从Android中的PHP MySql仅获取最后一行

Question

Developing quiz application using Android - PHP MySql(DataBase) It's fetching only last row from the database, I want to implement and to fetch data one by one on next click.

So it will work like quiz

here is the recent code

protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);

        try
        {
            JSONObject json_data = new JSONObject(res); 

            quizID =(json_data.getString("quizID")); 
            question =(json_data.getString("question")); 
            choice1 =(json_data.getString("choice1")); 
            choice2 =(json_data.getString("choice2")); 
            choice3 =(json_data.getString("choice3")); 
            answer =(json_data.getString("answer")); 

            txtno.setText("No. " + quizID); 
            txtque.setText("" + question); 
            ropt0.setText("" + choice1); 
            ropt1.setText("" + choice2); 
            ropt2.setText("" + choice3); 
            ranswer.setText("" + answer);

        }
        catch(Exception e)
        {
            Log.e("Fail 3", e.toString());
        }   
    }   

PHP select.php code

<?php
$host='localhost';
$uname='root';
$pwd='';
$db="QuizDB";

$con = mysqli_connect($host,$uname,$pwd,$db) or die("connection failed");

$quizID=$_REQUEST['quizID'];
$question=$_REQUEST['question'];
$choice1=$_REQUEST['choice1'];
$choice2=$_REQUEST['choice2'];
$choice3=$_REQUEST['choice3'];
$answer=$_REQUEST['answer'];

$sql = "SELECT * FROM QuizQuestion"; 
$result = mysqli_query($con, $sql);

while($row=mysqli_fetch_array($result))
{
    $flag['quizID']=$row["quizID"];
    $flag['question']=$row["question"];
    $flag['choice1']=$row["choice1"];
    $flag['choice2']=$row["choice2"];
    $flag['choice3']=$row["choice3"];
    $flag['answer']=$row["answer"];
}

print(json_encode($flag));
mysqli_close($con);
?>

Please suggest some solution and how to implement next & previous functionality

Answer 1

Yes, that is because once you're having the flag object with, say first record in the table, you are not using it and just overwriting it with data in next record on the next execution of the while-loop.

Do something like:

while($row=mysqli_fetch_array($result))
{
    $flag['quizID']=$row["quizID"];
    $flag['question']=$row["question"];
    $flag['choice1']=$row["choice1"];
    $flag['choice2']=$row["choice2"];
    $flag['choice3']=$row["choice3"];
    $flag['answer']=$row["answer"];
    ...send flag object to wherever you  want...
}
mysqli_close($con);

To implement click for one-by-one results, keep a single counter for clicks for Next and Previous buttons and when one of them is pressed, send the value to a similar script where you can modify the query like:

$sql = "SELECT * FROM table ORDER BY quizID LIMIT "+counter+"-1,1"; 
$result = mysqli_query($con, $sql);

while($row=mysqli_fetch_array($result))
{
    $flag['quizID']=$row["quizID"];
    $flag['question']=$row["question"];
    $flag['choice1']=$row["choice1"];
    $flag['choice2']=$row["choice2"];
    $flag['choice3']=$row["choice3"];
    $flag['answer']=$row["answer"];
}

Similarly do a script for previous. Manage the counter well. Initially initialize it to 1. That is when Next is pressed increase the counter by 1 and decrease it by 1 when Previous is pressed.