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RemoteViewsAdapter.javaAPI DocAndroid 5.1 API56941Thu Mar 12 22:22:10 GMT 2015android.widget

RemoteViewsAdapter

public class RemoteViewsAdapter extends BaseAdapter implements Handler.Callback
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Fields Summary
private static final String
MULTI_USER_PERM
private static final String
TAG
private static final int
sDefaultCacheSize
private static final int
sUnbindServiceDelay
private static final int
sDefaultLoadingViewHeight
private static final int
sDefaultMessageType
private static final int
sUnbindServiceMessageType
private final android.content.Context
mContext
private final android.content.Intent
mIntent
private final int
mAppWidgetId
private android.view.LayoutInflater
mLayoutInflater
private RemoteViewsAdapterServiceConnection
mServiceConnection
private WeakReference
mCallback
private android.widget.RemoteViews.OnClickHandler
mRemoteViewsOnClickHandler
private FixedSizeRemoteViewsCache
mCache
private int
mVisibleWindowLowerBound
private int
mVisibleWindowUpperBound
private boolean
mNotifyDataSetChangedAfterOnServiceConnected
private RemoteViewsFrameLayoutRefSet
mRequestedViews
private android.os.HandlerThread
mWorkerThread
private android.os.Handler
mWorkerQueue
private android.os.Handler
mMainQueue
private static final HashMap
sCachedRemoteViewsCaches
private static final HashMap
sRemoteViewsCacheRemoveRunnables
private static android.os.HandlerThread
sCacheRemovalThread
private static android.os.Handler
sCacheRemovalQueue
private static final int
REMOTE_VIEWS_CACHE_DURATION
private boolean
mDataReady
Constructors Summary
public RemoteViewsAdapter(android.content.Context context, android.content.Intent intent, RemoteAdapterConnectionCallback callback)

        mContext = context;
        mIntent = intent;

        mAppWidgetId = intent.getIntExtra(RemoteViews.EXTRA_REMOTEADAPTER_APPWIDGET_ID, -1);

        mLayoutInflater = LayoutInflater.from(context);
        if (mIntent == null) {
            throw new IllegalArgumentException("Non-null Intent must be specified.");
        }
        mRequestedViews = new RemoteViewsFrameLayoutRefSet();

        // Strip the previously injected app widget id from service intent
        if (intent.hasExtra(RemoteViews.EXTRA_REMOTEADAPTER_APPWIDGET_ID)) {
            intent.removeExtra(RemoteViews.EXTRA_REMOTEADAPTER_APPWIDGET_ID);
        }

        // Initialize the worker thread
        mWorkerThread = new HandlerThread("RemoteViewsCache-loader");
        mWorkerThread.start();
        mWorkerQueue = new Handler(mWorkerThread.getLooper());
        mMainQueue = new Handler(Looper.myLooper(), this);

        if (sCacheRemovalThread == null) {
            sCacheRemovalThread = new HandlerThread("RemoteViewsAdapter-cachePruner");
            sCacheRemovalThread.start();
            sCacheRemovalQueue = new Handler(sCacheRemovalThread.getLooper());
        }

        // Initialize the cache and the service connection on startup
        mCallback = new WeakReference<RemoteAdapterConnectionCallback>(callback);
        mServiceConnection = new RemoteViewsAdapterServiceConnection(this);

        RemoteViewsCacheKey key = new RemoteViewsCacheKey(new Intent.FilterComparison(mIntent),
                mAppWidgetId);

        synchronized(sCachedRemoteViewsCaches) {
            if (sCachedRemoteViewsCaches.containsKey(key)) {
                mCache = sCachedRemoteViewsCaches.get(key);
                synchronized (mCache.mMetaData) {
                    if (mCache.mMetaData.count > 0) {
                        // As a precautionary measure, we verify that the meta data indicates a
                        // non-zero count before declaring that data is ready.
                        mDataReady = true;
                    }
                }
            } else {
                mCache = new FixedSizeRemoteViewsCache(sDefaultCacheSize);
            }
            if (!mDataReady) {
                requestBindService();
            }
        }
Methods Summary
private voidenqueueDeferredUnbindServiceMessage()

        // Remove any existing deferred-unbind messages
        mMainQueue.removeMessages(sUnbindServiceMessageType);
        mMainQueue.sendEmptyMessageDelayed(sUnbindServiceMessageType, sUnbindServiceDelay);
protected voidfinalize()

        try {
            if (mWorkerThread != null) {
                mWorkerThread.quit();
            }
        } finally {
            super.finalize();
        }
private intgetConvertViewTypeId(android.view.View convertView)
Returns the item type id for the specified convert view. Returns -1 if the convert view is invalid.

        int typeId = -1;
        if (convertView != null) {
            Object tag = convertView.getTag(com.android.internal.R.id.rowTypeId);
            if (tag != null) {
                typeId = (Integer) tag;
            }
        }
        return typeId;
public intgetCount()

        final RemoteViewsMetaData metaData = mCache.getMetaData();
        synchronized (metaData) {
            return metaData.count;
        }
public java.lang.ObjectgetItem(int position)

        // Disallow arbitrary object to be associated with an item for the time being
        return null;
public longgetItemId(int position)

        synchronized (mCache) {
            if (mCache.containsMetaDataAt(position)) {
                return mCache.getMetaDataAt(position).itemId;
            }
            return 0;
        }
public intgetItemViewType(int position)

        int typeId = 0;
        synchronized (mCache) {
            if (mCache.containsMetaDataAt(position)) {
                typeId = mCache.getMetaDataAt(position).typeId;
            } else {
                return 0;
            }
        }

        final RemoteViewsMetaData metaData = mCache.getMetaData();
        synchronized (metaData) {
            return metaData.getMappedViewType(typeId);
        }
public android.content.IntentgetRemoteViewsServiceIntent()

        return mIntent;
public android.view.ViewgetView(int position, android.view.View convertView, android.view.ViewGroup parent)

        // "Request" an index so that we can queue it for loading, initiate subsequent
        // preloading, etc.
        synchronized (mCache) {
            boolean isInCache = mCache.containsRemoteViewAt(position);
            boolean isConnected = mServiceConnection.isConnected();
            boolean hasNewItems = false;

            if (convertView != null && convertView instanceof RemoteViewsFrameLayout) {
                mRequestedViews.removeView((RemoteViewsFrameLayout) convertView);
            }

            if (!isInCache && !isConnected) {
                // Requesting bind service will trigger a super.notifyDataSetChanged(), which will
                // in turn trigger another request to getView()
                requestBindService();
            } else {
                // Queue up other indices to be preloaded based on this position
                hasNewItems = mCache.queuePositionsToBePreloadedFromRequestedPosition(position);
            }

            if (isInCache) {
                View convertViewChild = null;
                int convertViewTypeId = 0;
                RemoteViewsFrameLayout layout = null;

                if (convertView instanceof RemoteViewsFrameLayout) {
                    layout = (RemoteViewsFrameLayout) convertView;
                    convertViewChild = layout.getChildAt(0);
                    convertViewTypeId = getConvertViewTypeId(convertViewChild);
                }

                // Second, we try and retrieve the RemoteViews from the cache, returning a loading
                // view and queueing it to be loaded if it has not already been loaded.
                Context context = parent.getContext();
                RemoteViews rv = mCache.getRemoteViewsAt(position);
                RemoteViewsIndexMetaData indexMetaData = mCache.getMetaDataAt(position);
                int typeId = indexMetaData.typeId;

                try {
                    // Reuse the convert view where possible
                    if (layout != null) {
                        if (convertViewTypeId == typeId) {
                            rv.reapply(context, convertViewChild, mRemoteViewsOnClickHandler);
                            return layout;
                        }
                        layout.removeAllViews();
                    } else {
                        layout = new RemoteViewsFrameLayout(context);
                    }

                    // Otherwise, create a new view to be returned
                    View newView = rv.apply(context, parent, mRemoteViewsOnClickHandler);
                    newView.setTagInternal(com.android.internal.R.id.rowTypeId,
                            new Integer(typeId));
                    layout.addView(newView);
                    return layout;

                } catch (Exception e){
                    // We have to make sure that we successfully inflated the RemoteViews, if not
                    // we return the loading view instead.
                    Log.w(TAG, "Error inflating RemoteViews at position: " + position + ", using" +
                            "loading view instead" + e);

                    RemoteViewsFrameLayout loadingView = null;
                    final RemoteViewsMetaData metaData = mCache.getMetaData();
                    synchronized (metaData) {
                        loadingView = metaData.createLoadingView(position, convertView, parent,
                                mCache, mLayoutInflater, mRemoteViewsOnClickHandler);
                    }
                    return loadingView;
                } finally {
                    if (hasNewItems) loadNextIndexInBackground();
                }
            } else {
                // If the cache does not have the RemoteViews at this position, then create a
                // loading view and queue the actual position to be loaded in the background
                RemoteViewsFrameLayout loadingView = null;
                final RemoteViewsMetaData metaData = mCache.getMetaData();
                synchronized (metaData) {
                    loadingView = metaData.createLoadingView(position, convertView, parent,
                            mCache, mLayoutInflater, mRemoteViewsOnClickHandler);
                }

                mRequestedViews.add(position, loadingView);
                mCache.queueRequestedPositionToLoad(position);
                loadNextIndexInBackground();

                return loadingView;
            }
        }
public intgetViewTypeCount()

        final RemoteViewsMetaData metaData = mCache.getMetaData();
        synchronized (metaData) {
            return metaData.viewTypeCount;
        }
private java.util.ArrayListgetVisibleWindow(int lower, int upper, int count)

        ArrayList<Integer> window = new ArrayList<Integer>();

        // In the case that the window is invalid or uninitialized, return an empty window.
        if ((lower == 0 && upper == 0) || lower < 0 || upper < 0) {
            return window;
        }

        if (lower <= upper) {
            for (int i = lower;  i <= upper; i++){
                window.add(i);
            }
        } else {
            // If the upper bound is less than the lower bound it means that the visible window
            // wraps around.
            for (int i = lower; i < count; i++) {
                window.add(i);
            }
            for (int i = 0; i <= upper; i++) {
                window.add(i);
            }
        }
        return window;
public booleanhandleMessage(android.os.Message msg)

        boolean result = false;
        switch (msg.what) {
        case sUnbindServiceMessageType:
            if (mServiceConnection.isConnected()) {
                mServiceConnection.unbind(mContext, mAppWidgetId, mIntent);
            }
            result = true;
            break;
        default:
            break;
        }
        return result;
public booleanhasStableIds()

        final RemoteViewsMetaData metaData = mCache.getMetaData();
        synchronized (metaData) {
            return metaData.hasStableIds;
        }
public booleanisDataReady()

        return mDataReady;
public booleanisEmpty()

        return getCount() <= 0;
private voidloadNextIndexInBackground()

        mWorkerQueue.post(new Runnable() {
            @Override
            public void run() {
                if (mServiceConnection.isConnected()) {
                    // Get the next index to load
                    int position = -1;
                    synchronized (mCache) {
                        int[] res = mCache.getNextIndexToLoad();
                        position = res[0];
                    }
                    if (position > -1) {
                        // Load the item, and notify any existing RemoteViewsFrameLayouts
                        updateRemoteViews(position, true);

                        // Queue up for the next one to load
                        loadNextIndexInBackground();
                    } else {
                        // No more items to load, so queue unbind
                        enqueueDeferredUnbindServiceMessage();
                    }
                }
            }
        });
public voidnotifyDataSetChanged()

        // Dequeue any unbind messages
        mMainQueue.removeMessages(sUnbindServiceMessageType);

        // If we are not connected, queue up the notifyDataSetChanged to be handled when we do
        // connect
        if (!mServiceConnection.isConnected()) {
            if (mNotifyDataSetChangedAfterOnServiceConnected) {
                return;
            }

            mNotifyDataSetChangedAfterOnServiceConnected = true;
            requestBindService();
            return;
        }

        mWorkerQueue.post(new Runnable() {
            @Override
            public void run() {
                onNotifyDataSetChanged();
            }
        });
private voidonNotifyDataSetChanged()

        // Complete the actual notifyDataSetChanged() call initiated earlier
        IRemoteViewsFactory factory = mServiceConnection.getRemoteViewsFactory();
        try {
            factory.onDataSetChanged();
        } catch (RemoteException e) {
            Log.e(TAG, "Error in updateNotifyDataSetChanged(): " + e.getMessage());

            // Return early to prevent from further being notified (since nothing has
            // changed)
            return;
        } catch (RuntimeException e) {
            Log.e(TAG, "Error in updateNotifyDataSetChanged(): " + e.getMessage());
            return;
        }

        // Flush the cache so that we can reload new items from the service
        synchronized (mCache) {
            mCache.reset();
        }

        // Re-request the new metadata (only after the notification to the factory)
        updateTemporaryMetaData();
        int newCount;
        ArrayList<Integer> visibleWindow;
        synchronized(mCache.getTemporaryMetaData()) {
            newCount = mCache.getTemporaryMetaData().count;
            visibleWindow = getVisibleWindow(mVisibleWindowLowerBound,
                    mVisibleWindowUpperBound, newCount);
        }

        // Pre-load (our best guess of) the views which are currently visible in the AdapterView.
        // This mitigates flashing and flickering of loading views when a widget notifies that
        // its data has changed.
        for (int i: visibleWindow) {
            // Because temporary meta data is only ever modified from this thread (ie.
            // mWorkerThread), it is safe to assume that count is a valid representation.
            if (i < newCount) {
                updateRemoteViews(i, false);
            }
        }

        // Propagate the notification back to the base adapter
        mMainQueue.post(new Runnable() {
            @Override
            public void run() {
                synchronized (mCache) {
                    mCache.commitTemporaryMetaData();
                }

                superNotifyDataSetChanged();
                enqueueDeferredUnbindServiceMessage();
            }
        });

        // Reset the notify flagflag
        mNotifyDataSetChangedAfterOnServiceConnected = false;
private voidprocessException(java.lang.String method, java.lang.Exception e)

        Log.e("RemoteViewsAdapter", "Error in " + method + ": " + e.getMessage());

        // If we encounter a crash when updating, we should reset the metadata & cache and trigger
        // a notifyDataSetChanged to update the widget accordingly
        final RemoteViewsMetaData metaData = mCache.getMetaData();
        synchronized (metaData) {
            metaData.reset();
        }
        synchronized (mCache) {
            mCache.reset();
        }
        mMainQueue.post(new Runnable() {
            @Override
            public void run() {
                superNotifyDataSetChanged();
            }
        });
private booleanrequestBindService()

        // Try binding the service (which will start it if it's not already running)
        if (!mServiceConnection.isConnected()) {
            mServiceConnection.bind(mContext, mAppWidgetId, mIntent);
        }

        // Remove any existing deferred-unbind messages
        mMainQueue.removeMessages(sUnbindServiceMessageType);
        return mServiceConnection.isConnected();
public voidsaveRemoteViewsCache()

        final RemoteViewsCacheKey key = new RemoteViewsCacheKey(
                new Intent.FilterComparison(mIntent), mAppWidgetId);

        synchronized(sCachedRemoteViewsCaches) {
            // If we already have a remove runnable posted for this key, remove it.
            if (sRemoteViewsCacheRemoveRunnables.containsKey(key)) {
                sCacheRemovalQueue.removeCallbacks(sRemoteViewsCacheRemoveRunnables.get(key));
                sRemoteViewsCacheRemoveRunnables.remove(key);
            }

            int metaDataCount = 0;
            int numRemoteViewsCached = 0;
            synchronized (mCache.mMetaData) {
                metaDataCount = mCache.mMetaData.count;
            }
            synchronized (mCache) {
                numRemoteViewsCached = mCache.mIndexRemoteViews.size();
            }
            if (metaDataCount > 0 && numRemoteViewsCached > 0) {
                sCachedRemoteViewsCaches.put(key, mCache);
            }

            Runnable r = new Runnable() {
                @Override
                public void run() {
                    synchronized (sCachedRemoteViewsCaches) {
                        if (sCachedRemoteViewsCaches.containsKey(key)) {
                            sCachedRemoteViewsCaches.remove(key);
                        }
                        if (sRemoteViewsCacheRemoveRunnables.containsKey(key)) {
                            sRemoteViewsCacheRemoveRunnables.remove(key);
                        }
                    }
                }
            };
            sRemoteViewsCacheRemoveRunnables.put(key, r);
            sCacheRemovalQueue.postDelayed(r, REMOTE_VIEWS_CACHE_DURATION);
        }
public voidsetRemoteViewsOnClickHandler(android.widget.RemoteViews.OnClickHandler handler)

        mRemoteViewsOnClickHandler = handler;
public voidsetVisibleRangeHint(int lowerBound, int upperBound)
This method allows an AdapterView using this Adapter to provide information about which views are currently being displayed. This allows for certain optimizations and preloading which wouldn't otherwise be possible.

        mVisibleWindowLowerBound = lowerBound;
        mVisibleWindowUpperBound = upperBound;
voidsuperNotifyDataSetChanged()

        super.notifyDataSetChanged();
private voidupdateRemoteViews(int position, boolean notifyWhenLoaded)

        IRemoteViewsFactory factory = mServiceConnection.getRemoteViewsFactory();

        // Load the item information from the remote service
        RemoteViews remoteViews = null;
        long itemId = 0;
        try {
            remoteViews = factory.getViewAt(position);
            itemId = factory.getItemId(position);
        } catch (RemoteException e) {
            Log.e(TAG, "Error in updateRemoteViews(" + position + "): " + e.getMessage());

            // Return early to prevent additional work in re-centering the view cache, and
            // swapping from the loading view
            return;
        } catch (RuntimeException e) {
            Log.e(TAG, "Error in updateRemoteViews(" + position + "): " + e.getMessage());
            return;
        }

        if (remoteViews == null) {
            // If a null view was returned, we break early to prevent it from getting
            // into our cache and causing problems later. The effect is that the child  at this
            // position will remain as a loading view until it is updated.
            Log.e(TAG, "Error in updateRemoteViews(" + position + "): " + " null RemoteViews " +
                    "returned from RemoteViewsFactory.");
            return;
        }

        int layoutId = remoteViews.getLayoutId();
        RemoteViewsMetaData metaData = mCache.getMetaData();
        boolean viewTypeInRange;
        int cacheCount;
        synchronized (metaData) {
            viewTypeInRange = metaData.isViewTypeInRange(layoutId);
            cacheCount = mCache.mMetaData.count;
        }
        synchronized (mCache) {
            if (viewTypeInRange) {
                ArrayList<Integer> visibleWindow = getVisibleWindow(mVisibleWindowLowerBound,
                        mVisibleWindowUpperBound, cacheCount);
                // Cache the RemoteViews we loaded
                mCache.insert(position, remoteViews, itemId, visibleWindow);

                // Notify all the views that we have previously returned for this index that
                // there is new data for it.
                final RemoteViews rv = remoteViews;
                if (notifyWhenLoaded) {
                    mMainQueue.post(new Runnable() {
                        @Override
                        public void run() {
                            mRequestedViews.notifyOnRemoteViewsLoaded(position, rv);
                        }
                    });
                }
            } else {
                // We need to log an error here, as the the view type count specified by the
                // factory is less than the number of view types returned. We don't return this
                // view to the AdapterView, as this will cause an exception in the hosting process,
                // which contains the associated AdapterView.
                Log.e(TAG, "Error: widget's RemoteViewsFactory returns more view types than " +
                        " indicated by getViewTypeCount() ");
            }
        }
private voidupdateTemporaryMetaData()

        IRemoteViewsFactory factory = mServiceConnection.getRemoteViewsFactory();

        try {
            // get the properties/first view (so that we can use it to
            // measure our dummy views)
            boolean hasStableIds = factory.hasStableIds();
            int viewTypeCount = factory.getViewTypeCount();
            int count = factory.getCount();
            RemoteViews loadingView = factory.getLoadingView();
            RemoteViews firstView = null;
            if ((count > 0) && (loadingView == null)) {
                firstView = factory.getViewAt(0);
            }
            final RemoteViewsMetaData tmpMetaData = mCache.getTemporaryMetaData();
            synchronized (tmpMetaData) {
                tmpMetaData.hasStableIds = hasStableIds;
                // We +1 because the base view type is the loading view
                tmpMetaData.viewTypeCount = viewTypeCount + 1;
                tmpMetaData.count = count;
                tmpMetaData.setLoadingViewTemplates(loadingView, firstView);
            }
        } catch(RemoteException e) {
            processException("updateMetaData", e);
        } catch(RuntimeException e) {
            processException("updateMetaData", e);
        }