
 import android.support.annotation.StringRes;
 import android.support.v4.app.FragmentStatePagerAdapter;
@@ -442,6 +443,9 @@ public class PreviewImageFragment extends FileFragment {
 
         @Override
         protected LoadImage doInBackground(OCFile... params) {
+            Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_BACKGROUND +
+                    android.os.Process.THREAD_PRIORITY_MORE_FAVORABLE);
+
             Bitmap bitmapResult = null;
             Drawable drawableResult = null;