检查USB是否连接

//

 /**
     * 检测USB是否连接
     */
    private BroadcastReceiver mUSBReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
                LogUtil.i("插入USB，继续线程", "log.txt");
                UpdatePresenter.IOSource oldIOSrc = mUpdatePresenter.getIOSource();
                LogUtil.i("连接USB" + mUpdatePresenter.getIOSource() + "，mIOSource:" + oldIOSrc);
                mUpdatePresenter.setIOSource(UpdatePresenter.IOSource.RS232);
                ToastUtil.showLong(App.application, "连接USB");
            }
            if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
                boolean isSuccess = mUpdatePresenter.restoreBackupIOSource();
                if (!isSuccess) {
                    mUpdatePresenter.setIOSource(UpdatePresenter.IOSource.BLUETOOTH);
                }
                LogUtil.i("断开USB，暂停线程", "log.txt");
                ToastUtil.showLong(App.application, "断开USB");
            }
        }
    };