的Android的ListView自定義適配器基礎知識：getView（）的位置始終爲0

Question

GetView位置始終爲0。繼http://www.codelearn.org/android-tutorial/android-listview所示的基本概念，我的代碼如下：

public void DisplayUserList() 
{ // Get data list from SQL Database 
    UserList = mySQLiteHelper.getUserList(ACTIVE); 

    // Get ListView 
    user_listview_control = (ListView) findViewById(R.id.user_listview); 

    // Get Adapter 
    userAdapter = new UserAdapter(); 

    // Bind it all together 
    user_listview_control.setAdapter(userAdapter); 

} // end DisplayUserList() 

// User List Base Adapter 
public class UserAdapter extends BaseAdapter { 

    @Override 
    public int getCount() { 

     return UserList.size(); 
    } 

    @Override 
    public Structures.user_struct getItem(int arg0){ 
     return UserList.get(arg0); 
    } 

    @Override 
    public long getItemId(int arg0){return arg0;} 

    @Override 
    public View getView(int position, View arg1, ViewGroup arg2){ 
     if (arg1 == null){ 
      LayoutInflater inflater = (LayoutInflater) Settings.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      try { 
       arg1 = inflater.inflate(R.layout.userlist_item, arg2, false); 
      } 
      catch (Exception ex){ 
       String errorMessage = ex.getMessage(); 
      } 
     } 

     TextView username = (TextView)arg1.findViewById(R.id.username); 
     TextView firstname = (TextView)arg1.findViewById(R.id.userfirstname); 
     TextView lastname = (TextView)arg1.findViewById(R.id.userlastname); 
     TextView lastlogin = (TextView)arg1.findViewById(R.id.userlastlogin); 

     UserData = UserList.get(position); //(always zero) 

     username.setText(user.username); 
     firstname.setText(user.user_firstname); 
     lastname.setText(user.user_lastname); 

     if (user.user_lastlogin_date.length() == 0) { 
      lastlogin.setText("--"); 
     } else { 
      lastlogin.setText(user.user_lastlogin_date); 
     } 

     // OnClickListener for this row. 
     arg1.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       Toast.makeText(Settings.this, "User Clicked", Toast.LENGTH_SHORT).show(); 
       //Integer position = (Integer) view.getTag(); 
      } 
     }); 

     return arg1; 
    } 
} // end UserAdapter() 

SQLite的數據表有三個要素：在的UserList返回定義爲：

public List<Structures.user_struct> UserList; 

當user_listview_control.setAdapter被調用時，getCount將（）被調用多次只是getView之前（返回值3）（）被調用。在getView（）中，位置始終爲0.生成的ListView顯示僅與數據庫的第一項有關。 [注：如果我強制position = 1或2，則代碼返回該列表中的下一個用戶]。我沒有看到我離開的地方。它可能是限制顯示的xml佈局嗎？當我運行上述引用的示例代碼時，它確實可以用作簡單的xml佈局。所以？？？

Answer 1

GetUserList：

public List<Structures.user_struct> getUserList(int isActive) { 
    // Get List of Users in database 
    // Filter isActive 0 = Not, 1 = Is, 2 = ALL 
    // NOte: Is userList database does not exist, create it. 

    Structures.user_struct UserData = new Structures.user_struct(); 
    List<Structures.user_struct> UserList = new  ArrayList<Structures.user_struct>(); 

    SQLiteDatabase db = this.getReadableDatabase(); 
    String strSQL = "select * from " + Structures.USER_TABLE_NAME ; 
    if (isActive < 2){  // filter is or is not active Only 
     strSQL += " where " + Structures.USER_COL_IS_ACTIVE + "=" + isActive; 
    } 

    Cursor cursor = db.rawQuery(strSQL, null); 
    cursor.moveToFirst(); 
    while (cursor.isAfterLast() == false) { 

     UserData.user_id = cursor.getInt(cursor.getColumnIndex(Structures.USER_COL_ID)); 
     UserData.user_is_active = cursor.getInt(cursor.getColumnIndex(Structures.USER_COL_IS_ACTIVE)); 
     UserData.username = cursor.getString(cursor.getColumnIndex(Structures.USER_COL_USERNAME)); 
     UserData.user_password = cursor.getString(cursor.getColumnIndex(Structures.USER_COL_PASSWORD)); 
     UserData.user_firstname = cursor.getString(cursor.getColumnIndex(Structures.USER_COL_FIRSTNAME)); 
     UserData.user_lastname = cursor.getString(cursor.getColumnIndex(Structures.USER_COL_LASTNAME)); 
     UserData.user_date_created = cursor.getString(cursor.getColumnIndex(Structures.USER_COL_DATECREATED)); 
     UserData.user_date_updated = cursor.getString(cursor.getColumnIndex(Structures.USER_COL_DATEUPDATED)); 
     UserData.user_lastlogin_date = cursor.getString(cursor.getColumnIndex(Structures.USER_COL_DATELASTLOGIN)); 

     // Copy UserData to ArrayList of structures 
     UserList.add(UserData); 

     cursor.moveToNext(); 

     UserData = new Structures.user_struct(); 
    } 

    return UserList; 
} // end getUserList() 

的UserData

// User Data Structure 
public static class user_struct { 
    public int user_id; 
    public int user_is_active;  // 0=not, 1=is 
    public String username; 
    public String user_password; 
    public String user_firstname; 
    public String user_lastname; 
    public int user_permission_level_id; 
    public String user_date_created; 
    public String user_date_updated; 
    public String user_lastlogin_date; 
} // end user_structure() 

userlist_item.xml：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:orientation="vertical" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content"> 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="horizontal" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"> 

    <TextView android:id="@+id/username" 
     android:layout_width="@dimen/user_list_width" 
     android:layout_height="wrap_content" 
     style="@style/User_List" 
     android:text="username"/> 

    <Space 
     android:layout_width="5dp" 
     android:layout_height="wrap_content" /> 

    <TextView android:id="@+id/userfirstname" 
     android:layout_width="@dimen/user_list_width" 
     android:layout_height="wrap_content" 
     style="@style/User_List" 
     android:text="first name"/> 

    <Space 
     android:layout_width="5dp" 
     android:layout_height="wrap_content" /> 

    <TextView android:id="@+id/userlastname" 
     android:layout_width="@dimen/user_list_width" 
     android:layout_height="wrap_content" 
     style="@style/User_List" 
     android:text="last name"/> 

    <Space 
     android:layout_width="5dp" 
     android:layout_height="wrap_content" /> 

    <TextView android:id="@+id/userlastlogin" 
     android:layout_width="@dimen/user_list_width" 
     android:layout_height="wrap_content" 
     style="@style/User_List" 
     android:text="last login"/> 

</LinearLayout>