Question

我想存储所有出生日期并与当前日期相匹配。

我得到了所有出生日期，但是当我想要匹配时，我会遇到时间和日期格式错误。

LoadData();
ArrayList<User> arrayList = new ArrayList<>();
String CurrentData = GetCurrentData();
String BirthdayData = GetBirthdayData(arrayList);


Log.e("String", CurrentData + "  " + BirthdayData);

if (CurrentData.equals(BirthdayData)) {
    localData.set_hour(0);
    localData.set_min(0);
    NotificationScheduler.setReminder(NavDrawerActivity.this, 
    AlarmReceiver.class, localData.get_hour(), localData.get_min());
} else {

}

此方法用于获取所有出生日期：

public String GetBirthdayData(ArrayList<User> bdayList)
{
    String birthday = " ";
    for (int i=0;i<bdayList.size();i++)
    {
        User user=bdayList.get(i);
        birthday =user.getBday();
    }
    Log.e("GetBirthdayData1212", birthday);

    User user=new User();
    String birthday = user.getBday();


    SimpleDateFormat dateFormat = new SimpleDateFormat("d/M/yyyy");
    Date myDate = null;
    try {
        myDate = dateFormat.parse(birthday);
        Log.e("myDate", birthday);
    } catch (ParseException e) {
        e.printStackTrace();
    }

    SimpleDateFormat timeFormat = new SimpleDateFormat("d/M");
    String birthdayData = timeFormat.format(myDate);
    return birthdayData.toString();
}

此方法获取当前日期：

    public String GetCurrentData() {
    //get current Date
    DateFormat dayf = new SimpleDateFormat("d/M");
    String currentDate = dayf.format(new Date());
    return currentDate;
}

此方法用于获取所有数据并存储在ArrayList：

中

 public void LoadData() {
    mDatabaseReference = 
    FirebaseDatabase.getInstance().getReference("users");
    mDatabaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            BdayList = new ArrayList<User>();
            for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                User value = dataSnapshot1.getValue(User.class);
                User fire = new User();
                String bday = value.getBday();
                fire.setBday(bday);
                BdayList.add(fire);
                GetBirthdayData(BdayList);
                Log.e("BdayList", BdayList.toString());

            }

        }

        @Override
        public void onCancelled(DatabaseError error) {
            // Failed to read value
            Log.w("Hello", "Failed to read value.", error.toException());
        }
    });
}

logcat的：

  Caused by: java.lang.NullPointerException: Attempt to invoke virtual 
method 'long java.util.Date.getTime()' on a null object reference

at java.util.Calendar.setTime(Calendar.java:1089)

at java.text.SimpleDateFormat.format(SimpleDateFormat.java:953)

at java.text.SimpleDateFormat.format(SimpleDateFormat.java:946)

at java.text.DateFormat.format(DateFormat.java:337)

Answer 1

在这里你创建一个没有生日的用户..

// Is this even the format that user.getBday() returns? 
SimpleDateFormat dateFormat = new SimpleDateFormat("d/M/yyyy");
Date myDate = null;
try {
     // If not, this is wrong 
    myDate = dateFormat.parse(birthday);
    Log.d("myDate", birthday);  // Do you see this in the logs? 
} catch (ParseException e) {
    e.printStackTrace();  // or this? 
}

// Both these lines should be within the try block 
// You're not sure if the Date was assigned 
SimpleDateFormat timeFormat = new SimpleDateFormat("d/M");
String birthdayData = timeFormat.format(myDate);

然后你尝试解析什么，所以打印出一个错误，你会抓住它，但是然后继续重新格式化它，但是不要抓住

private Date birthday; 

public Date getBday() { return this.birthday==null ? new Date() : this.birthday ; }

就个人而言，如果没有给出生日

，我会让用户对象返回当天的Date对象

String birthday = " ";
for (int i=0;i<bdayList.size();i++)
{
    User user=bdayList.get(i);
    birthday =user.getBday();
}

或者你需要输入构造函数，而不是使用空的。

其次，此循环不执行任何操作，因此您可以将其删除..或实际使用其中的值而不是立即创建空白用户/生日

public List<String> getBirthdayData(List<User> bdayList) {
    List<String> dates = new ArrayList<>();
    SimpleDateFormat timeFormat = new SimpleDateFormat("d/M");
    SimpleDateFormat dateFormat = new SimpleDateFormat("d/M/yyyy");
    for (User u : bdayList) {
        String birthday =u.getBday();
        Log.d("myDate", birthday);
        try {
            Date d = dateFormat.parse(birthday);
            dates.add(timeFormat.format(d));
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
    return dates;
}

例如，如果您打算从用户列表中格式化所有生日字符串

{{1}}

当前日期 - 匹配ArrayList

1 个答案: