錯誤：未指定資源類型（'id'，值爲'@android：id = list'）

Question

錯誤的含義是什麼？

package conde.app; 

import android.app.Activity; 
import android.os.Bundle; 
import android.widget.*; 
import android.app.*; 
import android.view.*; 
import android.util.*; 
import android.database.sqlite.*; 
import android.content.*; 
import java.util.*; 
import android.database.*; 
import android.R.*; 

public class MKBApplication extends Activity 
{ 
    /** Called when the activity is first created. */ 

    Button aBtn = (Button) findViewById(R.id.addBtn); 
    Button dBtn = (Button) findViewById(R.id.deleteBtn); 
    private GroceryDataSource datasource; 

    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     datasource = new GroceryDataSource(this); 
     datasource.open(); 
     List<Grocery> values = datasource.getAllGroceryItems(); 
     ArrayAdapter<Grocery> adapter = new ArrayAdapter<Grocery>(this, 
      android.R.layout.simple_list_item_2, values); 
     setListAdapter(adapter); 
    } 

    public void onClick(View view) { 
     @SuppressWarnings("unchecked") 
     ArrayAdapter<Grocery> adapter = (ArrayAdapter<Grocery>) getListAdapter(); 
     Grocery grocery = null; 
     switch(view.getId()){ 
      case R.id.addBtn: 
       String[] name = new String[] { "Pork", "Chicken", "Onion" }; 
       String[] quantity = new String[] { "1/2 kilo", "3 kilos", "1 kilo" }; 
       int nextInt = new Random().nextInt(3); 
       grocery = datasource.createGroceryItem(name[nextInt], quantity[nextInt]); 
       adapter.add(grocery); 
      break; 
      case R.id.deleteBtn: 
       if (getListAdapter().getCount() > 0) { 
        grocery = (Grocery) getListAdapter().getItem(0); 
        datasource.deleteGroceryItem(grocery); 
        adapter.remove(grocery); 
       } 
      break; 
     } 
     adapter.notifyDataSetChanged(); 
    } 

    @Override 
    protected void onResume() { 
     datasource.open(); 
     super.onResume(); 
    } 

    @Override 
    protected void onPause() { 
     datasource.close(); 
     super.onPause(); 
    } 
} 

這裏是我的xml文件：

<?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" 
    > 
<TextView 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="Hello World, MKBApplication" 
    /> 
<Button 
    android:id="@+id/addBtn" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="ADD" 
/> 
<Button 
    android:id="@+id/deleteBtn" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="DELETE" 
/> 

<ListView 
    android:id="@android:id=list" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
/> 

</LinearLayout> 

Answer 1

<ListView 
    android:id="@android:id=list" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
/> 

應該

<ListView 
    android:id="@+id/list" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
/>