btn_ok.setOnClickListener(new OnClickListener() {

                              @Override

                              publicvoid onClick(View v) {

                                        String user =et_user.getText().toString().trim();

                                        String pwd =et_pwd.getText().toString().trim();

                                        if(user.isEmpty()||pwd.isEmpty()){

                                                  Toast.makeText(getApplicationContext(),"不能为空", 200).show();

                                        }else{

                                                  String name="data.txt";

                                                  String content=user+"="+pwd;

                                                  try {

                                                   FileOutputStream fos=openFileOutput(name,MODE_PRIVATE);

                                                   fos.write(content.getBytes());

                                                   fos.close();

                                                   Toast.makeText(getApplicationContext(),"保存成功", 200).show();

                                                  }catch (Exception e) {

                                                            //TODO Auto-generated catch block

                                                            e.printStackTrace();

                                                  }

                                        }

                              }

                    });

btn_show.setOnClickListener(new OnClickListener() {

                              @Override

                              publicvoid onClick(View v) {

                                        String name="data.txt";

                                        try {

                                                  FileInputStream fis=openFileInput(name);

                                                  BufferedReader br=newBufferedReader(new InputStreamReader(fis));

                                                  //读取文档的数据

                                                  String content = br.readLine();

                                                  //拆分字符串

                                                  String[] strs = content.split("=");

                                                  //显示的数据

                                                  if(!content.isEmpty()){

                                                            et_user.setText(strs[0]);

                                                            et_pwd.setText(strs[1]);

                                                  }

                                        }catch (Exception e) {

                                                  //TODO Auto-generated catch block

                                                  e.printStackTrace();

                                        }          

                              }

                    });