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我想从列表视图和数据库中删除选定的项目。我为列表视图和数据库插入编写了代码。

但问题是删除我正在使用 OnItemClick 侦听器删除特定项目。

对于删除项目，我将 Position 变量传递给数据库删除方法。它可以工作，但是当您删除列表的上部项目而不是尝试删除下部项目时，它不会删除。

可能是因为我将位置变量传递给数据库删除方法。在数据库中我用主键 ID 检查它，并且在删除上项后下项的 ID 没有改变，所以会出现这个问题

建议我一些好的解决方案

这是代码片段代码

 public void onStart() {
   super.onStart();
   initfrag();}
private void initfrag() {
// TODO Auto-generated method stub
    dh = new com.myapp.database.DatabaseHelper(getActivity());
    nameArray   =   new  ArrayList<String>();
    db = new com.myapp.database.DatabaseHelper(getActivity());
    list = (ListView)getView().findViewById(R.id.fevlist);
    adapter=new ListAdapter(getActivity(), nameArray);
    Log.d("Reading: ", "Reading all contacts..");
     List<Fevorites> contacts = db.getAllContacts();     
     for (Fevorites cn : contacts) {
         s = "Name: " + cn.getID() + " ,Phone: " + cn.getPhoneNumber()+"\n";
         nameArray.add(s);
         list.setAdapter(adapter);     
             }
    list.setAdapter(adapter);
      list.setOnItemClickListener(new OnItemClickListener() {
          public void onItemClick(AdapterView adapterView, View view, int position, long id) {
        // TODO Auto-generated method stu   
         nameArray.remove(position);
         Toast t = Toast.makeText(getActivity(), nameArray.get(position), Toast.LENGTH_SHORT);
         t.show();
        // dh.Deleteitem();
            adapter.notifyDataSetChanged();
            adapter=new ListAdapter(getActivity(), nameArray);
         list.setAdapter(adapter);

    }
}); 
}

这里是Fevorites

public class Fevorites {
//private variables
int _id;
String _name;
String _phone_number;
// Empty constructor
public Fevorites(){
}
// constructor
public Fevorites(int id, String name, String _phone_number){
    this._id = id;
    this._name = name;
    this._phone_number = _phone_number;
}
// constructor
public Fevorites(String name, String _phone_number){
    this._name = name;
    this._phone_number = _phone_number;
}
// getting ID
public int getID(){
    return this._id;
}
// setting id
public void setID(int id){
    this._id = id;
}
// getting name
public String getName(){
    return this._name;
}
// setting name
public void setName(String name){
    this._name = name;
}

// getting phone number
public String getPhoneNumber(){
    return this._phone_number;
}

// setting phone number
public void setPhoneNumber(String phone_number){
    this._phone_number = phone_number;
}

}

数据库助手类

public DatabaseHelper(Context context) {
    super(context,DATABASE_NAME , null,DATABASE_VERSION);
    // TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub

    String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
            + KEY_ID + " INTEGER PRIMARY KEY," + KEY_ARTIST + " TEXT,"
            + KEY_SONG + " TEXT" + ")";
    db.execSQL(CREATE_CONTACTS_TABLE);
}
public void addContact( ) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_ARTIST, "XYZ  "); // Contact Name
    values.put(KEY_SONG, "XYZ testing "); // Contact Phone
    // Inserting Row
    db.insert(TABLE_CONTACTS, null, values);
    db.close(); // Closing database connection
}
public void Deleteitem(String string)
        {
    SQLiteDatabase db = this.getWritableDatabase();
    String query = "DELETE FROM favorite WHERE id="+string;
    db.execSQL(query);
        }
 // Getting All Contacts
public List<Fevorites> getAllContacts() {
    List<Fevorites> contactList = new ArrayList<Fevorites>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_CONTACTS;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            Fevorites contact = new Fevorites();
            contact.setID(Integer.parseInt(cursor.getString(0)));
            contact.setName(cursor.getString(1));
            contact.setPhoneNumber(cursor.getString(2));
            // Adding contact to list
            contactList.add(contact);
        } while (cursor.moveToNext());
    }
    // return contact list
    return contactList;
}
Fevorites getContact(int id) {
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
            KEY_SONG, KEY_ARTIST }, KEY_ID + "=?",
            new String[] { String.valueOf(id) }, null, null, null, null);
    if (cursor != null)
        cursor.moveToFirst();
    Fevorites contact = new Fevorites(Integer.parseInt(cursor.getString(0)),
            cursor.getString(1), cursor.getString(2));
    // return contact
    return contact;
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub
}

这是自定义列表适配器类

*列出适配器类 *

public class ListAdapter extends BaseAdapter {
private Activity activity;
private ArrayList<String> name;
private static LayoutInflater inflater=null;

public ListAdapter(Activity a, ArrayList<String> nameArray) {
    activity = a;
    name    =   nameArray;
    inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public int getCount() {
    return name.size();
}
public Object getItem(int position) {
    return position;
}
public long getItemId(int position) {
    return position;
}
public static class ViewHolder{
    public TextView text;
}
public View getView(int position, View convertView, ViewGroup parent) {
    View vi=convertView;
    ViewHolder holder;
    if(convertView==null){
        vi = inflater.inflate(R.layout.fevorites_list, null);
        holder=new ViewHolder();
        holder.text=(TextView)vi.findViewById(R.id.list_item_entry_title);
        vi.setTag(holder);
    }
    else
        holder=(ViewHolder)vi.getTag();
    holder.text.setText(name.get(position));
    return vi;
}

}

4

1 回答 1

2

通常，您检索List某种对象（假设在您的情况下：收藏夹列表），然后将其传递给您adapter以在 a 中显示它ListView。所以你CustomAdapter会是这样的：

public class ListAdapter extends BaseAdapter {
private Context context;
private ArrayList<Favorites> items;
private LayoutInflater inflater=null;

public ListAdapter(Context context, ArrayList<Favorites> items) {
    this.context = context;
    this.items   =   items;
    inflater = LayoutInflater.from(context);
}
public int getCount() {
    return items.size();
}
public Favorites getItem(int position) {
    return items.get(position);
}
public long getItemId(int position) {
    return items.get(position).getId();
}
public static class ViewHolder{
    public TextView text;
}
public View getView(int position, View convertView, ViewGroup parent) {
    View vi=convertView;
    ViewHolder holder;
    if(convertView==null){
        vi = inflater.inflate(R.layout.fevorites_list, parent, false);
        holder=new ViewHolder();
        holder.text=(TextView)vi.findViewById(R.id.list_item_entry_title);
        vi.setTag(holder);
    }
    else 
         holder=(ViewHolder)vi.getTag();

    holder.text.setText(items.get(position).getName());
    return vi;


   }
 }

然后，实例化适配器并将其传递给您的 listView，如下所示：

//retreive the list of contacts
List<Fevorites> contacts = db.getAllContacts(); 
ListAdapter adapter = new ListAdapter(ActivityName.this , contacts);
list.setAdapter(adapter);

注意：用ActivityName您的活动名称替换

于 2012-11-12T13:30:48.753 回答