1、需要申請手機讀寫的權限

AndroidMani.xml里面配置權限

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

我們一般采用RxPermission來申請權限

RxPermissions(this).requestEachCombined(Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE).subscribe {when {it.granted -> {}it.shouldShowRequestPermissionRationale -> {}else -> {}}}