Add backgrounds.

Change-Id: I1f48ab3f6b914132f0c2560657e419b3f3ace882

samples/SupportLeanbackDemos/src/com/example/android/leanback/BackgroundHelper.java

@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.example.android.leanback;
+
+import android.app.Activity;
+import android.graphics.Bitmap;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+import android.os.AsyncTask;
+import android.os.Handler;
+import android.support.v17.leanback.app.BackgroundManager;
+import android.util.Log;
+
+public class BackgroundHelper {
+
+    private static final String TAG = "BackgroundHelper";
+    private static final boolean DEBUG = false;
+    private static final boolean ENABLED = true;
+
+    // Background delay serves to avoid kicking off expensive bitmap loading
+    // in case multiple backgrounds are set in quick succession.
+    private static final int SET_BACKGROUND_DELAY_MS = 100;
+
+    static class Request {
+        Object mImageToken;
+        Activity mActivity;
+        Bitmap mResult;
+
+        Request(Activity activity, Object imageToken) {
+            mActivity = activity;
+            mImageToken = imageToken;
+        }
+    }
+
+    public BackgroundHelper() {
+        if (DEBUG && !ENABLED) Log.v(TAG, "BackgroundHelper: disabled");
+    }
+
+    class LoadBackgroundRunnable implements Runnable {
+        Request mRequest;
+
+        LoadBackgroundRunnable(Activity activity, Object imageToken) {
+            mRequest = new Request(activity, imageToken);
+        }
+
+        @Override
+        public void run() {
+            if (mTask != null) {
+                if (DEBUG) Log.v(TAG, "Cancelling task");
+                mTask.cancel(true);
+            }
+            if (DEBUG) Log.v(TAG, "Executing task");
+            mTask = new LoadBitmapTask();
+            mTask.execute(mRequest);
+            mRunnable = null;
+        }
+    };
+
+    class LoadBitmapTask extends AsyncTask<Request, Object, Request> {
+        @Override
+        protected Request doInBackground(Request... params) {
+            boolean cancelled = isCancelled();
+            if (DEBUG) Log.v(TAG, "doInBackground cancelled " + cancelled);
+            Request request = params[0];
+            if (!cancelled) {
+                request.mResult = loadBitmap(request.mActivity, request.mImageToken);
+            }
+            return request;
+        }
+
+        @Override
+        protected void onPostExecute(Request request) {
+            if (DEBUG) Log.v(TAG, "onPostExecute");
+            applyBackground(request.mActivity, request.mResult);
+            if (mTask == this) {
+                mTask = null;
+            }
+        }
+
+        @Override
+        protected void onCancelled(Request request) {
+            if (DEBUG) Log.v(TAG, "onCancelled");
+        }
+
+        private Bitmap loadBitmap(Activity activity, Object imageToken) {
+            if (imageToken instanceof Integer) {
+                final int resourceId = (Integer) imageToken;
+                Drawable drawable = activity.getDrawable(resourceId);
+                if (drawable instanceof BitmapDrawable) {
+                    return ((BitmapDrawable) drawable).getBitmap();
+                }
+            }
+            return null;
+        }
+
+        private void applyBackground(Activity activity, Bitmap bitmap) {
+            BackgroundManager backgroundManager = BackgroundManager.getInstance(activity);
+            if (bitmap == null || backgroundManager == null || !backgroundManager.isAttached()) {
+                return;
+            }
+            backgroundManager.setBitmap(bitmap);
+        }
+    }
+
+    private LoadBackgroundRunnable mRunnable;
+    private LoadBitmapTask mTask;
+
+    public void attach(Activity activity) {
+        if (!ENABLED) {
+            return;
+        }
+        BackgroundManager.getInstance(activity).attach(activity.getWindow());
+    }
+
+    public void setBackground(Activity activity, Object imageToken) {
+        if (!ENABLED) {
+            return;
+        }
+        Handler handler = activity.getWindow().getDecorView().getHandler();
+        if (mRunnable != null) {
+            handler.removeCallbacks(mRunnable);
+        }
+        mRunnable = new LoadBackgroundRunnable(activity, imageToken);
+        handler.postDelayed(mRunnable, SET_BACKGROUND_DELAY_MS);
+    }
+}

samples/SupportLeanbackDemos/src/com/example/android/leanback/BrowseFragment.java

@@ -37,6 +37,7 @@ public class BrowseFragment extends android.support.v17.leanback.app.BrowseFragm
     private static final boolean TEST_ENTRANCE_TRANSITION = true;
     private static final int NUM_ROWS = 10;
     private ArrayObjectAdapter mRowsAdapter;
+    private BackgroundHelper mBackgroundHelper = new BackgroundHelper();
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
@@ -62,6 +63,11 @@ public class BrowseFragment extends android.support.v17.leanback.app.BrowseFragm
             public void onItemSelected(Presenter.ViewHolder itemViewHolder, Object item,
                     RowPresenter.ViewHolder rowViewHolder, Row row) {
                 Log.i(TAG, "onItemSelected: " + item + " row " + row);
+
+                if (item instanceof PhotoItem) {
+                    mBackgroundHelper.setBackground(
+                            getActivity(), ((PhotoItem) item).getImageResourceId());
+                }
             }
         });
         if (TEST_ENTRANCE_TRANSITION) {
@@ -76,6 +82,8 @@ public class BrowseFragment extends android.support.v17.leanback.app.BrowseFragm
                 }
             }, 2000);
         }
+
+        mBackgroundHelper.attach(getActivity());
     }
 
     private void setupRows() {

samples/SupportLeanbackDemos/src/com/example/android/leanback/DetailsFragment.java

@@ -44,6 +44,7 @@ public class DetailsFragment extends android.support.v17.leanback.app.DetailsFra
     private ArrayObjectAdapter mRowsAdapter;
     private PhotoItem mPhotoItem;
     final CardPresenter cardPresenter = new CardPresenter();
+    private BackgroundHelper mBackgroundHelper = new BackgroundHelper();
 
     private static final int ACTION_BUY = 1;
     private static final int ACTION_RENT = 2;
@@ -131,6 +132,8 @@ public class DetailsFragment extends android.support.v17.leanback.app.DetailsFra
                 prepareEntranceTransition();
             }
         }
+
+        mBackgroundHelper.attach(getActivity());
     }
 
     @Override