处理微调器时出现空指针异常

Question

当我运行这段代码时，我得到一个空指针异常

            private void loadSpinnerData() {
        // database handler
        AttendAppDatasource db = new AttendAppDatasource(getApplicationContext());

        // Spinner Drop down elements
        List<String> clas = db.viewCol(AttendAppDbOpenHelper.COLUMN_CLASS);
        Log.i("Select Class","List Assigned");
        // Creating adapter for spinner
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, clas);

        // Drop down layout style - list view with radio button
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        // attaching data adapter to spinner
        spinner.setAdapter(dataAdapter);
    }

这是相关的日志输出

这是与列表对应的注销

Answer 1

您的微调器设置为null。您需要从资源中获取

Spinner spinner = (Spinner) findViewById(R.id.'spinner_id_name');

然后你可以设置你的适配器：）