| /* |
| * Copyright (C) 2012 Google Inc. |
| * Licensed to 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.mail.ui; |
| |
| import android.app.Activity; |
| import android.app.FragmentTransaction; |
| import android.os.Handler; |
| |
| import com.android.mail.utils.LogTag; |
| import com.android.mail.utils.LogUtils; |
| |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| /** |
| * A thin wrapper of {@link Handler} to run a callback in UI thread. Any callback posted to this |
| * handler is guarantee to run inside {@link Activity} life cycle. However, it can be dropped if the |
| * {@link Activity} has been stopped. This handler is safe to use with {@link FragmentTransaction}. |
| * |
| * @author phamm |
| */ |
| public class UiHandler { |
| private final Handler mHandler = new Handler(); |
| private boolean mEnabled = true; |
| private final static String LOG_TAG = LogTag.getLogTag(); |
| |
| /** Number of {@link Runnable} in the queue. */ |
| private AtomicInteger mCount = new AtomicInteger(0); |
| |
| public void post(final Runnable r) { |
| if (mEnabled) { |
| mCount.incrementAndGet(); |
| mHandler.post(new Runnable() { |
| @Override |
| public void run() { |
| mCount.decrementAndGet(); |
| r.run(); |
| } |
| }); |
| } else { |
| LogUtils.d(LOG_TAG, "UiHandler is disabled in post(). Dropping Runnable."); |
| } |
| } |
| |
| public void postDelayed(final Runnable r, long delayMillis) { |
| if (mEnabled) { |
| mCount.incrementAndGet(); |
| mHandler.postDelayed(new Runnable() { |
| @Override |
| public void run() { |
| mCount.decrementAndGet(); |
| r.run(); |
| } |
| }, delayMillis); |
| } else { |
| LogUtils.d(LOG_TAG, "UiHandler is disabled in postDelayed(). Dropping Runnable."); |
| } |
| } |
| |
| public void removeCallbacks(Runnable r) { |
| mHandler.removeCallbacks(r); |
| } |
| |
| public void setEnabled(boolean enabled) { |
| mEnabled = enabled; |
| if (!mEnabled) { |
| int count = mCount.getAndSet(0); |
| if (count > 0) { |
| LogUtils.e(LOG_TAG, "Disable UiHandler. Dropping %d Runnables.", count); |
| } |
| mHandler.removeCallbacksAndMessages(null); |
| } |
| } |
| |
| /** |
| * @return whether the {@link UiHandler} is enabled. It's safe to edit UI if the |
| * {@link UiHandler} is enabled. |
| */ |
| public boolean isEnabled() { |
| return mEnabled; |
| } |
| } |