安卓里的文件目录

 内部存储需要读写权限

getFilesDir()路径：/data/user/0/com.bobo.test/files

getDir("Bobo", Context.MODE_PRIVATE)路径：   /data/user/0/com.bobo.test/app_Bobo

getCacheDir()路径：     /data/user/0/com.bobo.test/cache

getDatabasePath()路径:    /data/user/0/com.bobo.test/databases/Bobo

getExternalCacheDir()路径：    /storage/emulated/0/Android/data/com.bobo.test/cache

getExternalFilesDir(null)路径:     /storage/emulated/0/Android/data/com.bobo.test/files

getExternalFilesDir("Bobo")路径:      /storage/emulated/0/Android/data/com.bobo.test/files/Bobo

Environment.getExternalStorageState()路径：    mounted                       //判断有没有挂载外部存储卡

Environment.getDataDirectory()路径：    /data

Environment.getExternalStoragePublicDirectory("Bobo")路径：    /storage/emulated/0/Bobo

Environment.getDownloadCacheDirectory()路径：     /cache

Environment.getExternalStorageDirectory()路径：      /storage/emulated/0

Environment.getRootDirectory()路径：    /system