如何在ListFragment中使用setEmptyView()和自定义列表布局

Question

我正在使用一些分页器Fragments.

我想在列表中没有条目时显示一条消息(Fragment).

我试图用Textview同android:id="@id/android:empty,但它不工作.

自定义列表布局代码:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="@dimen/padding_medium" >

    <TextView
        android:id="@+id/label_value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:layout_marginLeft="@dimen/padding_medium"
        android:text="@string/label_value"
        android:textColor="@android:color/white"
        android:textSize="18sp" />

    <TextView
        android:id="@+id/label_date"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:layout_marginRight="@dimen/padding_medium"
        android:text="@string/title_time"
        android:textColor="@android:color/white"
        android:textSize="16sp" />

</RelativeLayout>

列表适配器类:

public class JournalAdapter extends ArrayAdapter<String> {

    private final Context context;
    private final List<String> values;
    private final List<String> dates;

    public JournalAdapter(Context context, List<String> values,
            List<String> dates) {
        super(context, R.layout.layout_journal_list, values);

        this.context = context;
        this.values = values;
        this.dates = dates;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View rowView = inflater.inflate(R.layout.layout_journal_list, parent, false);

        TextView value = (TextView) rowView.findViewById(R.id.label_glucose);
        TextView date = (TextView) rowView.findViewById(R.id.label_date);

        value.setText(values.get(position));
        date.setText(dates.get(position));

        return rowView;
    }

}

列表解析方法:

private void initListView() {
        values = dataSource.getAllValues();

        List<String> values = new ArrayList<String>();
        List<String> dates = new ArrayList<String>();

        for (Value value : values) {
            values.add(Double.toString(value.getValue()));
            dates.add(secondsToDate(value.getDate()));
        }

        setListAdapter(new JournalAdapter(context, values, dates));

        listView = getListView();
        listView.setEmptyView(noItems("NO ITEMS"));
        listView.setOnItemClickListener(this);
    }

noItems 方法:

private TextView noItems(String text) {
        TextView emptyView = new TextView(context);
        emptyView.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
                LayoutParams.FILL_PARENT));
        emptyView.setText(text);
        emptyView.setTextColor(Color.WHITE);
        emptyView.setTextSize(20);
        emptyView.setVisibility(View.GONE);
        emptyView.setGravity(Gravity.CENTER_VERTICAL
                | Gravity.CENTER_HORIZONTAL);

        return emptyView;
    }

Answer 1

这对我有用(得到William Remacle提出的这个问题的解决方案).您可能错过的是将创建添加到布局父级(下面方法底部的第二行代码):TextViewListViewnoItems

在我ListFragment使用以下方法获取空视图的视图:

private TextView noItems(String text) {
    TextView emptyView = new TextView(getActivity());
    //Make sure you import android.widget.LinearLayout.LayoutParams;
    emptyView.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
            LayoutParams.MATCH_PARENT));
    //Instead of passing resource id here I passed resolved color 
    //That is, getResources().getColor((R.color.gray_dark))
    emptyView.setTextColor(getResources().getColor(R.color.gray_dark));
    emptyView.setText(text);
    emptyView.setTextSize(12);
    emptyView.setVisibility(View.GONE);
    emptyView.setGravity(Gravity.CENTER_VERTICAL
            | Gravity.CENTER_HORIZONTAL);

    //Add the view to the list view. This might be what you are missing
    ((ViewGroup) getListView().getParent()).addView(emptyView);

    return emptyView;
}

然后,在onStart()所述的方法ListFragment设定的空视图:

@Override
public void onStart() {
    super.onStart();
    getListView().setEmptyView(
            noItems(getResources().getString(R.string.widget_empty)));
}