Question

我试过了为登录做一个活动我曾经使用过AsyncTask 我试试随着错误的凭据它没有显示任何弹出错误的密码。我已经尝试了所有验证的可能性，但当它进入AsyncTask它匹配参数但从不发布任何东西。所以我应该在哪里添加Alertdialog，使其匹配结果带参数和返回。我还需要获取json字符串。它是在onpostExecute方法或doinbackground中检查的。我是android pls help的新手。

    public class FetchTask extends AsyncTask<String, Void, String> {
    protected void onPostExecute(String result)
    {
        Emp emp=new Emp();
        if(result==null && !(result.equals("0")) )
        {
            alert.showAlertDialog(MainActivity.this, "Login failed..", "Wrong credential please enter again", false);

            //   Toast.makeText(getApplicationContext(), "Wrong credentials Please enter again", Toast.LENGTH_SHORT).show();
        }
        List<Emp> data=new ArrayList<>();
        try {
         //   JSONArray jArray = new JSONArray(result);
           // for(int i=0;i<jArray.length();i++) {
                JSONObject json_data = new JSONObject(result);
                emp.validstatus=json_data.getInt("validstatus");
                emp.roleid=json_data.getInt("roleid");
                emp.empid=json_data.getString("empid");
                data.add(emp);
                if (emp.validstatus==1 && emp.roleid==14)
                {
                    Intent intent=new Intent(MainActivity.this,Second.class);
                   intent.putExtra("empid",emp.empid);
                    startActivity(intent);
                }
            else
                {
                    alert.showAlertDialog(MainActivity.this, "Login failed..", "Wrong credential please enter again", false);

                }


            } catch (JSONException e) {
            e.printStackTrace();
        }


    }

    @Override
    protected String doInBackground(String... params) {
        Log.e("reached","reaching");
        Log.v(TAG,"Before intent object");
        HttpURLConnection urlConnection = null;
        BufferedReader reader = null;
       // String[] loginVal = params[0].split(";");
       //String build="http://192.168.0.102/login.php?user_name="+params[0].split(";")[0]+"&password="+params[0].split(";")[1];
       //String build="http://192.168.1.10:8080/upstest/rest/profile/loginvalidate.sp?";
       String build= null;
        try {
            build = Util.getProperty("login_url",getApplicationContext());
        } catch (IOException e) {
            e.printStackTrace();
        }
        String build1="username="+params[0].split(";")[0]+"&password="+params[0].split(";")[1];
        String x=build+build1;
        Log.e("the url ", x);
        try {
            URL url = new URL(x);
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.connect();
            InputStream inputStream = urlConnection.getInputStream();

            StringBuffer buffer = new StringBuffer();
            if (inputStream == null)
            {
                Log.e("Data", "can't fetch");
            }
            reader = new BufferedReader(new InputStreamReader(inputStream));
            Log.e("Bufferreader",String.valueOf(reader));
            String line;
            while ((line = reader.readLine()) != null) {
                // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                // But it does make debugging a *lot* easier if you print out the completed
                // buffer for debugging.
                buffer.append(line + "\n");
            }
           // Intent intent = new Intent(getApplicationContext(), Second.class);
            if (!buffer.toString().contains("failed"))
            {
           //     startActivity(intent);
            return  buffer.toString();
             // finish();
            }
            else{

                return "login incorrect";
                }
        }
        catch(Exception e){
            e.printStackTrace();
        }
        return null;
    }
}

Answer 1

只需将result==null更改为result!=null，因为您在登录错误条件或登录失败条件时返回"login incorrect"，并且您正在检查result==null，这是不正确的你正在返回任何字符串。结果不能为空。

AsyncTask不显示错误凭据的弹出窗口

1 个答案: