Android - 如何從網址讀取文本文件？

Question

我上傳了一個文本文件（* .txt）到服務器，現在我想讀取文本文件...

我試過這個例子沒有運氣。

ArrayList<String> urls=new ArrayList<String>(); //to read each line 
TextView t; //to show the result 
try { 
     // Create a URL for the desired page 
     URL url = new URL("mydomainname.de/test.txt"); //My text file location 
     // Read all the text returned by the server 
     BufferedReader in = new BufferedReader(new  InputStreamReader(url.openStream())); 

    t=(TextView)findViewById(R.id.TextView1); 
    String str; 
    while ((str = in.readLine()) != null) { 
     urls.add(str); 


    } 
    in.close(); 
    } catch (MalformedURLException e) { 
    } catch (IOException e) { 
} 
t.setText(urls.get(0)); // My TextFile has 3 lines 

應用程序被關閉本身...... 可以向上的域名？應該有IP嗎？ 我發現while循環沒有執行。 因爲如果我把t.setText *放在while循環中沒有錯誤，並且TextView是空的。 LogCat錯誤：http://textuploader.com/5iijr它突出顯示的行t.setText(urls.get(0));

在此先感謝！

Answer 1

嘗試使用HttpURLConnection類或OKHTTP請求得到的信息，在這裏試試這個：

永遠做任何形式在後臺線程聯網否則Android將拋出一個NetworkOnMainThread異常

new Thread(new Runnable(){ 

    public void run(){ 


    ArrayList<String> urls=new ArrayList<String>(); //to read each line 
    //TextView t; //to show the result, please declare and find it inside onCreate() 



    try { 
     // Create a URL for the desired page 
     URL url = new URL("http://somevaliddomain.com/somevalidfile"); //My text file location 
     //First open the connection 
     HttpURLConnection conn=(HttpURLConnection) url.openConnection(); 
     conn.setConnectTimeout(60000); // timing out in a minute 

     BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream())); 

     //t=(TextView)findViewById(R.id.TextView1); // ideally do this in onCreate() 
     String str; 
     while ((str = in.readLine()) != null) { 
      urls.add(str); 
     } 
     in.close(); 
    } catch (Exception e) { 
     Log.d("MyTag",e.toString()); 
    } 

    //since we are in background thread, to post results we have to go back to ui thread. do the following for that 

    Activity.this.runOnUiThread(new Runnable(){ 
     public void run(){ 
      t.setText(urls.get(0)); // My TextFile has 3 lines 
     } 
    }); 

    } 
}).start(); 

Answer 2

的

試試這個。這個對我有用。

private static String readText(){ 
    String link="http://.../file.txt"; 
    ArrayList<String> al=new ArrayList<>(); 

    try{ 
     URL url = new URL(link); 
     URLConnection conn = url.openConnection(); 
     conn.setDoOutput(true); 
     conn.connect(); 

     InputStream is = conn.getInputStream(); 
     InputStreamReader isr = new InputStreamReader(is, "UTF-8"); 
     BufferedReader br = new BufferedReader(isr); 
     String line; 

     try { 
      while ((line = br.readLine()) != null) { 
       al.add(line); 
      } 
     } finally { 
      br.close(); 
     } 
    }catch (IOException e){ 
     e.printStackTrace(); 
    } 
    return al.get(0); 
} 

所以，

t.setText(readText()); 

Answer 3

1）互聯網的權限添加到您的清單文件。 2）確保你在不同的線程中啓動你的代碼。

下面是對我很好的代碼片段。

public List<String> getTextFromWeb(String urlString) 
    { 
     URLConnection feedUrl; 
     List<String> placeAddress = new ArrayList<>(); 

     try 
     { 
      feedUrl = new URL(urlString).openConnection(); 
      InputStream is = feedUrl.getInputStream(); 

      BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));   
      String line = null; 

      while ((line = reader.readLine()) != null) // read line by line 
      { 
       placeAddress.add(line); // add line to list 
      } 
      is.close(); // close input stream 

      return placeAddress; // return whatever you need 
     } 
     catch (Exception e) 
     { 
      e.printStackTrace(); 
     } 

     return null; 
    } 

我們的閱讀器的功能是準備好了，讓我們用另一個線程

  new Thread(new Runnable() 
      { 
       public void run() 
       { 
        final List<String> addressList = getTextFromWeb("http://www.google.com/sometext.txt"); // format your URL 
        runOnUiThread(new Runnable() 
        { 
         @Override 
         public void run() 
         { 
          //update ui 
         } 
        }); 
       } 
      }).start();