| /* |
| * Copyright (C) 2011 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.android.browser.util; |
| |
| import android.content.Context; |
| import android.database.Cursor; |
| import android.os.Handler; |
| import android.os.HandlerThread; |
| import android.os.Message; |
| import android.os.Process; |
| import android.os.SystemProperties; |
| import android.util.Log; |
| import android.view.View; |
| import android.view.ViewGroup; |
| import android.widget.Adapter; |
| import android.widget.BaseAdapter; |
| import android.widget.CursorAdapter; |
| |
| import com.android.browser.R; |
| |
| import java.lang.ref.WeakReference; |
| |
| public abstract class ThreadedCursorAdapter<T> extends BaseAdapter { |
| |
| private static final String LOGTAG = "BookmarksThreadedAdapter"; |
| private static final boolean DEBUG = false; |
| |
| private Context mContext; |
| private Object mCursorLock = new Object(); |
| private CursorAdapter mCursorAdapter; |
| private T mLoadingObject; |
| private Handler mLoadHandler; |
| private Handler mHandler; |
| private int mSize; |
| private boolean mHasCursor; |
| private long mGeneration; |
| |
| private class LoadContainer { |
| WeakReference<View> view; |
| int position; |
| T bind_object; |
| Adapter owner; |
| boolean loaded; |
| long generation; |
| } |
| |
| public ThreadedCursorAdapter(Context context, Cursor c) { |
| mContext = context; |
| mHasCursor = (c != null); |
| mCursorAdapter = new CursorAdapter(context, c, 0) { |
| |
| @Override |
| public View newView(Context context, Cursor cursor, ViewGroup parent) { |
| throw new IllegalStateException("not supported"); |
| } |
| |
| @Override |
| public void bindView(View view, Context context, Cursor cursor) { |
| throw new IllegalStateException("not supported"); |
| } |
| |
| @Override |
| public void notifyDataSetChanged() { |
| super.notifyDataSetChanged(); |
| mSize = getCount(); |
| mGeneration++; |
| ThreadedCursorAdapter.this.notifyDataSetChanged(); |
| } |
| |
| @Override |
| public void notifyDataSetInvalidated() { |
| super.notifyDataSetInvalidated(); |
| mSize = getCount(); |
| mGeneration++; |
| ThreadedCursorAdapter.this.notifyDataSetInvalidated(); |
| } |
| |
| }; |
| mSize = mCursorAdapter.getCount(); |
| HandlerThread thread = new HandlerThread("threaded_adapter_" + this, |
| Process.THREAD_PRIORITY_BACKGROUND); |
| thread.start(); |
| mLoadHandler = new Handler(thread.getLooper()) { |
| @SuppressWarnings("unchecked") |
| @Override |
| public void handleMessage(Message msg) { |
| if (DEBUG) { |
| Log.d(LOGTAG, "loading: " + msg.what); |
| } |
| loadRowObject(msg.what, (LoadContainer) msg.obj); |
| } |
| }; |
| mHandler = new Handler() { |
| @Override |
| public void handleMessage(Message msg) { |
| @SuppressWarnings("unchecked") |
| LoadContainer container = (LoadContainer) msg.obj; |
| if (container == null) { |
| return; |
| } |
| View view = container.view.get(); |
| if (view == null |
| || container.owner != ThreadedCursorAdapter.this |
| || container.position != msg.what |
| || view.getWindowToken() == null |
| || container.generation != mGeneration) { |
| return; |
| } |
| container.loaded = true; |
| bindView(view, container.bind_object); |
| } |
| }; |
| } |
| |
| @Override |
| public int getCount() { |
| return mSize; |
| } |
| |
| @Override |
| public Cursor getItem(int position) { |
| return (Cursor) mCursorAdapter.getItem(position); |
| } |
| |
| @Override |
| public long getItemId(int position) { |
| synchronized (mCursorLock) { |
| return getItemId(getItem(position)); |
| } |
| } |
| |
| private void loadRowObject(int position, LoadContainer container) { |
| if (container == null |
| || container.position != position |
| || container.owner != ThreadedCursorAdapter.this |
| || container.view.get() == null) { |
| return; |
| } |
| synchronized (mCursorLock) { |
| Cursor c = (Cursor) mCursorAdapter.getItem(position); |
| if (c == null || c.isClosed()) { |
| return; |
| } |
| container.bind_object = getRowObject(c, container.bind_object); |
| } |
| mHandler.obtainMessage(position, container).sendToTarget(); |
| } |
| |
| @Override |
| public View getView(int position, View convertView, ViewGroup parent) { |
| if (convertView == null) { |
| convertView = newView(mContext, parent); |
| } |
| @SuppressWarnings("unchecked") |
| LoadContainer container = (LoadContainer) convertView.getTag(R.id.load_object); |
| if (container == null) { |
| container = new LoadContainer(); |
| container.view = new WeakReference<View>(convertView); |
| convertView.setTag(R.id.load_object, container); |
| } |
| if (container.position == position |
| && container.owner == this |
| && container.loaded |
| && container.generation == mGeneration) { |
| bindView(convertView, container.bind_object); |
| } else { |
| bindView(convertView, cachedLoadObject()); |
| if (mHasCursor) { |
| container.position = position; |
| container.loaded = false; |
| container.owner = this; |
| container.generation = mGeneration; |
| mLoadHandler.obtainMessage(position, container).sendToTarget(); |
| } |
| } |
| return convertView; |
| } |
| |
| private T cachedLoadObject() { |
| if (mLoadingObject == null) { |
| mLoadingObject = getLoadingObject(); |
| } |
| return mLoadingObject; |
| } |
| |
| public void changeCursor(Cursor cursor) { |
| mLoadHandler.removeCallbacksAndMessages(null); |
| mHandler.removeCallbacksAndMessages(null); |
| synchronized (mCursorLock) { |
| mHasCursor = (cursor != null); |
| mCursorAdapter.changeCursor(cursor); |
| } |
| } |
| |
| public abstract View newView(Context context, ViewGroup parent); |
| public abstract void bindView(View view, T object); |
| public abstract T getRowObject(Cursor c, T recycleObject); |
| public abstract T getLoadingObject(); |
| protected abstract long getItemId(Cursor c); |
| } |