android - 删除 ArrayList 上的元素会在 ArrayAdapter 上抛出 IndexOutOfBoundsException

Question

我正在开发 Android 3.1 应用程序。

我有我的自定义 ArrayAdapter。我想在 ListView 中显示姓名列表。

这些名称是可以下载并保存在本地的表格。当用户下载并保存一个或多个时，我调用 updateFormsNotDownloaded()。但是当我这样做时，我得到了一个 IndexOutOfBoundsException。我认为这个问题是因为我调用了 notifyDataSetChanged()。

看看我的代码:

public class FormAdapter extends ArrayAdapter<Form>
{
    private Context context;
    private int layoutResourceId;
    private List<Form> forms;
    private ArrayList<Integer> checkedItemsPosition;
    private Button downloadButton;

    public ArrayList<Integer> getCheckedItemsPosition()
    {
        return checkedItemsPosition;
    }

    public String[] getSelectedFormsId()
    {
        String[] ids = new String[checkedItemsPosition.size()];
        int i = 0;
        for(Integer pos : checkedItemsPosition)
        {
            Form f = forms.get(pos.intValue());
            ids[i] = f.FormId;
            i++;
        }
        return ids;
    }

    /**
     * Called when selected forms has been downloaded and save it locally correctly.
     */
    public void updateFormsNotDownloaded()
    {
        ArrayList<Form> copyForms = new ArrayList<Form>();
        for (int i = 0; i < forms.size(); i++)
        {
            if (!checkedItemsPosition.contains(new Integer(i)))
                copyForms.add(forms.get(i));
        }
        forms = copyForms;
        checkedItemsPosition.clear();
        notifyDataSetChanged();
    }

    public FormAdapter(Context context, int textViewResourceId,
            List<Form> objects, Button downloadButton)
    {
        super(context, textViewResourceId, objects);

        this.context = context;
        this.layoutResourceId = textViewResourceId;
        this.forms = objects;
        this.checkedItemsPosition = new ArrayList<Integer>();
        this.downloadButton = downloadButton;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent)
    {
        View row = convertView;
        if (row == null)
        {
            LayoutInflater inflater = ((Activity)context).getLayoutInflater();
            row = inflater.inflate(layoutResourceId, parent, false);
        }

        Form f = forms.get(position);
        if (f != null)
        {
            CheckBox checkBox = (CheckBox)row.findViewById(R.id.itemCheckBox);
            if (checkBox != null)
            {
                checkBox.setText(f.Name);
                checkBox.setOnCheckedChangeListener(new OnCheckedChangeListener()
                {
                    public void onCheckedChanged(CompoundButton buttonView,
                            boolean isChecked)
                    {
                        //Form f = forms.get(position);
                        if (isChecked)
                        {
                            //checkedItems.add(f.FormId);
                            checkedItemsPosition.add(new Integer(position));
                        }
                        else
                        {
                            //checkedItems.remove(checkedItems.indexOf(f.FormId));
                            checkedItemsPosition.remove(checkedItemsPosition.indexOf(new Integer(position)));
                        }
                        downloadButton.setEnabled(checkedItemsPosition.size() > 0);
                    }
                });
            }
        }

        return row;
    }
}

我在表单上有三项，但我删除了其中一项。

为什么我会收到该异常？

这是异常日志:

java.lang.IndexOutOfBoundsException: Invalid index 2, size is 2
at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at es.viacognita.adapters.FormAdapter.getView(FormAdapter.java:89)
at android.widget.AbsListView.obtainView(AbsListView.java:1949)
at android.widget.ListView.makeAndAddView(ListView.java:1756)
at android.widget.ListView.fillDown(ListView.java:656)
at android.widget.ListView.fillSpecific(ListView.java:1314)
at android.widget.ListView.layoutChildren(ListView.java:1587)
at android.widget.AbsListView.onLayout(AbsListView.java:1800)
at android.view.View.layout(View.java:9581)
at android.view.ViewGroup.layout(ViewGroup.java:3877)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1542)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1403)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1314)
at android.view.View.layout(View.java:9581)
at android.view.ViewGroup.layout(ViewGroup.java:3877)
at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
at android.view.View.layout(View.java:9581)
at android.view.ViewGroup.layout(ViewGroup.java:3877)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1542)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1403)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1314)
at android.view.View.layout(View.java:9581)
at android.view.ViewGroup.layout(ViewGroup.java:3877)
at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
at android.view.View.layout(View.java:9581)
at android.view.ViewGroup.layout(ViewGroup.java:3877)
at android.view.ViewRoot.performTraversals(ViewRoot.java:1253)
at android.view.ViewRoot.handleMessage(ViewRoot.java:2003)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4025)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)

Answer 1

覆盖 getCount()。并返回其中的值 forms.size()。