Question

我正尝试在php中创建一个简单的程序，该程序读取带有歌曲的文本文件，然后在屏幕上通过每首歌曲旁边的删除按钮将它们打印出来，然后在您单击删除按钮时，歌曲应删除。新文件将写入txt文件，并应在屏幕上刷新。我的代码仅在第二次单击后才能工作。第一次单击实际上确实会修改txt文件，但屏幕上的代码不会刷新。

谢谢

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>My Music</title>
<body>
<h1>My Music</h1>
<p>My Library</p>

<?php
//read file
$myFile = "test.txt";
//file to array
$lines  = file($myFile);
//set array length
$length = count($lines);
//print array on screen with delete button
for ($i = 0; $i < $length; $i++) {
    echo $lines[$i] . '<form action="index.php" method="post">
                     <button type="submit" name="test" value="' . $i . '">Delete</button><br><br></form>';
}


//after clicking delete box remove song from array 
if (isset($_POST['test'])) {
    //getting song number to remove
    $songNumber = $_POST['test'];
    //removing song from original array  
    array_splice($lines, $songNumber, 1);
    //open test.txt again
    $myFile2 = fopen("test.txt", "w") or die("Unable to open file!");
    //set updated array length
    $length = count($lines);
    //write array to test.txt
    for ($i = 0; $i < $length; $i++) {
        $txt = $lines[$i];
        fwrite($myFile2, $txt);
    }
}
?>
</body>
</html>

我正在使用的文本文件

1. turkish march
2. claire de lune
3. symphony no. 9
4. swan lake
5. imperial march
6. helter skelter

Answer 1

查看代码执行的顺序。首先，它从文件中读取并显示数据。然后从文件中删除一行。之后文件已经显示。

只需交换事件顺序：

if (isset($_POST['test'])) {
    // perform your delete
}

// Display the contents of the file
$myFile = "test.txt";
// etc.
for ($i = 0; $i < $length; $i++) {
    // ...
}

Answer 2

您正在读取文件，然后删除标题，当您单击按钮时，您会读取未修改的版本，然后对其进行修改，这就是它在第二次刷新时起作用的原因。或单击。更改代码的顺序。

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>My Music</title>
<body>
<h1>My Music</h1>
<p>My Library</p>

<?php

//after clicking delete box remove song from array 
// remove file first if needed...
if (isset($_POST['test'])) {
    //getting song number to remove
    $songNumber = $_POST['test'];
    //removing song from original array  
    array_splice($lines, $songNumber, 1);
    //open test.txt again
    $myFile2 = fopen("test.txt", "w") or die("Unable to open file!");
    //set updated array length
    $length = count($lines);
    //write array to test.txt
    for ($i = 0; $i < $length; $i++) {
        $txt = $lines[$i];
        fwrite($myFile2, $txt);
    }
}

//read file
$myFile = "test.txt";
//file to array
$lines  = file($myFile);
//set array length
$length = count($lines);
//print array on screen with delete button
for ($i = 0; $i < $length; $i++) {
    echo $lines[$i] . '<form action="index.php" method="post">
                     <button type="submit" name="test" value="' . $i . '">Delete</button><br><br></form>';
}



?>
</body>
</html>

代码仅在第二次单击后才能工作，简单的php

2 个答案: