在Android中使用Firebase数据填充ListView [英] Populating a ListView with firebase data in android

问题描述

我又回到了这个问题，但是我很接近:我有以下代码，试图在列表视图中显示Firebase值.

I am back with this question again, I am close though: I have the following code which I am trying to show the firebase values in a list view.

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mystatement);
        listview = (ListView) findViewById(R.id.listview);
        textView4 = (TextView) findViewById(R.id.textView4);
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, list);
        listview.setAdapter(adapter);
        dref = FirebaseDatabase.getInstance().getReference();


        DatabaseReference dref = FirebaseDatabase.getInstance().getReference();
        dref= dref.child("Expenditure");

        dref.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot snapshot) {
                for (DataSnapshot postSnapshot : snapshot.getChildren()) {
                    //Getting the data from snapshot
                    DogExpenditure dogExpenditure = postSnapshot.getValue(DogExpenditure.class);

                    //Adding it to a string
                    String expenses = "Amount: "+dogExpenditure.getAmount()+"\nReason for Use: "+dogExpenditure.getItem()+"\n\n";

                    String amount = dogExpenditure.getAmount();
                    String item = dogExpenditure.getItem();

                    System.out.println(expenses);


                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }


            public void onCancelled(FirebaseError firebaseError) {
                System.out.println("The read failed: " + firebaseError.getMessage());
            }
        });

当我运行此代码时，在我的android studio控制台中，我看到以下输出.这正是我想要的.但是，它没有显示在应用程序的布局视图中，而是显示了空白屏幕.

When I run this code, in my android studio console, I see the below output. Which is exactly what I want. But, it is not displaying in my layout view from the app, it shows a blank screen.

**03-07 15:15:05.777 32332-32332/com.example.moses.farm I/System.out: Amount: dd
03-07 15:15:05.779 32332-32332/com.example.moses.farm I/System.out: Reason for Use: dddd
03-07 15:15:05.782 32332-32332/com.example.moses.farm I/System.out: Amount: kwaraaaa
03-07 15:15:05.782 32332-32332/com.example.moses.farm I/System.out: Reason for Use: ayeeeee**

有人可以告诉我如何在我的应用程序中显示该输出，因为当前它未显示任何内容，但是在调试控制台中我可以看到它

推荐答案

//Just above onCreate
List<String> expenseList = new ArrayList<>();
ArrayAdapter<String> adapter;

//In value event listener
expenseList.add(expense)

if(expensList.size() == 1)
{
  adapter = new ArrayAdapter<>(getApplicationContext(),android.R.layout.simple_list_item_1,expensList);
  listView.setAdapter(adapter)
}
else if(expenseList.size() > 1)
{
  adapter.notifyDatasetChanged();
}

这篇关于在Android中使用Firebase数据填充ListView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！