Problem/bug with a listview

I just want to store a data in a listview then displaying it with a textview, i identified the problem, it's in fact this ligne:

data = date + " : " + y + "L/100KM\n"+ " " + value1 + "L "+ value2 + "KM\n";

Operations made: 1-if i delete the first or the second "\n" the listview indicates that there is not any datas to display. 2- if i let the two "\n" then the value1 and value2 are not displayed !

The oncreate function of the class that show the datas:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.histo);
    context = getApplicationContext();
    activity = this;
    final SharedPreferences preferences = PreferenceManager
            .getDefaultSharedPreferences(context);
    String fileName = getResources().getString(R.string.fileName);
    fileDir = "" + preferences.getString("login", "") + "."+ preferences.getString("marque", "") + ".";
    s = myIO.ReadFilePerLine(getApplicationContext(), fileDir + fileName);

    updatelv(this);
    ListView L = (ListView) findViewById(R.id.lv);
   开发者_Python百科 L.setTextFilterEnabled(true);

the code when tapping the calculate button in the main class:

 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    context = getApplicationContext();
    Toast.makeText(carburant.this, "Bienvenue!", Toast.LENGTH_LONG).show();
    data = "";


  final EditText vol;
  final EditText kil;
  final EditText cons;

  vol = (EditText) findViewById(R.id.volume2);
  kil= (EditText) findViewById(R.id.kilometrage2);
  cons= (EditText) findViewById(R.id.consom2);

 Button button = (Button) findViewById(R.id.button);

 button.setOnClickListener(new View.OnClickListener() {
     @Override
      public void onClick(View v) {
        String value1 = (((EditText) findViewById(R.id.volume2))
                .getText()).toString();
        String value2 = (((EditText) findViewById(R.id.kilometrage2)).getText())
                .toString();

  if (value1 .equalsIgnoreCase("") && value2.equalsIgnoreCase(""))
                      {
      Toast.makeText(carburant.this, "Veuillez vérifier les deux champs", Toast.LENGTH_SHORT).show();
                      }
  else{
                              float q1=Float.parseFloat(vol.getText().toString());
                              float q2=Float.parseFloat(kil.getText().toString());
                              float x=((q1 / q2)* 100);
                              String y= Float.toString(x);
                              cons.setText(y);

                              SimpleDateFormat format = new SimpleDateFormat("dd/MM/yyyy");
                              String date = format.format(new Date());
                              data = date + " : " + y + "L/100KM\n"+ " " + value1 + "L "+ value2 + "KM\n";

      if (data != "" ) {
          SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
       String fileName = getResources().getString(R.string.fileName);
       String fileDir = ""+ preferences.getString("login", "") + "."+ preferences.getString("marque", "") + ".";
       myIO.WriteSettings(context, fileDir + fileName, data);
       data = "";

The list_item XML:

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dp"
android:textSize="16sp" >

Histo.XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent" android:layout_weight="1"
    android:id="@+id/ViewHisto">
    <ListView android:id="@+id/lv" android:layout_width="fill_parent"
        android:layout_height="fill_parent" android:layout_weight="1" />
</LinearLayout>

Main.XML:

    <LinearLayout android:id="@+id/layoutPrincipal"
   android:layout_width="fill_parent" android:layout_height="fill_parent"
   android:orientation="vertical"
   xmlns:android="http://schemas.android.com/apk/res/android">

   <TextView android:id="@+id/volume1" android:layout_width="wrap_content"
   android:layout_height="wrap_content" android:text="Volume(en Litres):">
   </TextView>
   <EditText android:id="@+id/volume2" android:layout_width="fill_parent"
      android:layout_height="wrap_content" android:textSize="18sp"
      android:numeric="integer|decimal"
      android:hint="@string/vol"
      >

   </EditText>




   <TextView android:id="@+id/kilometrage1" android:layout_width="wrap_content"
   android:layout_height="wrap_content" android:text="Kilometrage(en Kilomètres) :">
   </TextView>

   <EditText android:id="@+id/kilometrage2" android:layout_width="fill_parent"
      android:layout_height="wrap_content" android:textSize="18sp"
      android:numeric="integer|decimal"
      android:hint="@string/kil">

   </EditText>




   <TextView android:id="@+id/consom1" android:layout_width="wrap_content"
   android:layout_height="wrap_content" android:text="Consommation moyenne(en Litres/100KM) :">
   </TextView>
   <EditText android:id="@+id/consom2" android:layout_width="fill_parent"
      android:layout_height="wrap_content" android:textSize="18sp"
      android:numeric="integer|decimal"
      android:hint="@string/cons">
   </EditText> 


  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">
<Button
    android:text="Calculer" 
    android:id="@+id/button" 
    android:layout_height="wrap_content"
    android:layout_width="wrap_content">
</Button>
<Button
    android:text="Reset" 
    android:id="@+id/button2" 
    android:layout_marginLeft="280px"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content" >
 </Button>
</LinearLayout>
</LinearLayout>

</LinearLayout>

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Did you consider creating a View to through an Adapter containing two TextViews to you display it correctly? It's the best approach.