如何在 TextView 中显示来自 Firebase 的一组数字的总和。

huangapple
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英文:

how can one display the sum of a group of numbers from firebase in a texview

问题

我正在使用 Android Firebase，已成功从 Firebase 获取一组值的总和并在 Logcat 中显示它。我想将这个总和显示在 TextView 中，我该如何做？以下是我的代码：

  1. databaseReference.addValueEventListener(new ValueEventListener() {
  3.      public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  4.             heroList.clear();
  5.             int total = 0;
  7.             for(DataSnapshot artistSnapshot: dataSnapshot.getChildren()){
  9.                 Integer rating = artistSnapshot.child("editTextCalories").getValue(Integer.class);
  11.                 Hero hero = artistSnapshot.getValue(Hero.class);
  12.                 heroList.add(hero);
  14.                 total += Hero.getTotal(rating);
  16.             }
  17.             Log.d("Tag", total + "");
  18.             NameList adapter = new NameList(MainActivity.this, heroList);
  19.             listView.setAdapter(adapter);
  21.             // 将 total 显示在 TextView 中
  22.             TextView textView = findViewById(R.id.your_text_view_id); // 替换为你的 TextView ID
  23.             textView.setText(String.valueOf(total));
  24.         }
  25.     });
英文:

Im working with android firebase and have managed to get the sum of a group of values from firebase and display it in logcat. Only i want to display this sum in a TextView, how would I do that? Here is my code

  1. databaseReference.addValueEventListener(new ValueEventListener() {
  3.      public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  4.             heroList.clear();
  5.             int total = 0;
  7.             for(DataSnapshot artistSnapshot: dataSnapshot.getChildren()){
  9.                 Integer rating = artistSnapshot.child("editTextCalories").getValue(Integer.class);
  11.                 Hero hero = artistSnapshot.getValue(Hero.class);
  12.                 heroList.add(hero);
  15.                 total += Hero.getTotal(rating);
  17.             }
  18.             Log.d("Tag", total + "");
  19.             NameList adapter = new NameList(MainActivity.this, heroList);
  20.             listView.setAdapter(adapter);
  23.         }

答案1

得分: 1

你需要在onDataChange中为文本视图设置值，基本上就在你已经记录它的同一位置：

  1. databaseReference.addValueEventListener(new ValueEventListener() {
  3.   public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  4.     heroList.clear();
  5.     int total = 0;
  7.     for(DataSnapshot artistSnapshot: dataSnapshot.getChildren()){
  9.         Integer rating = artistSnapshot.child("editTextCalories").getValue(Integer.class);
  11.         Hero hero = artistSnapshot.getValue(Hero.class);
  12.         heroList.add(hero);
  14.         total += Hero.getTotal(rating);
  16.     }
  17.     Log.d("Tag", total + "");
  18.     ((TextView)findViewById(R.id.myAwesomeTextView)).setText("" + total);
  19.     NameList adapter = new NameList(MainActivity.this, heroList);
  20.     listView.setAdapter(adapter);
  21.   }
  22. }
英文:

You'll need to set the value to the text view in onDataChange, pretty much in the same spot where you already log it:

  1. databaseReference.addValueEventListener(new ValueEventListener() {
  3.   public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  4.     heroList.clear();
  5.     int total = 0;
  7.     for(DataSnapshot artistSnapshot: dataSnapshot.getChildren()){
  9.         Integer rating = artistSnapshot.child("editTextCalories").getValue(Integer.class);
  11.         Hero hero = artistSnapshot.getValue(Hero.class);
  12.         heroList.add(hero);
  15.         total += Hero.getTotal(rating);
  17.     }
  18.     Log.d("Tag", total + "");
  19.     ((TextView)findViewById(R.id.myAwesomeTextView)).setText(""+total)
  20.     NameList adapter = new NameList(MainActivity.this, heroList);
  21.     listView.setAdapter(adapter);
  22.   }

huangapple
  • 本文由 发表于 2020年5月29日 06:53:15
  • 转载请务必保留本文链接：https://java.coder-hub.com/62075848.html
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