[android]使用线控耳机来操控应用功能

使用线控耳机来操控应用功能

实现原理：通过广播拦截来实现。

（一）定义1个广播拦截器，用来拦截线控耳机按键产生的广播事件。

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.KeyEvent;

public class MediaButtonReceiver extends BroadcastReceiver {
	
	/**
	 * Handler
	 */
	private Handler handler;
	
	/**
	 * 构造器.
	 * @param handler
	 */
	public MediaButtonReceiver(Handler handler) {
		this.handler = handler;
	}

	@Override
	public void onReceive(Context context, Intent intent) {
		boolean isActionMediaButton = Intent.ACTION_MEDIA_BUTTON.equals(intent.getAction());
		if(!isActionMediaButton) return;
		KeyEvent event = (KeyEvent)intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
		if(event==null) return;
		
		boolean isActionUp = (event.getAction()==KeyEvent.ACTION_UP);
		if(!isActionUp) return;
		
		int keyCode = event.getKeyCode();
		long eventTime = event.getEventTime()-event.getDownTime();//按键按下到松开的时长
		Message msg = Message.obtain();
		msg.what = 100;
		Bundle data = new Bundle();
		data.putInt("key_code", keyCode);
		data.putLong("event_time", eventTime);
		msg.setData(data);
		handler.sendMessage(msg);
		
		//终止广播(不让别的程序收到此广播，免受干扰)
		abortBroadcast();
	}
}

（二）在主程序的处理：

（1）定义并注册广播服务

//初始化Handler对象
    	MyHandler handler = new MyHandler();
    	//初始化媒体(耳机)广播对象.
    	MediaButtonReceiver mediaButtonReceiver = new MediaButtonReceiver(handler);
    	//注册媒体(耳机)广播对象
    	IntentFilter intentFilter = new IntentFilter(Intent.ACTION_MEDIA_BUTTON);
    	intentFilter.setPriority(100);
    	registerReceiver(mediaButtonReceiver, intentFilter);

（2）定义MyHandler和处理广播发回的消息：

private class MyHandler extends Handler{
		@Override
		public void handleMessage(Message msg) {
			int what = msg.what;
			switch(what){
			case 100://单击按键广播
				Bundle data = msg.getData();
				//按键值
				int keyCode = data.getInt("key_code");
				//按键时长
				long eventTime = data.getLong("event_time");
				//设置超过2000毫秒，就触发长按事件
				boolean isLongPress = (eventTime>2000);
				
				switch(keyCode){
				case KeyEvent.KEYCODE_HEADSETHOOK://播放或暂停
				case KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE://播放或暂停
					playOrPause();
					break;
					
				//短按=播放下一首音乐，长按=当前音乐快进
				case KeyEvent.KEYCODE_MEDIA_NEXT:
					if(isLongPress){
						fastNext(1);//自定义
					}else{
						playNext();//自定义
					}
					break;
					
				//短按=播放上一首音乐，长按=当前音乐快退	
				case KeyEvent.KEYCODE_MEDIA_PREVIOUS:
					if(isLongPress){
						fastPrevious(1);//自定义
					}else{
						playPrevious();//自定义
					}
					break;
				}
				
				break;
			default://其他消息-则扔回上层处理
				super.handleMessage(msg);
			}
		}
	}

（3）应用程序退出的时候，别忘了取消注册的广播拦截器。

unregisterReceiver(mediaButtonReceiver);