SD卡路径在Android中正确的路径？

Question

I don't know if the problem is the incorrect sdcard path or something else, but in my application i have a button that onClick it create a copy of the app folder in the sdcard (of course needs root). To me it works, i have stock android 4.4 with nexus 5 and it creates a folder named BackupApps in where there is the folder app with all apk files but some users tells me that the folder is not created. Here the code:

first; i created the path in sdcard with the new folder that will created:

final File customfolder=new File(Environment.getExternalStorageDirectory().toString()+File.separator+"BackupApps");

then the onClick code:

copy.setOnClickListener(new OnClickListener() {         
            public void onClick(View v){        
                        Process checkroot = null;
                        String rootcheck ="su";
                        String cd = "cd /";
                        String comando ="su cd cp -av /data/app "+customfolder;
                        customfolder.mkdir();
                        try {
                            Process copy = Runtime.getRuntime().exec(comando);
                            Toast.makeText(getActivity(), appmanagerfragment.this.getResources().getString(R.string.toastcopysi), 
                                    Toast.LENGTH_LONG).show();
                            Log.v("All In One Copia tag","Ok, folder copied in "+customfolder);

                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                    }                  

        });

any idea?

Answer 1

I do not think your commando is correct, becuse su cd cp... makes no real sense. You should remove cd from commando

Answer 2

At first, there is a constructor for File, File(String,String) , that adds the separator by itself.

At second, I'm not sure there's su in a non-rooted android. In addition, some command line keys may not be supported in Android, for example, ls -l works, but 'ls -lF' does not. I suggest you run adb shell and perform the commands from the command line; when you know they do what you want, you move them to the code.

BTW, shell commands in the command line are separated with ; .

In general, I if the task is to copy a directory, I suggest (pardon) searching google with "copy directory java" or "copy directory android stackoverflow" and borrowing someone else's code. For example, this or this . And add the permission to write to sd card to your application. (BTW, this may be the reason why the subprocess failed.)