从Firebase获取值到ListView

Question

我需要从“出勤”节点填充列表视图：

每个列表项应显示运动，日期和时间。以下是我正在做的事情：

        final DatabaseReference attendanceRef = database.getReference()
            .child(Constants.MEMBERS_NODE).child(userID).child("attendance").child(today);

    attendanceRef.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {

            for(DataSnapshot snapshot : dataSnapshot.getChildren()){
                String sport = snapshot.getKey();
                String date = (String) snapshot.child("date").getValue();
                String timeStamp = (String) snapshot.child("timestamp").getValue();

            }
        }

请注意，我不能只获取快照的值，因为我需要获取密钥，这是运动名称。我不确定如何处理它。感谢您的任何建议

Answer 1

创建一个hashmap来映射值。

HashMap<String,String> sportsMap = snapshot.getValue();
String date = sportsMap.get("date");

Answer 2

我希望列表项显示体育名称及其参加的时间和日期。答案并不复杂，但需要深入了解。

我应该创建一个模型类来获取日期和时间戳：

public class MemberAttendance {

private String sport;
private long timestamp;

public MemberAttendance() {

}

public MemberAttendance(String sport, long timestamp) {
    this.sport = sport;
    this.timestamp = timestamp;
}

public String getSport() {
    return sport;
}

public long getTimestamp() {
    return timestamp;
}

public void setSport(String sport) {
    this.sport = sport;
}

public void setTimestamp(long timestamp) {
    this.timestamp = timestamp;
}

}

然后像以前一样创建一个引用：

final DatabaseReference attendanceRef = database.getReference()
            .child(Constants.MEMBERS_NODE).child(userID).child("attendance").child(today);

然后像这样初始化适配器：

        attendanceAdapter = new MemberAttendanceAdapter(getActivity(), MemberAttendance.class,
            R.layout.list_item_attendance, attendanceRef);

    attendanceListView.setAdapter(attendanceAdapter);

真正的诀窍在于我需要让运动等于参考键，这是运动名称：

public class MemberAttendanceAdapter extends FirebaseListAdapter<MemberAttendance> {

public MemberAttendanceAdapter(Activity activity, Class<MemberAttendance> modelClass, int modelLayout, Query ref) {
    super(activity, modelClass, modelLayout, ref);
}

@Override
protected void populateView(View view, MemberAttendance memberAttendance, int i) {

    String sport = getRef(i).getKey();

    // Create views and assign values
    TextView sportTxtView = (TextView) view.findViewById(R.id.sportTxtView);
    sportTxtView.setText(sport);

    // This time stamp can return date and time, so there is no need to create a date getter
    Date timestamp = new Date(memberAttendance.getTimestamp());

    TextView dayTxtView = (TextView) view.findViewById(R.id.dayTxtView);
    dayTxtView.setText(new SimpleDateFormat("dd-MM-yyyy").format(timestamp));

    // Show the time
    TextView dateTxtView = (TextView) view.findViewById(R.id.dateTxtView);
    dateTxtView.setText(new SimpleDateFormat("hh:mm a").format(timestamp));

}

}