android - 微调器 getSelectedItem() 返回 null

Question

我在尝试访问 spn_make 上的 getSelectedItem().toString() 时遇到 NULL 指针异常。

        CustomAdapter adapter = new CustomAdapter(InfoActivity.this);
            spn_make.setAdapter(adapter);
            Log.i("Count", spn_make.getAdapter().getCount()+"");
            spn_make.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

                        @Override
                        public void onItemSelected(AdapterView<?> a, View v,
                                int pos, long arg3) {
                            Toast.makeText(InfoActivity.this, spn_make.getSelectedItem().toString(), Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onNothingSelected(AdapterView<?> a) {
                            // TODO Auto-generated method stub

                        }
                    });

请任何人帮助我。

Answer 1

要检索您必须编写的选定项目

a.getItemAtPosition(pos)

代替 spn_make.getSelectedItem()

Here是引用文档

改变这行代码

Toast.makeText(InfoActivity.this, spn_make.getSelectedItem().toString(), Toast.LENGTH_LONG).show();

为此:

Toast.makeText(InfoActivity.this, a.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();