Question

您好我想创建一个文件并在其中写入一些数据，之后我想为该文件分配只读权限，这样其他任何人都无法修改它。

我写完了部分内容但我不知道如何设置只读权限和删除其他所有权限我试过setReadOnly（）;但它不起作用。

如果有任何解决方案，请告诉我。先谢谢你...

我试过跟随，但它不起作用

String currentDateTimeString;
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH.mm.ss");//date format
            currentDateTimeString = sdf.format(new Date());//current date
            File recordFolder = new File(Environment.getExternalStorageDirectory(), "WBS/Record");
            recordFolder.mkdirs(); // <----make a folder
            File file = new File(recordFolder, currentDateTimeString+".xml");//create the images

            File dbtest =new File("/data/data/com/ami/wbs/databases/WBS");

            if(!dbtest.exists())
            {
              // what to do if it does exist
            //  Toast.makeText(getApplicationContext(), "DB is present", Toast.LENGTH_LONG).show();
            }
            else
            {
              // what to do if it doesn't exist
                //Toast.makeText(getApplicationContext(), "DB is not present", Toast.LENGTH_LONG).show();
            }

                database = new DB_Adapter(getApplicationContext(), "WBS", null, 1);
                FileWriter filewrite = null;
                //BufferedWriter filewrite = null;
                try {

                    //filewrite = new BufferedWriter(new OutputStreamWriter(openFileOutput(currentDateTimeString+".xml", MODE_PRIVATE)));
                    filewrite = new FileWriter(file,true);
                    filewrite.write("<?xml version='1.0' ?>");
                    filewrite.write("<Resultset>");
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                SQLiteDatabase db=database.getReadableDatabase();
                Cursor c = db.rawQuery("Select CONSUMER_ID,METER_NO,PREV_READING,CURR_READING from CONSUMER;", null);

                if(c.moveToNext())
                {
                //  Toast.makeText(getApplicationContext(),"Table found", Toast.LENGTH_SHORT).show();
                }
                else
                {
                    Toast.makeText(getApplicationContext(),"Table not found", Toast.LENGTH_SHORT).show();
                }

                c.moveToFirst();
                do
                {

                    String consumerid=c.getString(c.getColumnIndex("CONSUMER_ID"));
                    String meterno=c.getString(c.getColumnIndex("METER_NO"));
                    String currentreading=c.getString(c.getColumnIndex("CURR_READING"));

                    try {
                        filewrite.write("<consumer>"
                                        +"<consumerid>"+consumerid+"</consumerid>"
                                        +"<meter>"+meterno+"</meter>"
                                         +"<curread>"+currentreading+"</curread></consumer>");
                         filewrite.write("</Resultset>");
                          filewrite.close();

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

                }while(c.moveToNext());
     file.setReadOnly();
                Toast.makeText(getApplicationContext(), "Export file successfully", Toast.LENGTH_SHORT).show();

Answer 1

如果文件位于内部存储空间（例如getFilesDir()），则默认情况下只读取该文件。

如果文件位于外部存储设备（例如Environment.getExternalStorageDirectory()），则AFAIK无法更改权限位以使其成为只读。

如何为文件分配只读权限

1 个答案: