android 删除文件以及递归删除文件夹

 private void deleteDirectory(File file) {
     if (file.isFile()) {
         file.delete();
         return;
     } 

     if(file.isDirectory()){
         File[] childFiles = file.listFiles();
         if (childFiles == null || childFiles.length == 0) {
             file.delete();
             return;
         } 

         for (int i = 0; i < childFiles.length; i++) {
            deleteDirectory(childFiles[i]);
         }
         file.delete();
     }
 }