ListView不显示来自文本文件的文本

Question

我有一个活动的列表视图，我想显示从文本文件中读取的信息。这是上述活动的代码（类）：

public class ViewData extends AppCompatActivity { 

    //code to show strings from file 
    private ArrayList<String> readFromFile(Context context) { 

     ArrayList<String> receiveString=new ArrayList<String>(); 

     try { 
      InputStream inputStream = context.openFileInput(AddDataActivity.FileName); 

      if (inputStream != null) { 
       InputStreamReader inputStreamReader = new InputStreamReader(inputStream); 
       BufferedReader bufferedReader = new BufferedReader(inputStreamReader); 
       String tempString=""; 
       while ((tempString=bufferedReader.readLine()) != null) { 

        receiveString.add(tempString); 
       } 

       inputStream.close(); 

      } 
     } 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()); 
     } 

     return receiveString; 
    } 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_view_data); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); 
     fab.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
         .setAction("Action", null).show(); 
      } 
     }); 

     ListView listView=(ListView)findViewById(R.id.listView); 

     // Define a new Adapter 
     // First parameter - Context 
     // Second parameter - Layout for the row 
     // Third parameter - ID of the TextView to which the data is written 
     // Forth - the Array of data 

     ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, 
       android.R.layout.simple_list_item_1, android.R.id.text1,readFromFile(getApplicationContext())); 


     // Assign adapter to ListView 
     listView.setAdapter(adapter); 

     // ListView Item Click Listener 
//  listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
// 
//   @Override 
//   public void onItemClick(AdapterView<?> parent, View view, 
//         int position, long id) { 
// 
//    // ListView Clicked item index 
//    int itemPosition  = position; 
// 
//    // ListView Clicked item value 
//    String itemValue = (String) listView.getItemAtPosition(position); 
// 
//    // Show Alert 
//    Toast.makeText(getApplicationContext(), 
//      "Position :"+itemPosition+" ListItem : " +itemValue , Toast.LENGTH_LONG) 
//      .show(); 
// 
//   } 
// 
//  }); 



    } 


} 

我有一个应该触发此活动（启动）菜单按钮和的onCreate，我想从文件中读取和显示文本内容我在另一项活动中保存到文件中。不过，我目前看到下面的结果，这似乎总是相同的，无论什么样的变化被保存到提到的文本文件：

这是我的布局内容视图：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:context="mhd.myupliftingmate.ViewData" 
    tools:showIn="@layout/activity_view_data"> 

    <ListView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/listView" 
     android:layout_alignParentTop="true" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" /> 
</RelativeLayout> 

这是我的主菜单布局，其中的活性ViewData的叫：

<menu xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    tools:context="mhd.myupliftingmate.MainActivity"> 
    <item 
     android:id="@+id/action_settings" 
     android:orderInCategory="100" 
     android:title="@string/action_settings" 
     android:icon="@drawable/settings" 
     app:showAsAction="ifRoom" 
     /> 
    <item app:showAsAction="ifRoom" 
     android:orderInCategory="101" 
     android:title="Add Data" 
     android:id="@+id/action_addData" 
     android:onClick="openAddActivity" 
     android:icon="@drawable/input" 
/> 
    <item 
     android:orderInCategory="102" 
     android:title="View Data" 
     android:id="@+id/action_viewData" 
     android:onClick="openViewActivity" 
     android:icon="@drawable/text" 
     app:showAsAction="ifRoom" 
/> 


</menu> 

我也加入了文件编写代码，以防有可能是该问题。

public class AddDataActivity extends AppCompatActivity { 

    public static final String FileName="data.txt"; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_add_data); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); 
     fab.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
         .setAction("Action", null).show(); 
      } 
     }); 
    } 

    public void saveToFile(View view) { 
//  private void writeToFile(String data,Context context) { 
     Context context=getApplicationContext(); 
     View userText=(EditText) findViewById(R.id.userText); 
     String inputString=userText.toString(); 
      try { 
       OutputStreamWriter outputStreamWriter = new OutputStreamWriter(context.openFileOutput(FileName, Context.MODE_PRIVATE)); 
       outputStreamWriter.write(inputString); 
       outputStreamWriter.close(); 
      } 
      catch (IOException e) { 
       Log.e("Exception", "File write failed: " + e.toString()); 
      } 
     } 

} 

我不知道是否需要实现我的版本ArrayAdapter。我其实并没有完全理解它和它的参数是如何工作的。

Answer 1

变化

 String inputString=userText.toString(); 

到

 String inputString=userText.getText().toString();