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package pro.dbro.ble.ui.adapter; /* w w w . j a v a 2 s . com*/ /* * Copyright (C) 2013 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. */ /* * Copyright (C) 2014 flzyup@ligux.com * * 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. * */ import android.content.Context; import android.database.ContentObserver; import android.database.Cursor; import android.database.DataSetObserver; import android.os.Handler; import android.support.v7.widget.RecyclerView; import android.widget.Filter; import android.widget.FilterQueryProvider; import android.widget.Filterable; /** * Version 1.0 * <p/> * Date: 2014-07-07 19:53 * Author: flzyup@ligux.com * <p/> * Copyright 2009-2014 LiGux.com. */ public abstract class RecyclerViewCursorAdapter<VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> implements Filterable, CursorFilter.CursorFilterClient { /** * Call when bind view with the cursor * * @param holder * @param cursor */ public abstract void onBindViewHolder(VH holder, Cursor cursor); /** * This field should be made private, so it is hidden from the SDK. * {@hide} */ protected boolean mDataValid; /** * The current cursor */ protected Cursor mCursor; /** * This field should be made private, so it is hidden from the SDK. * {@hide} */ protected Context mContext; /** * The row id column */ protected int mRowIDColumn; /** * This field should be made private, so it is hidden from the SDK. * {@hide} */ protected ChangeObserver mChangeObserver; /** * This field should be made private, so it is hidden from the SDK. * {@hide} */ protected DataSetObserver mDataSetObserver; /** * This field should be made private, so it is hidden from the SDK. * {@hide} */ protected CursorFilter mCursorFilter; /** * This field should be made private, so it is hidden from the SDK. * {@hide} */ protected FilterQueryProvider mFilterQueryProvider; /** * If set the adapter will register a content observer on the cursor and will call * {@link #onContentChanged()} when a notification comes in. Be careful when * using this flag: you will need to unset the current Cursor from the adapter * to avoid leaks due to its registered observers. This flag is not needed * when using a CursorAdapter with a * {@link android.content.CursorLoader}. */ public static final int FLAG_REGISTER_CONTENT_OBSERVER = 0x02; /** * Recommended constructor. * * @param c The cursor from which to get the data. * @param context The context * @param flags Flags used to determine the behavior of the adapter; * Currently it accept {@link #FLAG_REGISTER_CONTENT_OBSERVER}. */ public RecyclerViewCursorAdapter(Context context, Cursor c, int flags) { init(context, c, flags); } void init(Context context, Cursor c, int flags) { boolean cursorPresent = c != null; mCursor = c; mDataValid = cursorPresent; mContext = context; mRowIDColumn = cursorPresent ? c.getColumnIndexOrThrow("_id") : -1; if ((flags & FLAG_REGISTER_CONTENT_OBSERVER) == FLAG_REGISTER_CONTENT_OBSERVER) { mChangeObserver = new ChangeObserver(); mDataSetObserver = new MyDataSetObserver(); } else { mChangeObserver = null; mDataSetObserver = null; } if (cursorPresent) { if (mChangeObserver != null) c.registerContentObserver(mChangeObserver); if (mDataSetObserver != null) c.registerDataSetObserver(mDataSetObserver); } setHasStableIds(true); } /** * Returns the cursor. * * @return the cursor. */ @Override public Cursor getCursor() { return mCursor; } /** * @see android.support.v7.widget.RecyclerView.Adapter#getItemCount() */ @Override public int getItemCount() { if (mDataValid && mCursor != null) { return mCursor.getCount(); } else { return 0; } } /** * @param position Adapter position to query * @return * @see android.support.v7.widget.RecyclerView.Adapter#getItemId(int) */ @Override public long getItemId(int position) { if (mDataValid && mCursor != null) { if (mCursor.moveToPosition(position)) { return mCursor.getLong(mRowIDColumn); } else { return 0; } } else { return 0; } } @Override public void onBindViewHolder(VH holder, int position) { if (!mDataValid) { throw new IllegalStateException("this should only be called when the cursor is valid"); } if (!mCursor.moveToPosition(position)) { throw new IllegalStateException("couldn't move cursor to position " + position); } onBindViewHolder(holder, mCursor); } /** * Change the underlying cursor to a new cursor. If there is an existing cursor it will be * closed. * * @param cursor The new cursor to be used */ public void changeCursor(Cursor cursor) { Cursor old = swapCursor(cursor); if (old != null) { old.close(); } } /** * Swap in a new Cursor, returning the old Cursor. Unlike * {@link #changeCursor(Cursor)}, the returned old Cursor is <em>not</em> * closed. * * @param newCursor The new cursor to be used. * @return Returns the previously set Cursor, or null if there wasa not one. * If the given new Cursor is the same instance is the previously set * Cursor, null is also returned. */ public Cursor swapCursor(Cursor newCursor) { if (newCursor == mCursor) { return null; } Cursor oldCursor = mCursor; if (oldCursor != null) { if (mChangeObserver != null) oldCursor.unregisterContentObserver(mChangeObserver); if (mDataSetObserver != null) oldCursor.unregisterDataSetObserver(mDataSetObserver); } mCursor = newCursor; if (newCursor != null) { if (mChangeObserver != null) newCursor.registerContentObserver(mChangeObserver); if (mDataSetObserver != null) newCursor.registerDataSetObserver(mDataSetObserver); mRowIDColumn = newCursor.getColumnIndexOrThrow("_id"); mDataValid = true; // notify the observers about the new cursor notifyDataSetChanged(); } else { mRowIDColumn = -1; mDataValid = false; // notify the observers about the lack of a data set notifyDataSetChanged(); // notifyDataSetInvalidated(); } return oldCursor; } /** * <p>Converts the cursor into a CharSequence. Subclasses should override this * method to convert their results. The default implementation returns an * empty String for null values or the default String representation of * the value.</p> * * @param cursor the cursor to convert to a CharSequence * @return a CharSequence representing the value */ public CharSequence convertToString(Cursor cursor) { return cursor == null ? "" : cursor.toString(); } /** * Runs a query with the specified constraint. This query is requested * by the filter attached to this adapter. * <p/> * The query is provided by a * {@link android.widget.FilterQueryProvider}. * If no provider is specified, the current cursor is not filtered and returned. * <p/> * After this method returns the resulting cursor is passed to {@link #changeCursor(Cursor)} * and the previous cursor is closed. * <p/> * This method is always executed on a background thread, not on the * application's main thread (or UI thread.) * <p/> * Contract: when constraint is null or empty, the original results, * prior to any filtering, must be returned. * * @param constraint the constraint with which the query must be filtered * @return a Cursor representing the results of the new query * @see #getFilter() * @see #getFilterQueryProvider() * @see #setFilterQueryProvider(android.widget.FilterQueryProvider) */ public Cursor runQueryOnBackgroundThread(CharSequence constraint) { if (mFilterQueryProvider != null) { return mFilterQueryProvider.runQuery(constraint); } return mCursor; } public Filter getFilter() { if (mCursorFilter == null) { mCursorFilter = new CursorFilter(this); } return mCursorFilter; } /** * Returns the query filter provider used for filtering. When the * provider is null, no filtering occurs. * * @return the current filter query provider or null if it does not exist * @see #setFilterQueryProvider(android.widget.FilterQueryProvider) * @see #runQueryOnBackgroundThread(CharSequence) */ public FilterQueryProvider getFilterQueryProvider() { return mFilterQueryProvider; } /** * Sets the query filter provider used to filter the current Cursor. * The provider's * {@link android.widget.FilterQueryProvider#runQuery(CharSequence)} * method is invoked when filtering is requested by a client of * this adapter. * * @param filterQueryProvider the filter query provider or null to remove it * @see #getFilterQueryProvider() * @see #runQueryOnBackgroundThread(CharSequence) */ public void setFilterQueryProvider(FilterQueryProvider filterQueryProvider) { mFilterQueryProvider = filterQueryProvider; } /** * Called when the {@link ContentObserver} on the cursor receives a change notification. * The default implementation provides the auto-requery logic, but may be overridden by * sub classes. * * @see ContentObserver#onChange(boolean) */ protected abstract void onContentChanged(); private class ChangeObserver extends ContentObserver { public ChangeObserver() { super(new Handler()); } @Override public boolean deliverSelfNotifications() { return true; } @Override public void onChange(boolean selfChange) { onContentChanged(); } } private class MyDataSetObserver extends DataSetObserver { @Override public void onChanged() { mDataValid = true; notifyDataSetChanged(); } @Override public void onInvalidated() { mDataValid = false; notifyDataSetChanged(); // notifyDataSetInvalidated(); } } }