如何从 Firebase 获取字符串列表以填充 Spinner [英] How to get a String List from Firebase to fill a Spinner

问题描述

我的数据库是这样排列的:

my database is arranged like this:

我想从 areaName 获取所有值作为字符串列表或任何形式的列表，并使用它来填充 Spinner.我遇到的问题是它只检索最后一个值(在本例中为纽约").这是我的实际代码:

I want to get all the values from areaName as a String List or any form of list and use it to populate a Spinner. The problem I am getting is that it only retrieves the last value (in this case "New York"). This is my actual code:

fDatabaseRoot.child("areas").addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshot areaSnapshot: dataSnapshot.getChildren()) {
                String areaName = areaSnapshot.child("areaName").getValue(String.class);

                Spinner areaSpinner = (Spinner) findViewById(R.id.spinner);
                final String[] areas = {areaName};
                ArrayAdapter<String> areasAdapter = new ArrayAdapter<String>(UAdminActivity.this, android.R.layout.simple_spinner_item, areas);
                areasAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                areaSpinner.setAdapter(areasAdapter);
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

推荐答案

我没有测试该代码，但或多或​​少，这就是您必须做的:

I didn't test that code but, more or less, that is what you have to do:

fDatabaseRoot.child("areas").addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        // Is better to use a List, because you don't know the size 
        // of the iterator returned by dataSnapshot.getChildren() to
        // initialize the array
        final List<String> areas = new ArrayList<String>();

        for (DataSnapshot areaSnapshot: dataSnapshot.getChildren()) {
            String areaName = areaSnapshot.child("areaName").getValue(String.class);
            areas.add(areaName);
        }

        Spinner areaSpinner = (Spinner) findViewById(R.id.spinner);
        ArrayAdapter<String> areasAdapter = new ArrayAdapter<String>(UAdminActivity.this, android.R.layout.simple_spinner_item, areas);
        areasAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        areaSpinner.setAdapter(areasAdapter);
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {

    }
});

希望能帮到你！

问候.

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