在 Android 中删除选定的微调器项目

Question

我的活动中有微调器，它从 JSON 数据中设置项目，当我从微调器中选择任何项目并设置到微调器中时，我已经正确完成了所有这些事情。但是当我想从微调器中删除选定的项目时我遇到了异常：

E/AndroidRuntime(1022): java.lang.UnsupportedOperationException"

和

E/AndroidRuntime(1022):atandroid.widget.ArrayAdapter.remove(ArrayAdapter.java:212)

在

的代码行

E/AndroidRuntime(1022):at com.spinnerdemo.SpinDemo$1.onItemSelected(SpinDemo.java:102)

这是我的代码：

public class SpinDemo extends Activity {

    private static String strUrl = "http://192.168.1.61/jyoti/android_app/all_questions.php";
    private static String TAG_ID = "id";
    private static String TAG_CODE = "q_prefix";
    private static String TAG_CODE_ARR = "Questions";

    JSONArray jsonArray = null;
    Spinner codeSpinner, spinner2;
    EditText edTextSpinnerItem;
    String[] items;

    String strEdtext;
    String strid , strcode ;
    ArrayList<String> codeList;
    public  ArrayAdapter<String> adapter ;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        codeList = new ArrayList<String>();
        codeSpinner = (Spinner) findViewById(R.id.spinner2);

        JSONParser jParser = new JSONParser();
        JSONObject json = jParser.getJSONFromUrl(strUrl);
        try
        {
            jsonArray = json.getJSONArray(TAG_CODE_ARR);

             // looping through All Contacts
             final String[] items = new String[jsonArray.length()];

             for(int i = 0; i < jsonArray.length(); i++)
             {
                 JSONObject c = jsonArray.getJSONObject(i);

                // Storing each json item in variable

                    strid = c.getString(TAG_ID);
                    strcode = c.getString(TAG_CODE);
                    items[i] = c.getString(TAG_CODE);
                    System.out.println("Hello events " + items);        

                    adapter = new ArrayAdapter<String>(this,
                            android.R.layout.simple_spinner_item,items);
                    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    codeSpinner.setAdapter(adapter);

             }
        }

        catch (JSONException e) {
            e.printStackTrace();
        }


        codeSpinner.setOnItemSelectedListener(new OnItemSelectedListener()
        {


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

                String anyvariable=String.valueOf(codeSpinner.getSelectedItem());
                System.out.println("anyvariable = " + anyvariable);
                edTextSpinnerItem=(EditText)findViewById(R.id.editText_SpinnerItem);
                edTextSpinnerItem.setText(anyvariable);
                System.out.println("edTextSpinnerItem " + edTextSpinnerItem);


                String t = adapter.getItem(pos);
                System.out.println("Get The Item Position From Adapter = " + t);




                adapter.remove(t);
                adapter.notifyDataSetChanged();
                codeSpinner.setAdapter(adapter);
                //mySpinner.setAdapter(m_adapterForSpinner);

                //adapter.remove((String)codeSpinner.getSelectedItem());
                //adapter.notifyDataSetChanged();
                //System.out.println("Item is Removed From The Spinner Drop Dwon List");



            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) 
            {
                // TODO Auto-generated method stub

            }
        });

    }



}

Answer 1

我认为问题是由于删除了实际选择的元素引起的 尝试对项目使用列表而不是数组： http://developer.android.com/reference/android/widget/ArrayAdapter.html#ArrayAdapter(android.content.Context,%20int,%20int,%20java.util.List)

然后在on item中选择使用

items.remove(t);

代替：

adapter.remove(t);

通过此更改，您从 ArrayList(List) 而不是从适配器中删除项目。 适配器 notifyDataSetChanged 捕获 List 上的变化并刷新 spinner

Answer 2

试试这个..

1) 在for 循环之后给spinner setadapter

2) 如果您需要删除任何项目。您需要使用ArrayList 这是简单的方法。

我在一些更改后发布了代码。

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        codeList = new ArrayList<String>();
        codeSpinner = (Spinner) findViewById(R.id.spinner2);

        JSONParser jParser = new JSONParser();
        JSONObject json = jParser.getJSONFromUrl(strUrl);
        try
        {
            jsonArray = json.getJSONArray(TAG_CODE_ARR);

             // looping through All Contacts
             final String[] items = new String[jsonArray.length()];

             for(int i = 0; i < jsonArray.length(); i++)
             {
                 JSONObject c = jsonArray.getJSONObject(i);

                // Storing each json item in variable

                    strid = c.getString(TAG_ID);
                    strcode = c.getString(TAG_CODE);
                    items[i] = c.getString(TAG_CODE);
                    System.out.println("Hello events " + items);  
                    codeList.add(strcode);

             }

adapter = new ArrayAdapter<String>(this,
                            android.R.layout.simple_spinner_item,codeList);
                    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    codeSpinner.setAdapter(adapter);
        }

        catch (JSONException e) {
            e.printStackTrace();
        }


        codeSpinner.setOnItemSelectedListener(new OnItemSelectedListener()
        {


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

                String anyvariable=String.valueOf(codeSpinner.getSelectedItem());
                System.out.println("anyvariable = " + anyvariable);
                edTextSpinnerItem=(EditText)findViewById(R.id.editText_SpinnerItem);
                edTextSpinnerItem.setText(anyvariable);
                System.out.println("edTextSpinnerItem " + edTextSpinnerItem);


                String t = adapter.getItem(pos);
                System.out.println("Get The Item Position From Adapter = " + t);



                Object t2 = adapter.getItem(pos);
        Log.v("t2", ""+t2);
        codeList.remove(t2);
        adapter.notifyDataSetChanged();


            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) 
            {
                // TODO Auto-generated method stub

            }
        });

    }