Java tutorial
/* * Copyright 2012 The Stanford MobiSocial Laboratory * * 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 mobisocial.musubi.ui.widget; import java.io.FileDescriptor; import java.util.HashMap; import java.util.Map; import mobisocial.musubi.App; import mobisocial.musubi.R; import mobisocial.musubi.feed.iface.FeedRenderer; import mobisocial.musubi.model.DbLikeCache; import mobisocial.musubi.model.MApp; import mobisocial.musubi.model.MEncodedMessage; import mobisocial.musubi.model.MObject; import mobisocial.musubi.model.helpers.DatabaseManager; import mobisocial.musubi.obj.ObjHelpers; import mobisocial.musubi.provider.MusubiContentProvider; import mobisocial.musubi.provider.MusubiContentProvider.Provided; import mobisocial.socialkit.Obj; import org.json.JSONException; import org.json.JSONObject; import android.content.Context; import android.database.ContentObserver; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.net.Uri; import android.support.v4.content.AsyncTaskLoader; import android.support.v4.content.Loader; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.CursorAdapter; import android.widget.ImageView; import android.widget.TextView; public class DbObjCursorAdapter extends CursorAdapter { //Map<String, RenderManager> mRenderManagers; final Map<String, Integer> mViewTypes; static final int VIEW_TYPE_UNKNOWN = 0; final int mColumnIndexType; final Context mContext; final DatabaseManager mDbManager; final int mViewTypeCount; public DbObjCursorAdapter(Context context, Cursor cursor) { super(context, cursor, false); mContext = context; mDbManager = new DatabaseManager(context); mColumnIndexType = cursor.getColumnIndexOrThrow(MObject.COL_TYPE); String[] renderables = ObjHelpers.getRenderableTypes(); mViewTypeCount = renderables.length + 1; // renderables + generic int typeId = VIEW_TYPE_UNKNOWN; mViewTypes = new HashMap<String, Integer>(mViewTypeCount); mViewTypes.put("unknown", typeId++); for (String type : renderables) { mViewTypes.put(type, typeId++); } } @Override public View newView(Context context, Cursor c, ViewGroup parent) { throw new IllegalStateException("newView() not used in this adapter"); } @Override public void bindView(View v, Context context, Cursor c) { throw new IllegalStateException("bindView() not used in this adapter"); } boolean moveCursorToPosition(Cursor cursor, int position) { return cursor.moveToPosition(cursor.getCount() - position - 1); } @Override public int getItemViewType(int position) { Cursor cursor = getCursor(); moveCursorToPosition(cursor, position); String type = cursor.getString(mColumnIndexType); Integer typeId = mViewTypes.get(type); return (typeId == null) ? VIEW_TYPE_UNKNOWN : typeId; } @Override public int getViewTypeCount() { return mViewTypeCount; } public static class ViewHolder { public ViewGroup frame; public View error; public View objView; public ImageView senderIcon; public TextView senderName; public TextView timeText; public ImageView sendingIcon; public ImageView attachmentsIcon; public TextView attachmentsText; public TextView addContact; } @Override public View getView(int position, View convertView, ViewGroup parent) { Cursor cursor = getCursor(); if (!moveCursorToPosition(cursor, position)) { throw new IllegalStateException("couldn't move cursor to position " + position); } DbObjCursor row; if (convertView == null) { row = DbObjCursor.getInstance(mDbManager, cursor); } else { row = DbObjCursor.getInstance(mDbManager, cursor, (DbObjCursor) convertView.getTag(R.id.object_entry)); } FeedRenderer renderer = ObjHelpers.getFeedRenderer(row.type); ViewGroup objectMainView; ViewHolder viewHolder; if (convertView == null) { viewHolder = new ViewHolder(); LayoutInflater inflater = LayoutInflater.from(mContext); objectMainView = (ViewGroup) inflater.inflate(R.layout.objects_item, parent, false); viewHolder.frame = (ViewGroup) objectMainView.findViewById(R.id.object_content); viewHolder.objView = renderer.createView(mContext, viewHolder.frame); viewHolder.frame.addView(viewHolder.objView); viewHolder.error = objectMainView.findViewById(R.id.error_text); viewHolder.senderIcon = (ImageView) objectMainView.findViewById(R.id.icon); viewHolder.senderName = (TextView) objectMainView.findViewById(R.id.name_text); viewHolder.timeText = (TextView) objectMainView.findViewById(R.id.time_text); viewHolder.sendingIcon = (ImageView) objectMainView.findViewById(R.id.sending_icon); viewHolder.attachmentsIcon = (ImageView) objectMainView.findViewById(R.id.obj_attachments_icon); viewHolder.attachmentsText = (TextView) objectMainView.findViewById(R.id.obj_attachments); viewHolder.addContact = (TextView) objectMainView.findViewById(R.id.add_contact); objectMainView.setTag(R.id.holder, viewHolder); objectMainView.setTag(R.id.object_entry, row); } else { objectMainView = (ViewGroup) convertView; viewHolder = (ViewHolder) objectMainView.getTag(R.id.holder); } ObjHelpers.bindObjViewFrame(mContext, mDbManager, objectMainView, viewHolder, row); boolean allowInteractions = true; try { renderer.render(mContext, viewHolder.objView, row, allowInteractions); viewHolder.error.setVisibility(View.GONE); viewHolder.frame.setVisibility(View.VISIBLE); } catch (Exception e) { viewHolder.error.setVisibility(View.VISIBLE); viewHolder.frame.setVisibility(View.GONE); Log.e(getClass().getSimpleName(), "Error rendering type " + row.type, e); } return objectMainView; } public static Loader<Cursor> getLoaderForFeed(Context context, long feedId, int maxCount) { return new FeedObjectsCursorLoader(context, feedId, maxCount); } /** * A database-backed object with lazy-loaded accessors. */ public static class DbObjCursor implements Obj { public long objId; public String type; public long senderId; public String json; public boolean deleted; public long timestamp; public boolean sent; public String appId; public String appName; public int likeCount; public boolean localLike; private JSONObject mJson; /* lazy load extra fields */ private MObject mObject; private byte[] mRaw; private DatabaseManager mDbManager; /** * Remove dependency and destroy. */ @Deprecated public DbObjCursor(DatabaseManager db, long objId) { this(db, db.getObjectManager().getObjectForId(objId)); } /** * Remove dependency and destroy. */ @Deprecated public DbObjCursor(DatabaseManager db, MObject shim) { mDbManager = db; mObject = shim; this.objId = mObject.id_; this.type = mObject.type_; this.senderId = mObject.identityId_; this.json = mObject.json_; this.deleted = mObject.deleted_; this.timestamp = mObject.timestamp_; this.sent = true; // eh? MApp app = db.getAppManager().lookupApp(mObject.appId_); this.appId = app == null ? null : app.appId_; this.appName = app == null ? null : app.name_; this.likeCount = 0; // yeh. this.localLike = false; // guh. } static DbObjCursor getInstance(DatabaseManager dbManager, Cursor cursor) { DbObjCursor c = new DbObjCursor(); c.populate(dbManager, cursor); return c; } static DbObjCursor getInstance(DatabaseManager dbManager, Cursor cursor, DbObjCursor recycled) { recycled.populate(dbManager, cursor); return recycled; } private DbObjCursor() { } private void populate(DatabaseManager dbManager, Cursor c) { mDbManager = dbManager; objId = c.getLong(0); type = c.getString(1); senderId = c.getLong(2); json = (c.isNull(3)) ? null : c.getString(3); deleted = c.getInt(4) == 1; timestamp = c.getLong(5); if (c.isNull(6)) { sent = true; } else { sent = c.getInt(6) == 1; } appId = c.isNull(7) ? null : c.getString(7); appName = c.isNull(8) ? null : c.getString(8); likeCount = c.isNull(9) ? 0 : c.getInt(9); localLike = c.isNull(10) ? false : c.getInt(10) > 0; mJson = null; mObject = null; mRaw = null; } public DatabaseManager getDatabaseManager() { return mDbManager; } public JSONObject getJson() { if (mJson == null && json != null) { try { mJson = new JSONObject(json); } catch (JSONException e) { Log.e("DbObjCursor", "bad json", e); } } return mJson; } @Override public Integer getIntKey() { return getObject().intKey_; } @Override public byte[] getRaw() { if (mRaw == null) { mRaw = mDbManager.getObjectManager().getRawForId(objId); } return getObject().raw_; } public FileDescriptor getFileDescriptorForRaw() { return mDbManager.getObjectManager().getFileDescriptorForRaw(objId); } @Override public String getStringKey() { return getObject().stringKey_; } @Override public String getType() { return type; } private MObject getObject() { if (mObject == null) { mObject = mDbManager.getObjectManager().getObjectForId(objId); } return mObject; } } /** * Static library support version of the framework's {@link android.content.CursorLoader}. * Used to write apps that run on platforms prior to Android 3.0. When running * on Android 3.0 or above, this implementation is still used; it does not try * to switch to the framework's implementation. See the framework SDK * documentation for a class overview. */ static class FeedObjectsCursorLoader extends AsyncTaskLoader<Cursor> { static final String TAG = "FeedObjectsCursorLoader"; final ForceLoadContentObserver mObserver; final SQLiteDatabase mDb; long mFeedId; int mMaxCount; Cursor mCursor; /* Runs on a worker thread */ @Override public Cursor loadInBackground() { Cursor cursor = initCursor(); if (cursor != null) { // Ensure the cursor window is filled cursor.getCount(); registerContentObserver(cursor, mObserver); } return cursor; } /** * Registers an observer to get notifications from the content provider * when the cursor needs to be refreshed. */ void registerContentObserver(Cursor cursor, ContentObserver observer) { cursor.registerContentObserver(observer); } /* Runs on the UI thread */ @Override public void deliverResult(Cursor cursor) { if (isReset()) { // An async query came in while the loader is stopped if (cursor != null) { cursor.close(); } return; } Cursor oldCursor = mCursor; mCursor = cursor; if (isStarted()) { super.deliverResult(cursor); } if (oldCursor != null && oldCursor != cursor && !oldCursor.isClosed()) { oldCursor.close(); } } /** * Creates an empty unspecified CursorLoader. You must follow this with * calls to {@link #setUri(Uri)}, {@link #setSelection(String)}, etc * to specify the query to perform. */ public FeedObjectsCursorLoader(Context context, long feedId, int maxCount) { super(context); mDb = App.getDatabaseSource(context).getReadableDatabase(); mFeedId = feedId; mMaxCount = maxCount; mObserver = new ForceLoadContentObserver(); } /** * Starts an asynchronous load of the contacts list data. When the result is ready the callbacks * will be called on the UI thread. If a previous load has been completed and is still valid * the result may be passed to the callbacks immediately. * * Must be called from the UI thread */ @Override protected void onStartLoading() { if (mCursor != null) { deliverResult(mCursor); } if (takeContentChanged() || mCursor == null) { forceLoad(); } } /** * Must be called from the UI thread */ @Override protected void onStopLoading() { // Attempt to cancel the current load task if possible. cancelLoad(); } @Override public void onCanceled(Cursor cursor) { if (cursor != null && !cursor.isClosed()) { cursor.close(); } } @Override protected void onReset() { super.onReset(); // Ensure the loader is stopped onStopLoading(); if (mCursor != null && !mCursor.isClosed()) { mCursor.close(); } mCursor = null; } Cursor initCursor() { String[] selectionArgs = new String[] { Long.toString(mFeedId), Integer.toString(mMaxCount) }; Cursor c = mDb.rawQuery(getFeedObjectsQuery(), selectionArgs); c.setNotificationUri(getContext().getContentResolver(), MusubiContentProvider.uriForItem(Provided.FEEDS_ID, mFeedId)); return c; } static String sFeedObjectsQuery; String getFeedObjectsQuery() { if (sFeedObjectsQuery == null) { sFeedObjectsQuery = new StringBuilder(100).append("SELECT ").append(MObject.TABLE).append(".") .append(MObject.COL_ID).append(",").append(MObject.TABLE).append(".") .append(MObject.COL_TYPE).append(",").append(MObject.TABLE).append(".") .append(MObject.COL_IDENTITY_ID).append(",").append(MObject.TABLE).append(".") .append(MObject.COL_JSON).append(",").append(MObject.TABLE).append(".") .append(MObject.COL_DELETED).append(",").append(MObject.TABLE).append(".") .append(MObject.COL_TIMESTAMP).append(",").append(MEncodedMessage.TABLE).append(".") .append(MEncodedMessage.COL_PROCESSED).append(",").append(MApp.TABLE).append(".") .append(MApp.COL_APP_ID).append(",").append(MApp.TABLE).append(".").append(MApp.COL_NAME) .append(",").append(DbLikeCache.TABLE).append(".").append(DbLikeCache.COUNT).append(",") .append(DbLikeCache.TABLE).append(".").append(DbLikeCache.LOCAL_LIKE).append(" FROM ") .append(MObject.TABLE).append(" LEFT JOIN ").append(MEncodedMessage.TABLE).append(" ON ") .append(MObject.TABLE).append(".").append(MObject.COL_ENCODED_ID).append("=") .append(MEncodedMessage.TABLE).append(".").append(MEncodedMessage.COL_ID) .append(" LEFT JOIN ").append(MApp.TABLE).append(" ON ").append(MObject.TABLE).append(".") .append(MObject.COL_APP_ID).append("=").append(MApp.TABLE).append(".").append(MApp.COL_ID) .append(" LEFT JOIN ").append(DbLikeCache.TABLE).append(" ON ").append(MObject.TABLE) .append(".").append(MObject.COL_ID).append("=").append(DbLikeCache.TABLE).append(".") .append(DbLikeCache.PARENT_OBJ).append(" WHERE ").append(MObject.TABLE).append(".") .append(MObject.COL_RENDERABLE).append("=1 AND ").append(MObject.TABLE).append(".") .append(MObject.COL_PARENT_ID).append(" is null AND ").append(MObject.TABLE).append(".") .append(MObject.COL_FEED_ID).append(" =?").append(" ORDER BY ") .append(MObject.COL_LAST_MODIFIED_TIMESTAMP).append(" DESC LIMIT ?").toString(); } return sFeedObjectsQuery; } } }