我怎樣才能得到.txt文件逐行讀取

Question

我在SDcard上有一個文件 - 「file.txt」包含單獨行中的電話號碼。 我想先顯示行，然後如果我按下按鈕，第二行應顯示在TextView中，第一行應該消失。 我有代碼，只是讀取txt文件的內容，並在TextView中完全插入所有行：

當按下按鈕時，應如何將此代碼更改爲串行輸出以下行？

File sdcard = Environment.getExternalStorageDirectory(); 
    File file = new File(sdcard,"file.txt"); 
    StringBuilder text = new StringBuilder(); 
     try { 
     BufferedReader br = new BufferedReader(new FileReader(file)); 
     String line; 

     while ((line = br.readLine()) != null) { 
      line = br.readLine(); 
      text.append(line); 
      text.append('\n'); 
     } 
    } 
    catch (IOException e) { 
    } 
    tv.setText(text); 

當按下按鈕時，應如何將此代碼更改爲串行輸出以下行？

Answer 1

您可以將文件的內容存儲在ArrayList < String>中，然後在按下按鈕時，將TextView中的文本更改爲列表中的另一個文本。喜歡的東西：

1. 讀文件，然後在列表存儲：在按下按鈕

   //make this a class member variable 
   List<String> numbers = new ArrayList<String>(); 
   
   while((line = br.readLine()) != null) { 
       //store each line in our list as separate entry 
       numbers.add(line); 
   } 
   

2. 更新的TextView：

   //make this a class member variable 
   //this is being used to get the line from list 
   int currentLine = 0; 
   
   button.setOnClickListener(new View.OnClickListener() { 
       @Override 
       public void onClick(View v) { 
        //set the text 
        tv.setText(numbers.get(currentLine)); 
   
        //increment currentLine 
        currentLine++; 
   
        //make sure we don't go beyond the number of lines stored in the list 
        //so if we reach the last index, we start from the beginning 
        if (currentLine == numbers.size()) { 
         currentLine = 0; 
        } 
       } 
   });