Added a UI for the Interests Prototype.

chrome/android/java/src/org/chromium/chrome/browser/ntp/InterestsItemView.java

+// Copyright 2015 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.ntp;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Color;
+import android.graphics.Rect;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+import android.media.ThumbnailUtils;
+import android.os.AsyncTask;
+import android.support.v4.graphics.drawable.RoundedBitmapDrawable;
+import android.support.v4.graphics.drawable.RoundedBitmapDrawableFactory;
+import android.support.v7.widget.AppCompatTextView;
+import android.text.TextUtils;
+import android.util.LruCache;
+import android.util.TypedValue;
+import android.view.Gravity;
+import android.view.View;
+import android.view.View.OnClickListener;
+
+import org.chromium.base.Log;
+import org.chromium.base.ObserverList;
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.ntp.InterestsPage.InterestsClickListener;
+import org.chromium.chrome.browser.ntp.InterestsService.Interest;
+import org.chromium.chrome.browser.widget.RoundedIconGenerator;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+
+/**
+ * Displays the interest name along with an image of it. This item can be clicked.
+ */
+class InterestsItemView extends AppCompatTextView implements OnClickListener {
+
+    private static final String TAG = "InterestsItemView";
+
+    // Color codes to provide a variety of background colours for the letter tiles.
+    // TODO(peconn): Move this, along with getTileColor into a separate class.
+    private static final String[] COLOR_CODES = {"#f16364", "#f58559", "#f9a43e", "#e4c62e",

[newt (away), 2015/12/14 21:18:39]

Just use an int array:

    private static final int[] COLORS = {0xfff16364, ... };

and you can skip the call to Color.parseColor() down below

[PEConn, 2015/12/15 11:50:15]

Done.

+            "#67bf74", "#59a2be", "#2093cd", "#ad62a7"};
+
+    /**
+     * Drawing-related values that can be shared between instances of InterestsItemView.
+     */
+    static final class DrawingData {
+
+        private final int mPadding;
+        private final int mMinHeight;
+        private final int mImageSize;
+        private final int mTextSize;
+        private final int mImageTextSize;
+
+        private final RoundedIconGenerator mIconGenerator;
+
+        /**
+         * Initialize shared values used for drawing the image.
+         *
+         * @param context The view context in which the InterestsItemView will be drawn.
+         */
+        DrawingData(Context context) {
+            Resources res = context.getResources();
+            mPadding = res.getDimensionPixelOffset(R.dimen.ntp_list_item_padding);
+            mMinHeight = res.getDimensionPixelSize(R.dimen.ntp_interest_item_min_height);
+            mTextSize = res.getDimensionPixelSize(R.dimen.ntp_interest_item_text_size);
+            mImageSize = res.getDimensionPixelSize(R.dimen.ntp_interest_item_image_size);
+            mImageTextSize = res.getDimensionPixelSize(R.dimen.ntp_interest_item_image_text_size);
+            mIconGenerator = new RoundedIconGenerator(
+                mImageSize, mImageSize, mImageSize / 2, Color.GRAY, mImageTextSize);
+        }
+    }
+
+    private Interest mInterest;
+
+    private final Context mContext;
+    private final DrawingData mDrawingData;
+    private final LruCache<String, ImageHolder> mImageCache;
+    private final InterestsClickListener mListener;
+
+    /**
+     * @param context The view context in which this item will be shown.
+     * @param interest The interest to display.
+     * @param listener Callback object for when a view is pressed.
+     * @param imageCache A cache to store downloaded images.
+     * @param drawingData Information about the view size.
+     */
+    InterestsItemView(Context context, Interest interest, InterestsClickListener listener,
+            LruCache<String, ImageHolder> imageCache, DrawingData drawingData) {
+        super(context);
+
+        mContext = context;
+        mListener = listener;
+        mImageCache = imageCache;
+        mDrawingData = drawingData;
+
+        setTextSize(TypedValue.COMPLEX_UNIT_PX, mDrawingData.mTextSize);
+        setMinimumHeight(mDrawingData.mMinHeight);
+        setGravity(Gravity.CENTER);
+        setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
+
+        setOnClickListener(this);
+
+        reset(interest);
+    }
+
+    /**
+     * Resets the view contents so that it can be reused in the grid view.
+     *
+     * @param interest The interest to display.
+     */
+    public void reset(Interest interest) {
+        // Reset Drawable state so ripples don't continue when the View is reused.
+        jumpDrawablesToCurrentState();
+
+        // Exit early if this View is already displaying the Interest given.
+        if (mInterest != null
+                && TextUtils.equals(interest.getName(), mInterest.getName())
+                && TextUtils.equals(interest.getImageUrl(), mInterest.getImageUrl())) {
+            mInterest = interest;
+            return;
+        }
+
+        mInterest = interest;
+
+        setText(mInterest.getName());
+
+        ImageHolder placeholder = mImageCache.get(mInterest.getImageUrl());

[newt (away), 2015/12/14 21:18:39]

s/placeholder/holder/

[PEConn, 2015/12/15 11:50:15]

Done.

+        if (placeholder == null) {
+            // Create a new placeholder, add it to the cache and set it downloading.
+            placeholder = new ImageHolder();
+            mImageCache.put(mInterest.getImageUrl(), placeholder);
+            new ImageDownloadTask(mInterest.getImageUrl(), placeholder, getResources()).execute();
+        }
+
+        if (placeholder.getImageDrawable() != null) {
+            setImage(placeholder.getImageDrawable());
+        } else {
+            // Add a callback to a subclass that will call setImage once the placeholder is filled.
+            placeholder.addListener(new ImageDownloadedCallback());
+
+            // Display a letter tile in the meantime.
+            mDrawingData.mIconGenerator.setBackgroundColor(getTileColor(mInterest.getName()));
+            setImage(new BitmapDrawable(mContext.getResources(),
+                    mDrawingData.mIconGenerator.generateIconForText(mInterest.getName())));
+        }
+    }
+
+    /**
+     * @return The image URL for the interest.
+     */
+    public String getImageUrl() {
+        return mInterest.getImageUrl();
+    }
+
+    /**
+     * @return The name of the interest.
+     */
+    public String getName() {
+        return mInterest.getName();
+    }
+
+    private void setImage(Drawable image) {
+        image.setBounds(new Rect(0, 0, mDrawingData.mImageSize, mDrawingData.mImageSize));
+        setCompoundDrawables(null, image, null, null);
+    }
+
+    private int getTileColor(String str) {
+        // Rough copy of LetterTileDrawable.pickColor.
+        // TODO(peconn): Move this to a more general class.
+        return Color.parseColor(COLOR_CODES[Math.abs(str.hashCode() % COLOR_CODES.length)]);
+    }
+
+    @Override
+    public void onClick(View v) {
+        mListener.onInterestClicked(getName());
+    }
+
+    /*
+     * An AsyncTask that downloads an image, formats it then puts it in the given placeholder.
+     */
+    private static class ImageDownloadTask extends AsyncTask<Void, Void, Drawable> {
+
+        private final String mUrl;
+        private final ImageHolder mImagePlaceholder;

[newt (away), 2015/12/14 21:18:39]

s/Placeholder/Holder/

[PEConn, 2015/12/15 11:50:15]

Done.

+        private final Resources mResources;
+
+        public ImageDownloadTask(String url, ImageHolder placeholder, Resources resources) {

[newt (away), 2015/12/14 21:18:39]

s/placeholder/holder/

[PEConn, 2015/12/15 11:50:15]

Done.

+            mUrl = url;
+            mImagePlaceholder = placeholder;
+            mResources = resources;
+        }
+
+        @Override
+        protected Drawable doInBackground(Void... voids) {
+            // This is run on a background thread.
+            try {
+                // TODO(peconn): Replace this with something from the C++ Chrome stack.
+                URL imageUrl = new URL(mUrl);
+                InputStream in = imageUrl.openStream();
+
+                Bitmap raw = BitmapFactory.decodeStream(in);
+                int dimension = Math.min(raw.getHeight(), raw.getWidth());
+                RoundedBitmapDrawable img = RoundedBitmapDrawableFactory.create(mResources,
+                        ThumbnailUtils.extractThumbnail(raw, dimension, dimension));
+                img.setCircular(true);
+
+                return img;
+            } catch (IOException e) {
+                Log.e(TAG, "Error downloading image: " + e.toString());
+            }
+            return null;
+        }
+
+        @Override
+        protected void onPostExecute(Drawable image) {
+            // This is run on the main thread.
+            mImagePlaceholder.set(image, mUrl);
+        }
+    }
+
+    /*
+     * A callback class that will set it's parent's image.
+     */
+    private class ImageDownloadedCallback {
+        public void onImageDownloaded(Drawable image, String url) {
+            if (image == null) {
+                return;
+            }
+            // If the Interest this View is displaying has changed while downloading, do not update
+            // the image.
+            if (url == mInterest.getImageUrl()) {
+                setImage(image);
+            }
+        }
+    }
+
+    /*
+     * A placeholder for an Image that allows listeners to subscribe to when it is set. It is
+     * like a listenable future that doesn't calculate the value itself. It can only be
+     * accessed on one thread. It can only be set once.
+     */
+    static class ImageHolder {
+        private final ObserverList<ImageDownloadedCallback> mCallbacks = new ObserverList<>();
+        private Drawable mImage;
+        private String mUrl;
+
+        public void set(Drawable image, String url) {
+            assert mImage == null;
+            mImage = image;
+            mUrl = url;
+
+            for (ImageDownloadedCallback callbacks : mCallbacks) {
+                callbacks.onImageDownloaded(image, mUrl);
+            }
+
+            mCallbacks.clear();
+        }
+
+        public void addListener(ImageDownloadedCallback callback) {
+            if (mImage == null) {
+                mCallbacks.addObserver(callback);
+            } else {
+                callback.onImageDownloaded(mImage, mUrl);
+            }
+        }
+
+        public Drawable getImageDrawable() {
+            return mImage;
+        }
+    }
+}