Photo Picker Dialog: Recursively traverse the photo directories.

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java

Index: chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java
index b4151f27bcb592e6ddb8005a09d1304d1274742d..4098480e532b3c34513c5690f6230635df2e33b6 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java
@@ -21,14 +21,14 @@ import org.chromium.chrome.browser.widget.selection.SelectableListLayout;
 import org.chromium.chrome.browser.widget.selection.SelectionDelegate;
 import org.chromium.ui.PhotoPickerListener;
 
-import java.util.ArrayList;
 import java.util.List;
 
 /**
  * A class for keeping track of common data associated with showing photos in
  * the photo picker, for example the RecyclerView and the bitmap caches.
  */
-public class PickerCategoryView extends RelativeLayout implements OnMenuItemClickListener {
+public class PickerCategoryView extends RelativeLayout
+        implements FileEnumWorkerTask.FilesEnumeratedCallback, OnMenuItemClickListener {
     // The dialog that owns us.
     private PhotoPickerDialog mDialog;
 
@@ -69,6 +69,9 @@ public class PickerCategoryView extends RelativeLayout implements OnMenuItemClic
     // The size of the bitmaps (equal length for width and height).
     private int mImageSize;
 
+    // A worker task for asynchronously enumerating files off the main thread.
+    private FileEnumWorkerTask mWorkerTask;
+
     public PickerCategoryView(Context context) {
         super(context);
         postConstruction(context);
@@ -119,6 +122,13 @@ public class PickerCategoryView extends RelativeLayout implements OnMenuItemClic
     }
 
     /**
+     * Cancels any outstanding requests.
+     */
+    public void teardown() {

[Theresa, 2017/04/11 17:01:29]

nit: I think teardown() is typically used in test classes but not regular
classes. This could be something like onDialogDismissed() or destroy().


super nit: We check if mWorkerTask != null in prepareBitmaps(), which shouldn't
be possible since we only end up calling that method through the constructor.
But we don't check if mWorkerTask != null here.  Maybe we should also check here
that mWorkerTask != null, and set mWorkTask = null when the callback is
received?

[Finnur, 2017/04/12 11:04:43]

Done.
It isn't possible now, but that's only because this is a trimmed CL with sync
loading of images. In a future CL, this can be null.
Added null-check.

+        mWorkerTask.cancel(true);
+    }
+
+    /**
      * Initializes the PickerCategoryView object.
      * @param dialog The dialog showing us.
      * @param listener The listener who should be notified of actions.
@@ -133,6 +143,16 @@ public class PickerCategoryView extends RelativeLayout implements OnMenuItemClic
         mListener = listener;
     }
 
+    // FileEnumWorkerTask.FilesEnumeratedCallback:
+
+    @Override
+    public void filesEnumeratedCallback(List<PickerBitmap> files) {
+        mPickerBitmaps = files;
+        if (files != null && files.size() > 0) {
+            mPickerAdapter.notifyDataSetChanged();
+        }
+    }
+
     // OnMenuItemClickListener:
 
     @Override
@@ -202,15 +222,12 @@ public class PickerCategoryView extends RelativeLayout implements OnMenuItemClic
      * Prepares bitmaps for loading.
      */
     private void prepareBitmaps() {
-        // TODO(finnur): Use worker thread to fetch bitmaps instead of hard-coding.
-        mPickerBitmaps = new ArrayList<>();
-        mPickerBitmaps.add(0, new PickerBitmap("", 0, PickerBitmap.GALLERY));
-        mPickerBitmaps.add(0, new PickerBitmap("", 0, PickerBitmap.CAMERA));
-        mPickerBitmaps.add(new PickerBitmap("foo/bar1.jpg", 1, PickerBitmap.PICTURE));
-        mPickerBitmaps.add(new PickerBitmap("foo/bar2.jpg", 2, PickerBitmap.PICTURE));
-        mPickerBitmaps.add(new PickerBitmap("foo/bar3.jpg", 3, PickerBitmap.PICTURE));
-        mPickerBitmaps.add(new PickerBitmap("foo/bar4.jpg", 4, PickerBitmap.PICTURE));
-        mPickerAdapter.notifyDataSetChanged();
+        if (mWorkerTask != null) {
+            mWorkerTask.cancel(true);
+        }
+
+        mWorkerTask = new FileEnumWorkerTask(this, new MimeTypeFileFilter("image/*"));
+        mWorkerTask.execute();
     }
 
     /**