Application使用及注意

文章会不停修改和完善。

1、kotlin application 单例

class App : Application(){    companion object {        private  var instance: Application? = null        //var btDev: BtDevice? = null        fun instance() = instance!!    }    override fun onCreate() {        super.onCreate()        instance = this        //btDev = BtDevice.getInstance(instance!!)    }}