1、需要申请手机读写的权限
AndroidMani.xml里面配置权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
我们一般采用RxPermission来申请权限
RxPermissions(this).requestEachCombined(Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE).subscribe {when {it.granted -> {}it.shouldShowRequestPermissionRationale -> {}else -> {}}}