JExcelApi在安卓系统中不起作用

Question

当我单击该按钮时，没有任何反应；我已经在清单文件中授予了外部写权限。怎么啦？提前谢谢你。

(代码乱七八糟，我稍后再整理，抱歉)

下面是我的代码：

     excelButton.setOnClickListener(
            new Button.OnClickListener(){
                public void onClick(View v) {
String s = excelName.getText().toString();

                    Label label;


                        String Fnamexls = s + ".xls";
                        File sdCard =   Environment.getExternalStorageDirectory();
                        File directory = new File(sdCard.getAbsolutePath() + "/newfolder");
                        directory.mkdirs();
                        File file = new File(directory, Fnamexls);
excelWriter f = new excelWriter();
                        WorkbookSettings wbSettings = new WorkbookSettings();

                        wbSettings.setLocale(new Locale("en", "EN"));

                        WritableWorkbook workbook;
                        try {

                            workbook = Workbook.createWorkbook(file, wbSettings);
                            //workbook.createSheet("Report", 0);
                            WritableSheet sheet = workbook.createSheet("First Sheet", 0);
                         for(int x = 0; x<MainActivity.kolonAdi.size();x++){
                             for(int y = 0; y<MainActivity.rowAdet;y++){
                              label =   f.excelWriterClass(x,y,enterValues.table[x][y].toString());
                                 try {
                                     sheet.addCell(label);

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







                            workbook.write();
                            try {
                                workbook.close();
                            } catch (WriteException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }
                            //createExcel(excelSheet);
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }


                }});   

这是标签分类；

 package angrybabysoftware.statisticalsoftware;

 import jxl.write.Label;



 public class excelWriter {


public Label excelWriterClass (int a, int b, String c){

    Label label = new Label(a,b,c);

    return label;
}


 }