Java 在我的自定义列表视图中，Android==>；空指针异常。。？

我不熟悉Android和Java， 请帮帮我，这让我疯狂了2天。 我的代码有什么问题

当我运行代码时，它显示“不幸的是（程序）已停止

我尝试在调试模式下查找。我看到空指针异常

问题是我不知道错误在哪里

---

MainActivity.Java

public class MainActivity extends Activity {

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

    ArrayList<Food> arrayList = new ArrayList<Food>();
    Food f1 = new Food("COKE", 1, 1, 1);
    Food f2 = new Food("PEPSI", 2, 2, 2);
    Food f3 = new Food("Pizza", 3, 3, 2);
    Food f4 = new Food("Sprite", 4, 4, 2);

    arrayList.add(f1);
    arrayList.add(f2);
    arrayList.add(f3);
    arrayList.add(f4);

    FoodAdapter fa = new FoodAdapter(this, R.layout.food_row, arrayList);
    ListView lv = (ListView) findViewById(R.id.listView1);
    lv.setAdapter(fa);

}

}

编辑：

日志跟踪

  04-20 00:47:56.785: W/ResourceType(1486): No package identifier when getting value for resource number 0x00000001
04-20 00:47:56.785: D/AndroidRuntime(1486): Shutting down VM
04-20 00:47:56.785: W/dalvikvm(1486): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
04-20 00:47:56.814: E/AndroidRuntime(1486): FATAL EXCEPTION: main
04-20 00:47:56.814: E/AndroidRuntime(1486): android.content.res.Resources$NotFoundException: String resource ID #0x1
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.content.res.Resources.getText(Resources.java:247)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.TextView.setText(TextView.java:3428)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at com.example.testconcept.FoodAdapter.getView(FoodAdapter.java:50)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.AbsListView.obtainView(AbsListView.java:2033)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.ListView.makeAndAddView(ListView.java:1772)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.ListView.fillDown(ListView.java:672)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.ListView.fillFromTop(ListView.java:732)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.ListView.layoutChildren(ListView.java:1625)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.AbsListView.onLayout(AbsListView.java:1863)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.View.layout(View.java:11180)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.View.layout(View.java:11180)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.LinearLayout.onLayout(LinearLayout.java:1399)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.View.layout(View.java:11180)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.View.layout(View.java:11180)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1468)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2418)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.os.Looper.loop(Looper.java:137)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at android.app.ActivityThread.main(ActivityThread.java:4340)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at java.lang.reflect.Method.invokeNative(Native Method)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at java.lang.reflect.Method.invoke(Method.java:511)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
04-20 00:47:56.814: E/AndroidRuntime(1486):     at dalvik.system.NativeStart.main(Native Method)

---

您还没有实例化您的持有者

if(convertView==null){

    holder =new FoodHolder();
     ..
     ..

}

编辑：

第二个问题是

您正在为GetView中的TextView分配int值，它会将其视为字符串资源id

所以它将抛出字符串资源未找到异常

试着把它们设置成这样

 holder.FoodId.setText(String.valueOf(food.FoodId));
 holder.Name.setText(food.Name);
 holder.SubId.setText(String.valueOf(food.SubId));

---

您还没有实例化您的持有者

if(convertView==null){

    holder =new FoodHolder();
     ..
     ..

}

编辑：

第二个问题是

您正在为GetView中的TextView分配int值，它会将其视为字符串资源id

所以它将抛出字符串资源未找到异常

试着把它们设置成这样

 holder.FoodId.setText(String.valueOf(food.FoodId));
 holder.Name.setText(food.Name);
 holder.SubId.setText(String.valueOf(food.SubId));

---

以这种方式初始化和使用它

ViewHolder holder;              
if (convertView == null) 
{
   holder = new ViewHolder();
   holder.text = (TextView) rowView.findViewById(R.id.list_text);                   
   rowView.setTag(holder);
} 
else
{
    rowView = convertView;
    holder = new ViewHolder();
    holder = (ViewHolder) rowView.getTag();
}   

---

以这种方式初始化和使用它

ViewHolder holder;              
if (convertView == null) 
{
   holder = new ViewHolder();
   holder.text = (TextView) rowView.findViewById(R.id.list_text);                   
   rowView.setTag(holder);
} 
else
{
    rowView = convertView;
    holder = new ViewHolder();
    holder = (ViewHolder) rowView.getTag();
}   

---

请编辑您的问题并包含崩溃的logcat输出。

objects

变量对于

ArrayAdapter

来说确实是不必要的。请编辑您的问题并包含崩溃的logcat输出。

objects

变量对于

ArrayAdapter

来说确实是不必要的。它不起作用。现在我需要它收到“未找到资源”。感谢您的快速回复@Pragnani@riseres“它不起作用“在这个意义上？这将导致异常，因为您的持有者为空。i、 在我编辑了我的答案后，在保持架前删除类型。如果日志不起作用，也发布日志。我在答案部分添加了catlog@Pragnani@riseres你试过我最新的编辑吗。。？不要将其作为新答案发布删除并编辑您的问题。@riseres我已经在编辑中发布了上述异常的答案，请检查..它不起作用。现在我得到了“找不到资源”。感谢您的快速回复@Pragnani@riseres从某种意义上说“它不起作用”？这将导致异常，因为您的持有者为空。i、 在我编辑了我的答案后，在保持架前删除类型。如果日志不起作用，也发布日志。我在答案部分添加了catlog@Pragnani@riseres你试过我最新的编辑吗。。？不要将其作为新答案发布删除并编辑您的问题。@riseres我已经在编辑中发布了上述异常的答案，请检查。。