我如何在CalendarView中显示目标的名称? [英] How i can display name of my target in CalendarView?

问题描述

此刻，我设法将date字段添加到模型Target中. 您可以在屏幕上看到的结构:

At the moment I managed to add a date field to my model Target. The structure you can see in the screen:

我还有一个片段在其中显示日历.如何通过单击日期来判断是否有针对该日期创建的目标?

Also i have a fragment where I display the calendar. How can I tell by clicking on a date if there is a target created for that date?

class CalendarFragment : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_calendar, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        setupViews()
    }

    private fun setupViews() {
        calendarView.setOnDateChangeListener { view, year, month, dayOfMonth ->
            dateView.text = //name of Target
        }
    }
}

例如，现在我只在日历中显示带有下一个代码的日期:

For example now i display only date in calendar with next code:

dateView.text = "Selected date is " + dayOfMonth + "/" + (month + 1) + "/" + year

问:我如何显示特定日期的目标名称?

UPD: 现在，我将此代码插入片段中，该片段取自 answer :

UPD: Right now i insert this code in my fragment, which i took from this answer:

val uid = FirebaseAuth.getInstance().currentUser!!.uid
        val rootRef = FirebaseDatabase.getInstance().reference
        val targetsRef = rootRef.child("targets").child("users").child(uid).child("targets")
        val query = targetsRef.orderByChild("date")
        val valueEventListener = object : ValueEventListener {
            override fun onDataChange(dataSnapshot: DataSnapshot) {
                for (ds in dataSnapshot.children) {
                    val name = ds.child("name").getValue(String::class.java)
                    Log.d("some", name)
                }
            }

            override fun onCancelled(databaseError: DatabaseError) {
                Log.d("some", databaseError.getMessage()) //Don't ignore errors!
            }
        }
        query.addListenerForSingleValueEvent(valueEventListener)

但是现在当我进入片段时，无论日历中选择的日期如何，我都会获得创建的所有目标的名称.

But now when I go into the fragment I get the names of all the targets created regardless of the selected date in the calendar.

推荐答案

根据前面的注释，您确认当某人单击日历中的日期以查询使用该日期的targets节点时，您是否想要一个或多个结果.但是第一件事.

According to the earlier comments, you confirmed that you want when someone is clicking on a date in the calendar to query the targets node using that date to find one or more results. But first thing first.

出于搜索目的，可以将date存储为字符串，因为您可以使用比较whereEqualTo()方法，但是如果要订购结果，则由于

For searching purposes, storing the date as a String might work, since you can use for comparation whereEqualTo() method but if you want to order the results, it won't work since the strings are order lexicographically. So you might consider storing the date as a ServerValue.TIMESTAMP, as explained in my answer from the following post:

• 此外，我将为您提供特定用途的解决方案，其中date是一个字符串，但是如果您考虑使用上述解决方案，则可以稍后对其进行更改.因此，我将使用以下字符串作为选定日期:

  Furthermore, I will provide you the solution for your particular use, where the date is a String but can simply change it later if you'll consider using the solution above. So I will use as a selected date the following String:

  val selectedDate = "24 October 2019"
  

  假设此值来自您选择日历中的日期，请尝试以下代码:

  Assuming that this value is coming from the selection of the date from your calendar, please try the code below:

  val uid = FirebaseAuth.getInstance().currentUser!!.uid
  val rootRef = FirebaseDatabase.getInstance().reference
  val targetsRef = rootRef.child("targets").child("users").child(uid).child("targets")
  val query = targetsRef.orderByChild("date").equalTo(selectedDate)
  val valueEventListener = object : ValueEventListener {
      override fun onDataChange(dataSnapshot: DataSnapshot) {
          for (ds in dataSnapshot.children) {
              val name = ds.child("name").getValue(String::class.java)
              Log.d(TAG, name)
          }
      }
  
      override fun onCancelled(databaseError: DatabaseError) {
          Log.d(TAG, databaseError.getMessage()) //Don't ignore errors!
      }
  }
  query.addListenerForSingleValueEvent(valueEventListener)
  

  在这种情况下，您的logcat中的结果将是:

  In this case, the result in your logcat will be:

  target
  

  无论日历中选择的日期如何，我都会获得创建的所有目标的名称.

  I get the names of all the targets created regardless of the selected date in the calendar.

  您得到所有​​日期，因为您忘记了呼叫.equalTo(selectedDate).所以请更改:

  You get all the dates because you forgot to call .equalTo(selectedDate). So please change:

  val query = targetsRef.orderByChild("date")
  

  到

  val query = targetsRef.orderByChild("date").equalTo(selectedDate)
  

  这篇关于我如何在CalendarView中显示目标的名称?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！