改变旋转数据，android？

Question

我在我的活动中有两个旋转器，分别是类别和子类别.当我从类别旋转器中选择一些值时，我想在子类别旋转器中显示它的相关值/数据。我该怎么做？

   public class SellActivity extends Activity {
 private Spinner spinner1, spinner2;
 private String selectedOption;
 List<String> addItemList = new ArrayList<String>();
 String[] elCat = new String[] {"Mobile", "Television", "Computers","Home Appliances","Games","Others"}; 
 String[] veCat = new String[] {"Cars", "Buses", "Motorcycles","Others"}; 
 String[] reCat = new String[] {"Apartment", "Plot", "Office","Paying Guest","Others"}; 
 String[] hCat = new String[] {"Books", "Furniture", "Musical Instrument","Watches","Others"}; 
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sell);
    spinner1 = (Spinner) findViewById(R.id.categorySellSpinner);
    spinner2 = (Spinner) findViewById(R.id.subCategorySpinner);
    selectedOption=String.valueOf(spinner1.getSelectedItem());
    System.out.println(selectedOption);
    spinner1.setOnItemSelectedListener(new OnItemSelectedListener() {

        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1,
                int arg2, long arg3) {
            // TODO Auto-generated method stub
            if(selectedOption.equals("Electronics"))
            {
                Collections.addAll(addItemList, elCat); 
                ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(SellActivity.this,android.R.layout.simple_spinner_item, addItemList);
                dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter.notifyDataSetChanged();
                spinner2.setAdapter(dataAdapter);
            }
            else if(selectedOption.equals("Home - Lifestyle"))
            {
                Collections.addAll(addItemList, hCat); 
                ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(SellActivity.this,android.R.layout.simple_spinner_item, addItemList);
                dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter.notifyDataSetChanged();
                spinner2.setAdapter(dataAdapter);
            }
            else if(selectedOption.equals("Vehicles"))
            {
                Collections.addAll(addItemList, veCat); 
                ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(SellActivity.this,android.R.layout.simple_spinner_item, addItemList);
                dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter.notifyDataSetChanged();
                spinner2.setAdapter(dataAdapter);
            }
            else if(selectedOption.equals("Real Estate"))
            {
                Collections.addAll(addItemList, reCat); 
                ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(SellActivity.this,android.R.layout.simple_spinner_item, addItemList);
                dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                dataAdapter.notifyDataSetChanged();
                spinner2.setAdapter(dataAdapter);
            }
        }
        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

        }
    });

}

}

这是整个密码。数据不是changing....plus旧数据添加到它中

Answer 1

只要在任何情况下都这样做:-

Collections.addAll(addItemList, elCat);
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String(this,android.R.layout.simple_spinner_item, addItemList);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dataAdapter.notifyDataSetChanged();
spinner2.setAdapter(dataAdapter);

Answer 2

旧数据被添加是因为您没有清除要传递到适配器的集合，只是在向其添加新数据之前清除集合的内容。

试试这个:-

    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1,
            int arg2, long arg3) {
        // TODO Auto-generated method stub


        addItemList.clear();
        spinner2.setAdapter(null);


        if(selectedOption.equals("Electronics"))
        {
            Collections.addAll(addItemList, elCat); 

Answer 3

您的代码有许多问题：

-- spinner1的数据丢失了。从您的代码中，应该是：{"Electronics", "Home - Lifestyle", "Vehicles","Real Estate"}

-- spinner1上没有设置适配器

-不需要创建和使用列表addItemList

-不需要使用selectedOption来检查所选的项目。onItemClick()在int arg2中为您提供选定的项

--将notifyDataSetChanged()调用到没有设置为任何视图的适配器，什么都不会做。

-数组可以直接传递给ArrayAdapters，而不需要将它们转储到ArrayList中