无法在android上编写文件

Question

我一直在尝试在android上编写PDF文件，当我使用内部存储时，它显示没有错误，但我无法看到创建的文件，如果我更改路径到外部存储我得到即使我已在我的清单文件中给予权限，但拒绝权限。 我有创建一个类，我从活动调用写入文件，它从数据库中获取数据。 这是代码。

 public boolean createPdfFile(String path, Employee employee,String month,Context context){ 
    boolean status=false; 
    if(path!=null && employee!=null){ 
     Document document=new Document(); 
     try{ 
      if(!Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())){ 
       Toast.makeText(this, "External SD card not mounted", Toast.LENGTH_LONG).show(); 
      } 
      File sdCard=Environment.getExternalStorageDirectory(); 
      File file=new File(sdCard,month+"_"+employee.getEmployeeName()+".pdf"); 
      PdfWriter writer=PdfWriter.getInstance(document,new FileOutputStream(file)); 
      writer.setEncryption(employee.getDateOfBirth().getBytes(),employee.getEmployeeName().getBytes(), PdfWriter.ALLOW_PRINTING,PdfWriter.ENCRYPTION_AES_128); 
      document.open(); 
      Paragraph p=new Paragraph(); 
      p.add("Payslip for the month of January"); 
      p.setFont(new Font(Font.FontFamily.TIMES_ROMAN, 12, Font.BOLD, new BaseColor(1, 1, 1))); 
      p.setAlignment(Element.ALIGN_CENTER); 
      document.add(p); 
      PdfPTable table=new PdfPTable(2); 
      table.setWidthPercentage(100); //Width 100% 
      table.setSpacingBefore(10f); //Space before table 
      table.setSpacingAfter(10f); //Space after table 
      float[] columnWidths = {1.5f, 1.5f}; 
      table.setWidths(columnWidths); 
      table.addCell("Employee Code"); 
      table.addCell(employee.getEmployeeID()); 
      table.addCell("Department"); 
      table.addCell(employee.getDepartment().getDepartmentName()); 
      table.addCell("Date of Birth"); 
      table.addCell(employee.getDateOfBirth()); 
      table.addCell("Date of Joining"); 
      table.addCell(employee.getDateOfJoining()); 
      table.addCell("Employee Name"); 
      table.addCell(employee.getEmployeeName()); 
      document.add(table); 
      document.close(); 
      writer.close(); 
      status=true; 
     }catch (FileNotFoundException e) { 
      status=false; 
      Log.e("PDF exception aaa",e.getMessage()); 
     }catch (DocumentException e) { 
      status=false; 
      Log.e("PDF exception abc",e.getMessage()); 
     } catch (IOException e) { 
      status=false; 
      Log.e("PDF exception",e.getMessage()); 
     } 
    } 
    return status; 
} 

Answer 1

如果您正在开发API级别23或更新版本，则需要明确询问用户的权限。

参见：https://developer.android.com/training/permissions/requesting.html#perm-check