无法使用Apache POI编写Excel文件
我正在使用以下代码将数据写入到Excel文件中：
public class WriteExcellFile { public boolean saveExcelFile(Context context, String fileName) { // check if available and not read only if (!isExternalStorageAvailable() || isExternalStorageReadOnly()) { Log.d("FileUtils", "Storage not available or read only"); return false; } boolean success = false; //New Workbook Workbook wb = new HSSFWorkbook(); Cell c = null; //Cell style for header row CellStyle cs = wb.createCellStyle(); cs.setFillForegroundColor(HSSFColor.LIME.index); cs.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND); //New Sheet Sheet sheet1 = null; sheet1 = wb.createSheet("myOrder"); // Generate column headings Row row = sheet1.createRow(0); c = row.createCell(0); c.setCellValue("Item Number"); c.setCellStyle(cs); c = row.createCell(1); c.setCellValue("Quantity"); c.setCellStyle(cs); c = row.createCell(2); c.setCellValue("Price"); c.setCellStyle(cs); sheet1.setColumnWidth(0, (15 * 500)); sheet1.setColumnWidth(1, (15 * 500)); sheet1.setColumnWidth(2, (15 * 500)); // Create a path where we will place our List of objects on external storage File file = new File(context.getExternalFilesDir(null), fileName); FileOutputStream os = null; try { os = new FileOutputStream(file); wb.write(os); Log.d("FileUtils", "Writing file" + file); success = true; } catch (IOException e) { Log.d("FileUtils", "Error writing " + file, e); } catch (Exception e) { Log.d("FileUtils", "Failed to save file", e); } finally { try { if (null != os) os.close(); } catch (Exception ex) { } } return success; } public static boolean isExternalStorageReadOnly() { String extStorageState = Environment.getExternalStorageState(); if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(extStorageState)) { return true; } return false; } public static boolean isExternalStorageAvailable() { String extStorageState = Environment.getExternalStorageState(); if (Environment.MEDIA_MOUNTED.equals(extStorageState)) { return true; } return false; } } 代码在logcat上运行时没有任何错误，但是当我去到应该写入excel文件的文件夹时，文件夹是空的。 我也添加了Android Manifest文件的权限。
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
File file = new File(context.getExternalFilesDir(null), fileName);
在上面的行中，如果你用Environment.DIRECTORY_DOCUMENTSreplacenull，那么你的输出文件将被存储在那里。