Problems encountered during development: Java.lang.IllegalStateException:Unable to create directory:/STORAGE/SDCARD0/TRINEA/AA

However, file is created by File.mkdir (), which creates a new folder exception if the parent directory does not exist. So before downloading we'd better call the file's Mkdirs method recursively create a subdirectory

Mkdirs () can establish multi-level folders, mkdir () only create a level of folders, as follows:

New File ("/tmp/one/two/three"). Mkdirs ();

After execution, the Tmp/one/two/three level four directory is established

New File ("/tmp/one/two/three"). mkdir ();

No directories are established because the/tmp/one/two directory cannot be found and the result returns false