Question

我有一个任务是使用这个名为todo_item.xml的类的相对布局为对象扩展一个名为“ToDoItem”的类。我刚开始学习android编程，我无法弄清楚为什么我得到了跟随错误。

    java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference

我的代码看起来像这样，有更多类特定的函数，但我已经跳过它们以使问题代码更加可见。

    public class ToDoListAdapter extends BaseAdapter {

private final List<ToDoItem> mItems = new ArrayList<ToDoItem>();
private final Context mContext;
LayoutInflater mInflater;

private static final String TAG = "Lab-UserInterface";

public ToDoListAdapter(Context context) {

    mContext = context;
    mInflater = LayoutInflater.from(context);


}// Create a View for the ToDoItem at specified position
// Remember to check whether convertView holds an already allocated View
// before created a new View.
// Consider using the ViewHolder pattern to make scrolling more efficient
// See: http://developer.android.com/training/improving-layouts/smooth-    scrolling.html

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

    // TODO - Get the current ToDoItem
    final ToDoItem toDoItem = (ToDoItem) getItem(position);


    // TODO - Inflate the View for this ToDoItem
    // from todo_item.xml


    convertView = mInflater.inflate(R.layout.todo_item,parent,false);

    RelativeLayout itemLayout = (RelativeLayout) convertView.findViewById(R.id.RelativeLayout1);

    // Fill in specific ToDoItem data
    // Remember that the data that goes in this View
    // corresponds to the user interface elements defined
    // in the layout file

    // TODO - Display Title in TextView
    final TextView titleView = new TextView(null);
    titleView.setText(toDoItem.getTitle());

Answer 1

在你的getView中试试这个

convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.todo_item, parent, false);

无需mInflater = LayoutInflater.from(context)

调用虚方法Context.getResource（）时出现Android NullPointerException

1 个答案: