Question

我在Android应用中有一个POJO列表，我目前正在listview / listitem中显示其中一个字段，如下所示：

List<NotificationItem> notifItems;
// snip, populate

ArrayAdapter adapter = new ArrayAdapter<>(this, R.layout.notification_item, notifItems);

ListView listView = (ListView) findViewById(R.id.notification_listview);
listView.setAdapter(adapter);

我的理解是listivew或者适配器使用POJO的toString，这是

public String toString() {
    SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd hh:mm");
    return _notificationTitle + " | " + dateFormatter.format(_notificationReceivedDate);
}

R.id.notificationitem是

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/label"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dip"
android:textSize="16sp"
android:textStyle="bold"></TextView>

到目前为止一切顺利，但我想要做的是在notificationitem布局文件中添加元素，然后更新Java代码以填充新字段。

这是怎么做到的？我不太了解适配器如何知道/将toString值放入notificationitem中的一个字段中。

Answer 1

public class NotificationItem {
    //your fields here
}
//-----------------------
public class NotifAdapter extends BaseAdapter {

    Context context;
    List<NotificationItem> data;

    public NotifAdapter(Context context, List<NotificationItem> data) {
        this.context = context;
        this.data = data;
    }

    @Override
    public int getCount() {
        return data.size();
    }

    @Override
    public Object getItem(int position) {
        return data.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = layoutInflater.inflate(R.layout.your_row_layout,parent, null);
        TextView tx = convertView.findViewById(R.id.your_widget_inside_row_layout);
        tx.setText(data.yourDataPropery);
        return convertView;
    }
}
// In your activity
NotifAdapter adapter = new NotifAdapter(this, ArrayList<NotificationItem>);
listView.setAdapter(adapter);

在listview中显示POJO对象的多个字段

1 个答案: