未定義的變量錯誤TTS PHP腳本

Question

我試圖讓這個代碼工作，但它不會。請有人幫助我。這是第一個文件，tts.php：

<?php 
class TextToSpeech { 
    public $mp3data; 
    function __construct($text="") { 
     $text = trim($text); 
     if(!empty($text)) { 
      $text = urlencode($text); 
      $this->mp3data = file_get_contents("http://translate.google.com/translate_tts?tl=en&q={$text}"); 
     } 
    } 

    function setText($text) { 
     $text = trim($text); 
     if(!empty($text)) { 
      $text = urlencode($text); 
      $this->mp3data = file_get_contents("http://translate.google.com/translate_tts?tl=en&q={$text}"); 
      return $mp3data; 
     } else { return false; } 
    } 

    function saveToFile($filename) { 
     $filename = trim($filename); 
     if(!empty($filename)) { 
      return file_put_contents($filename,$this->mp3data); 
     } else { return false; } 
    } 
} 
?> 

第二個文件，index.php文件：

<?php 
require "tts.php"; 
$tts = new TextToSpeech(); 
$tts->setText("Hello World!"); 
$tts->saveToFile("voice.mp3"); 
?> 

這是錯誤：

*我上運行的代碼本地主機

Answer 1

return $mp3data;應該return $this->mp3data;

Answer 2

return $this->mp3data; 

的

代替

return $mp3data; 

Answer 3

你應該改變行

return $mp3data; 

要

return $this->mp3data; 

Answer 4

線27大概是這條線在setText()功能...

return $mp3data; 

，它應該是

return $this->mp3data;