检查ListView是否为空

Question

我正在使用SQLITE来存储，检索和删除购物车中添加的值。并为自定义列表视图中的每一行添加一个删除按钮。

所以当用户点击特定行上的删除按钮时，它也会删除表中的数据。

我的问题是，当用户删除购物车中的所有东西时，我将如何检查listview是否为空？

有人可以指点我该做什么或使用什么？提前致谢！ ：d

这是我的车类：

//CART LISTVIEW 
private ArrayList<String> orderid; 
private ArrayList<String> orderName; 
private ArrayList<String> orderSize; 
private ArrayList<String> orderQuantity; 

private cartDatabaseHelper db; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_cart); 

    db = new cartDatabaseHelper(this); 

    //CART LISTVIEW 
    orderid = new ArrayList<>(); 
    orderName = new ArrayList<>(); 
    orderSize = new ArrayList<>(); 
    orderQuantity = new ArrayList<>(); 

    TextView textEmpty = (TextView) findViewById(R.id.textEmpty); 

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

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

    //ListView listView1 = (ListView) findViewById(R.id.emptyView); 


    final ListCartAdapter adapter = new ListCartAdapter(cart.this, orderid, orderName, orderSize, orderQuantity); 
    listView.setAdapter(adapter); 


    Cursor data = db.getListContents(); 
    data.moveToFirst(); 

    if(data.getCount() == 0){ 
     textEmpty.setVisibility(View.VISIBLE); 
     btnCheckout.setVisibility(View.GONE); 
    } 
    else 
    { 
     textEmpty.setVisibility(View.GONE); 
     btnCheckout.setVisibility(View.VISIBLE); 

     data.moveToFirst(); 
     do{ 
      orderid.add(data.getString(0)); 
      orderName.add(data.getString(1)); 
      orderSize.add(data.getString(2)); 
      orderQuantity.add(data.getString(3)); 
     } while (data.moveToNext()); 

    } 
    data.close(); 
} 


@Override 
public void onBackPressed() { 
    finish(); 
} 

，这是我的适配器类别：

public class ListCartAdapter extends BaseAdapter { 


private Context context; 

private ArrayList<String> orderid; 
private ArrayList<String> orderName; 
private ArrayList<String> orderSize; 
private ArrayList<String> orderQuantity; 

public ListCartAdapter(Context context, ArrayList<String> orderid, ArrayList<String> orderName, ArrayList<String> orderSize, ArrayList<String> orderQuantity){ 
    this.context = context; 
    this.orderid = orderid; 
    this.orderName = orderName; 
    this.orderSize = orderSize; 
    this.orderQuantity = orderQuantity; 

} 

@Override 
public int getCount() { 
    return orderName.size(); 
} 

@Override 
public Object getItem(int position) { 
    return orderName.get(position); 
} 

@Override 
public long getItemId(int position) { 
    return 0; 
} 


@Override 
public View getView(final int position, View convertView, ViewGroup parent) { 

    final View listView; 
    final LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    listView = inflater.inflate(R.layout.cart_list_item, null); 

    TextView number = (TextView) listView.findViewById(R.id.textID); 
    TextView name = (TextView) listView.findViewById(R.id.textOrderName); 
    TextView size = (TextView) listView.findViewById(R.id.textOrderSize); 
    TextView quantity = (TextView) listView.findViewById(R.id.textOrderQuantity); 

    ImageButton btnRemove = (ImageButton) listView.findViewById(R.id.btnRemove); 

    number.setText(orderid.get(position)); 
    name.setText(orderName.get(position)); 
    size.setText(orderSize.get(position)); 
    quantity.setText(orderQuantity.get(position)); 

    final cartDatabaseHelper db = new cartDatabaseHelper(context); 


    //BUTTON TO REMOVE ROW 
    btnRemove.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(final View v) { 

      new AlertDialog.Builder(context) 
        .setTitle("REMOVE" + " " + orderName.get(position) + " " + "FROM CART?") 
        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() { 
         public void onClick(DialogInterface dialog, int which) { 

           db.removeSingleContact(orderid.get(position)); 

           orderName.remove(position); 
           orderSize.remove(position); 
           orderQuantity.remove(position); 
           notifyDataSetChanged(); 
         } 
        }) 
        .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() { 
         public void onClick(DialogInterface dialog, int which) { 

          dialog.dismiss(); 
         } 
        }) 
        .show(); 
     } 
    }); 
    return listView; 
} 

Answer 1

嗨我解决我的问题，我只加EmptyView。所以，当列表视图变空，它会自动显示这样

ListCartAdapter adapter = new ListCartAdapter(cart.this, orderid, orderName, orderSize, orderQuantity); 
    listView.setAdapter(adapter); 
listView.setEmptyView(findViewById(R.id.emptyView)); 

感谢大家，帮助一个emptyview：d

Answer 2

只是检查是否adapter.getCount() == 0

Answer 3

只是检查是否(cartlist.size()<0)那么你的列表是空的。！

Answer 4

您可以使用下面做同样的

listView.getAdapter().getItemCount(); 

要合并这一点，你需要使听者删除的项目，并在您的活动实现。然后在该覆盖方法中，您可以使用上面的代码。

Answer 5

如果检查adapter.isEmpty（）如果返回真列表是空的，如果它返回假那么它是不是空