java - 如何将微调器的第一个位置设置为空

Question

我有一个微调器，我正在填充一个 ArrayAdapter 对象，但我需要此数组的第一个位置始终为空或出现类似“选择一个对象”的内容。我在这里搜索论坛但没有成功，ArrayList String 或 spinner.setPrompt 的解决方案不起作用 =/

ArrayList<Object> objects = null;

objects= findMyObjects();

final ArrayAdapter<Object> adapterObjects = new ArrayAdapter<Object>(contexto, R.layout.spinner_item, objects);
mySpinner = (Spinner) viewPai.findViewById(R.id.s_spinner);
mySpinner.setAdapter(adapterObjects);
adapterObjects.notifyDataSetChanged();
mySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {

                }

                @Override
                public void onNothingSelected(AdapterView<?> adapterView) {

                }
            });



public ArrayList<Object> findMyObjects() {
        allObjects = new ArrayList<Object>();
        Cursor cursor;

        String sql = "SELECT * FROM Object; ";
        cursor = database.rawQuery(sql, null);

        if (cursor.getCount() >= 0) {
            cursor.moveToFirst();
            while (!cursor.isAfterLast()) {
                Objects object = new Objects();
                object.setId(cursor.getLong(0));
                allObjects.add(object);
                cursor.moveToNext();
            }
        }
        cursor.close();
        return allObjects;
    }

Answer 1

你可以试试这个例子。链接:http://android--code.blogspot.in/2015/08/android-spinner-hint.html