xref: /frameworks/support/v4/jellybean-mr2/android/support/v4/media/TransportMediatorJellybeanMR2.java

/*
 * 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.
 */

package android.support.v4.media;

import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.AudioManager;
import android.media.RemoteControlClient;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewTreeObserver;

public class TransportControllerJellybeanMR2 {
    final Context mContext;
    final AudioManager mAudioManager;
    final View mTargetView;
    final KeyCallback mKeyCallback;
    final String mReceiverAction;
    final IntentFilter mReceiverFilter;
    final Intent mIntent;
    final ViewTreeObserver.OnWindowAttachListener mWindowAttachListener =
            new ViewTreeObserver.OnWindowAttachListener() {
                @Override
                public void onWindowAttached() {
                    windowAttached();
                }
                @Override
                public void onWindowDetached() {
                    windowDetached();
                }
            };
    final ViewTreeObserver.OnWindowFocusChangeListener mWindowFocusListener =
            new ViewTreeObserver.OnWindowFocusChangeListener() {
                @Override
                public void onWindowFocusChanged(boolean hasFocus) {
                    if (hasFocus) gainFocus();
                    else loseFocus();
                }
            };
    final BroadcastReceiver mMediaButtonReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            try {
                KeyEvent event = (KeyEvent)intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
                mKeyCallback.handleKey(event);
            } catch (ClassCastException e) {
                Log.w("TransportController", e);
            }
        }
    };

    PendingIntent mPendingIntent;
    RemoteControlClient mRemoteControl;
    boolean mFocused;

    public interface KeyCallback {
        public void handleKey(KeyEvent key);
    }

    public TransportControllerJellybeanMR2(Context context, AudioManager audioManager,
            View view, KeyCallback keyCallback) {
        mContext = context;
        mAudioManager = audioManager;
        mTargetView = view;
        mKeyCallback = keyCallback;
        mReceiverAction = context.getPackageName() + ":transport:" + System.identityHashCode(this);
        mIntent = new Intent(mReceiverAction);
        mIntent.setPackage(context.getPackageName());
        mReceiverFilter = new IntentFilter();
        mReceiverFilter.addAction(mReceiverAction);
        mTargetView.getViewTreeObserver().addOnWindowAttachListener(mWindowAttachListener);
        mTargetView.getViewTreeObserver().addOnWindowFocusChangeListener(mWindowFocusListener);
    }

    public Object getRemoteControlClient() {
        return mRemoteControl;
    }

    public void destroy() {
        windowDetached();
        mTargetView.getViewTreeObserver().removeOnWindowAttachListener(mWindowAttachListener);
        mTargetView.getViewTreeObserver().removeOnWindowFocusChangeListener(mWindowFocusListener);
    }

    void windowAttached() {
        mContext.registerReceiver(mMediaButtonReceiver, mReceiverFilter);
        mPendingIntent = PendingIntent.getBroadcast(mContext, 0, mIntent,
                PendingIntent.FLAG_CANCEL_CURRENT);
        mRemoteControl = new RemoteControlClient(mPendingIntent);
    }

    void gainFocus() {
        if (!mFocused) {
            mFocused = true;
            mAudioManager.registerMediaButtonEventReceiver(mPendingIntent);
            mAudioManager.registerRemoteControlClient(mRemoteControl);
        }
    }

    void loseFocus() {
        if (mFocused) {
            mFocused = false;
            mAudioManager.unregisterRemoteControlClient(mRemoteControl);
            mAudioManager.unregisterMediaButtonEventReceiver(mPendingIntent);
        }
    }

    void windowDetached() {
        loseFocus();
        if (mPendingIntent != null) {
            mContext.unregisterReceiver(mMediaButtonReceiver);
            mPendingIntent.cancel();
            mPendingIntent = null;
            mRemoteControl = null;
        }
    }
}