Android : how to tell download service is available or not in android

i use android.app.DownloadManager to download some files. but if the phone do not start the download service, the app will crash. i try to write some code to judge if download service is available:

public  static  boolean  isServiceRunning(Context mContext) {
    boolean  isRunning = true ;
    int state = mContext.getPackageManager().getApplicationEnabledSetting("com.android.providers.downloads");

    if(state==PackageManager.COMPONENT_ENABLED_STATE_DISABLED||
    state==PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER
    ||state==PackageManager.COMPONENT_ENABLED_STATE_DISABLED_UNTIL_USED){

    // Cannot download using download manager
        isRunning = false;
    }

    return  isRunning;
}

but this piece of code does not work. it return false on my phone while download service is available. any one any ideas?