Implement the new Photo picker, part two.

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

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.photo_picker;
+
+import android.app.Activity;
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffColorFilter;
+import android.support.v7.widget.GridLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.Toolbar.OnMenuItemClickListener;
+import android.util.AttributeSet;
+import android.view.LayoutInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.widget.RelativeLayout;
+
+import org.chromium.chrome.R;
+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 {
+    private static final int KILOBYTE = 1024;
+
+    // The dialog that owns us.
+    private PhotoPickerDialog mDialog;
+
+    // The view containing the recycler view and the toolbar, etc.
+    private SelectableListLayout<PickerBitmap> mSelectableListLayout;
+
+    // Our context.
+    private Context mContext;
+
+    // The list of images on disk, sorted by last-modified first.
+    private List<PickerBitmap> mPickerBitmaps;
+
+    // True if multi-selection is allowed in the picker.
+    private boolean mMultiSelectionAllowed;
+
+    // The callback to notify the listener of decisions reached in the picker.
+    private PhotoPickerListener mListener;
+
+    // The recycler view showing the images.
+    private RecyclerView mRecyclerView;
+
+    // The picker adapter for the RecyclerView.
+    private PickerAdapter mPickerAdapter;
+
+    // The selection delegate keeping track of which images are selected.
+    private SelectionDelegate<PickerBitmap> mSelectionDelegate;
+
+    /**
+     * The number of columns to show. Note: mColumns and mPadding (see below) should both be even
+     * numbers or both odd, not a mix (the column padding will not be of uniform thickness if they
+     * are a mix).
+     */
+    private int mColumns;
+
+    // The padding between columns. See also comment for mColumns.
+    private int mPadding;
+
+    // The size of the bitmaps (equal length for width and height).
+    private int mImageSize;
+
+    public PickerCategoryView(Context context) {
+        super(context);
+        init(context);
+    }
+
+    public PickerCategoryView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        init(context);
+    }
+
+    public PickerCategoryView(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        init(context);
+    }
+
+    /**
+     * A helper function for initializing the PickerCategoryView.
+     * @param context The context to use.
+     */
+    @SuppressWarnings("unchecked") // mSelectableListLayout
+    private void init(Context context) {
+        mContext = context;
+
+        mSelectionDelegate = new SelectionDelegate<PickerBitmap>();
+
+        View root = LayoutInflater.from(context).inflate(R.layout.photo_picker_dialog, this);
+        mSelectableListLayout =
+                (SelectableListLayout<PickerBitmap>) root.findViewById(R.id.selectable_list);
+
+        mPickerAdapter = new PickerAdapter(this);
+        mRecyclerView = mSelectableListLayout.initializeRecyclerView(mPickerAdapter);
+        mSelectableListLayout.initializeToolbar(R.layout.photo_picker_toolbar, mSelectionDelegate,
+                R.string.menu_history, null, R.id.file_picker_normal_menu_group,
+                R.id.file_picker_selection_mode_menu_group, R.color.default_primary_color, false,
+                this);
+
+        View view = ((Activity) context).getWindow().getDecorView();

[Theresa, 2017/03/31 18:05:56]

getDecorView() contains all of the window decoration (e.g. Android status bar,
bottom controls). Is that desired?

[Finnur, 2017/04/03 17:30:30]

We only care about the width here.

[Theresa, 2017/04/04 15:48:32]

Sometimes the width contains the window decorations e.g. a Nexus 6P in
landscape.

If you only want the app's dimensions, use:
Rect appRect = new Rect();   
mActivity.getWindow().getDecorView().getWindowVisibleDisplayFrame(appRect);

[Finnur, 2017/04/04 18:05:36]

Done.

+        int width = view.getWidth() - view.getPaddingLeft() - view.getPaddingRight();
+
+        calculateGridMetrics(width);
+
+        RecyclerView.LayoutManager mLayoutManager = new GridLayoutManager(mContext, mColumns);
+        mRecyclerView.setHasFixedSize(true);
+        mRecyclerView.setLayoutManager(mLayoutManager);
+        // TODO(finnur): Implement grid spacing.
+        // TODO(finnur): Implement caching.
+        // TODO(finnur): Remove this once the decoder service is in place.
+        prepareBitmaps();
+    }
+
+    /**
+     * Sets the starting state for the PickerCategoryView object.
+     * @param dialog The dialog showing us.
+     * @param listener The listener who should be notified of actions.
+     * @param multiSelection Whether to allow the user to select more than one image.
+     */
+    public void setStartingState(

[Theresa, 2017/03/31 18:05:56]

The values set in this don't appear to change so #setStartinState() doesn't seem
like an appropriate method name. Typically I'd recommend #initialize() but
there's already an #init() method...

[Finnur, 2017/04/03 17:30:30]

Yeah, I struggled with this as well. All I can think of is setup()... I don't
know. Is that better?

[Theresa, 2017/04/04 15:48:32]

What about something like postConstruction() for the other method and
initialize() (or init()) for this method?

[Finnur, 2017/04/04 18:05:36]

Sounds reasonable.

+            PhotoPickerDialog dialog, PhotoPickerListener listener, boolean multiSelection) {

[Theresa, 2017/03/31 18:05:56]

Please rename this parameter to match mMultiSelectionAllowed.

[Finnur, 2017/04/03 17:30:30]

Done.

+        // TODO(finnur): Change selection delegate to support single-selection.
+
+        mDialog = dialog;
+        mMultiSelectionAllowed = multiSelection;
+        mListener = listener;
+    }
+
+    // OnMenuItemClickListener:
+
+    @Override
+    public boolean onMenuItemClick(MenuItem item) {
+        if (item.getItemId() == R.id.close_menu_id
+                || item.getItemId() == R.id.selection_mode_done_menu_id) {
+            tryNotifyPhotoSet();
+            mDialog.dismiss();
+            return true;
+        }
+        return false;
+    }
+
+    // Simple accessors:
+
+    public int getImageSize() {
+        return mImageSize;
+    }
+    public SelectionDelegate<PickerBitmap> getSelectionDelegate() {

[Theresa, 2017/03/31 18:05:56]

nit: add a blank space above this method and the others in this block as well.

[Finnur, 2017/04/03 17:30:30]

Done.

+        return mSelectionDelegate;
+    }
+    public List<PickerBitmap> getPickerBitmaps() {
+        return mPickerBitmaps;
+    }
+    public boolean isMultiSelect() {

[Theresa, 2017/03/31 18:05:56]

Please rename this method as well.

[Finnur, 2017/04/03 17:30:30]

Done.

+        return mMultiSelectionAllowed;
+    }
+
+    /**
+     * Notifies the caller that the user selected to launch the gallery.
+     */
+    public void showGallery() {
+        mListener.onPickerUserAction(PhotoPickerListener.Action.LAUNCH_GALLERY, null);
+    }
+
+    /**
+     * Notifies the caller that the user selected to launch the camera intent.
+     */
+    public void showCamera() {
+        mListener.onPickerUserAction(PhotoPickerListener.Action.LAUNCH_CAMERA, null);
+    }
+
+    /**
+     * Applies a color filter to a bitmap.
+     * @param original The bitmap to color.
+     * @param color The color to apply.
+     * @return A colored bitmap.
+     */
+    private Bitmap colorBitmap(Bitmap original, int color) {

[Theresa, 2017/03/31 18:05:56]

It looks like this is no longer used.

[Finnur, 2017/04/03 17:30:30]

Correct.

+        Bitmap mutable = original.copy(Bitmap.Config.ARGB_8888, true);
+        Canvas canvas = new Canvas(mutable);
+        Paint paint = new Paint();
+        paint.setColorFilter(new PorterDuffColorFilter(color, PorterDuff.Mode.SRC_IN));
+        canvas.drawBitmap(mutable, 0.f, 0.f, paint);
+        return mutable;
+    }
+
+    /**
+     * Calculates image size and how many columns can fit on-screen.
+     * @param width The total width of the boundary to show the images in.
+     */
+    private void calculateGridMetrics(int width) {
+        int minSize =
+                mContext.getResources().getDimensionPixelSize(R.dimen.file_picker_tile_min_size);
+        mPadding = mContext.getResources().getDimensionPixelSize(R.dimen.file_picker_tile_gap);
+        mColumns = Math.max(1, (width - mPadding) / (minSize + mPadding));
+        mImageSize = (width - mPadding * (mColumns + 1)) / (mColumns);
+
+        // Make sure columns and padding are either both even or both odd.
+        if (((mColumns % 2) == 0) != ((mPadding % 2) == 0)) {
+            mPadding++;
+        }
+    }
+
+    /**
+     * 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.TileTypes.GALLERY));
+        mPickerBitmaps.add(0, new PickerBitmap("", 0, PickerBitmap.TileTypes.CAMERA));
+        mPickerBitmaps.add(new PickerBitmap("foo/bar1.jpg", 1, PickerBitmap.TileTypes.PICTURE));
+        mPickerBitmaps.add(new PickerBitmap("foo/bar2.jpg", 2, PickerBitmap.TileTypes.PICTURE));
+        mPickerBitmaps.add(new PickerBitmap("foo/bar3.jpg", 3, PickerBitmap.TileTypes.PICTURE));
+        mPickerBitmaps.add(new PickerBitmap("foo/bar4.jpg", 4, PickerBitmap.TileTypes.PICTURE));
+        mPickerAdapter.notifyDataSetChanged();
+    }
+
+    /**
+     * Tries to notify any listeners that one or more photos have been selected.

[Theresa, 2017/03/31 18:05:56]

When would it not successfully notify the listener? I'm thinking this can just
be notfiyPhotosSelected()

[Finnur, 2017/04/03 17:30:30]

Yes, in an old revision this could actually result in no notification, but
that's no longer the case, as you point out.

+     */
+    private void tryNotifyPhotoSet() {
+        List<PickerBitmap> selectedFiles = mSelectionDelegate.getSelectedItems();
+        String[] photos = new String[selectedFiles.size()];
+        int i = 0;
+        for (PickerBitmap bitmap : selectedFiles) {
+            photos[i++] = bitmap.getFilePath();
+        }
+
+        mListener.onPickerUserAction(PhotoPickerListener.Action.PHOTOS_SELECTED, photos);
+    }
+}