Android系统中，当插入耳机或者拔出耳机，会发出一个广播。

这个广播必须是在代码里面注册Receiver才有效，在xml中添加intentfilter没效。

private static BroadcastReceiver mHeadSetReceiver =  new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals(Intent.ACTION_HEADSET_PLUG)) {
            int state = intent.getIntExtra("state", -1);
            switch (state) {
            case 0:
                mIsHeadSetPlugged = false;
                break;
            case 1:
                mIsHeadSetPlugged = true;
                break;
            default:
                Log.d(TAG, "未知状态");
                break;
            }

        }
    }

};

public void onResume() {
    IntentFilter filter = new IntentFilter();
    filter.addAction(Intent.ACTION_HEADSET_PLUG);
    mContext.registerReceiver(mHeadSetReceiver, filter);
}

Android监听耳机是否插入