Android 9 Development Cookbook - Third Edition

Checking available space

One issue consistent between internal and external storage is limited space. If you know how much space you will need ahead of time, you can call the getFreeSpace() method on the File object. (getTotalSpace() will return the total space.) Here is a simple example, using the call to getFreeSpace():

if (Environment.getExternalStorageDirectory().getFreeSpace() < RQUIRED_FILE_SPACE) { 
    //Not enough space 
} else { 
    //We have enough space 
}