如何在Android应用程序中的文本文件中保存文本字段（用户输入）数据

Question

我希望无论我在应用程序的编辑文本字段中写入的内容是否自动保存在.txt文件中。这样我就可以从那里直接检索这个文件，并从一个按钮发送到任何一个文件。 我的问题是，我如何直接以.txt格式保存。

Answer 1

只需获取EditText的内容并将其保存到文件中即可。 Google提供了一个documentation for this last part。

Answer 2

此代码片段将在文本更改时将文本复制到字符串中，并调用函数以写入应用程序的私有文件目录。

String YourTextString;  
    YourTextField.addTextChangedListener(new TextWatcher() { 
      @Override 
      public void onTextChanged(CharSequence arg0, int arg1, int arg2,int arg3) { 
       YourTextString = YourTextField.getText().toString(); 
       writeToFile(YourTextString); 
      } 
      @Override 
      public void afterTextChanged(Editable s) {  
      } 
      @Override 
      public void beforeTextChanged(CharSequence s, int start, int count,int after) {   
      } 
     }); 
public void writeToFile(String data) { 
    try { 
     OutputStreamWriter MyOutputStreamWriter = new OutputStreamWriter(mContext.openFileOutput("YourFileName.txt", Context.MODE_PRIVATE)); 
     MyOutputStreamWriter.append(data); 
     MyOutputStreamWriter.close(); 
    } 
    catch (IOException e) { 
     Log.e("Exception", "File write failed: " + e.toString()); 
    } 
} 

编辑： 如果你想从文件中读取，你可以使用此功能（如果path参数为空，代码将读取的私人文件目录中的文件，如果你给它它会读取你指定的文件）：

public String readFromFile(String path) { 
    String ret = ""; 
    if(path==""){ 
     try { 
      InputStream inputStream = mContext.openFileInput(FileName); 

      if (inputStream != null) { 
       InputStreamReader inputStreamReader = new InputStreamReader(inputStream); 
       BufferedReader bufferedReader = new BufferedReader(inputStreamReader); 
       String receiveString = ""; 
       StringBuilder stringBuilder = new StringBuilder(); 

       while ((receiveString = bufferedReader.readLine()) != null) { 
        stringBuilder.append(receiveString).append("\n"); 
       } 

       inputStream.close(); 
       ret = stringBuilder.toString(); 
      } 
     } 
     catch (FileNotFoundException e) { 
      Log.e("login activity", "File not found: " + e.toString()); 
     } catch (IOException e) { 
      Log.e("login activity", "Can not read file: " + e.toString()); 
     } 
    } 
    else 
    { 
     File file = new File(path); 
     String receiveString = ""; 
     StringBuilder stringBuilder = new StringBuilder(); 
     try { 
      BufferedReader buf = new BufferedReader(new FileReader(file)); 
      while ((receiveString = buf.readLine()) != null) { 
       stringBuilder.append(receiveString).append("\n"); 
      } 
      buf.close(); 
      ret = stringBuilder.toString(); 
     } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 
    return ret; 
}