common/src/java/com/example/android/common/midi/MidiOutputPortSelector.java

/*
 * Copyright (C) 2015 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.example.android.common.midi;

import android.app.Activity;
import android.media.midi.MidiDevice;
import android.media.midi.MidiDeviceInfo;
import android.media.midi.MidiManager;
import android.media.midi.MidiOutputPort;
import android.media.midi.MidiSender;
import android.os.Handler;
import android.os.Looper;
import android.util.Log;

import java.io.IOException;

/**
 * Manages a Spinner for selecting a MidiOutputPort.
 */
public class MidiOutputPortSelector extends MidiPortSelector {
    private MidiOutputPort mOutputPort;
    private MidiDispatcher mDispatcher = new MidiDispatcher();
    private MidiDevice mOpenDevice;

    /**
     * @param midiManager
     * @param activity
     * @param spinnerId ID from the layout resource
     */
    public MidiOutputPortSelector(MidiManager midiManager, Activity activity,
            int spinnerId) {
        super(midiManager, activity, spinnerId, MidiDeviceInfo.PortInfo.TYPE_OUTPUT);
    }

    @Override
    public void onPortSelected(final MidiPortWrapper wrapper) {
        Log.i(MidiConstants.TAG, "onPortSelected: " + wrapper);
        close();

        final MidiDeviceInfo info = wrapper.getDeviceInfo();
        if (info != null) {
            mMidiManager.openDevice(info, new MidiManager.OnDeviceOpenedListener() {

                    @Override
                public void onDeviceOpened(MidiDevice device) {
                    if (device == null) {
                        Log.e(MidiConstants.TAG, "could not open " + info);
                    } else {
                        mOpenDevice = device;
                        mOutputPort = device.openOutputPort(wrapper.getPortIndex());
                        if (mOutputPort == null) {
                            Log.e(MidiConstants.TAG,
                                    "could not open output port for " + info);
                            return;
                        }
                        mOutputPort.connect(mDispatcher);
                    }
                }
            }, null);
            // Don't run the callback on the UI thread because openOutputPort might take a while.
        }
    }

    @Override
    public void onClose() {
        try {
            if (mOutputPort != null) {
                mOutputPort.disconnect(mDispatcher);
            }
            mOutputPort = null;
            if (mOpenDevice != null) {
                mOpenDevice.close();
            }
            mOpenDevice = null;
        } catch (IOException e) {
            Log.e(MidiConstants.TAG, "cleanup failed", e);
        }
    }

    /**
     * You can connect your MidiReceivers to this sender. The user will then select which output
     * port will send messages through this MidiSender.
     * @return a MidiSender that will send the messages from the selected port.
     */
    public MidiSender getSender() {
        return mDispatcher.getSender();
    }

}