自定义可搜索微调控件在单击微调控件时抛出空指针异常 [英] Custom searchable spinner throws null pointer exception while clicking on the spinner

问题描述

主要活动

public class CustomSpinnerActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {


    ArrayList<String> data = new ArrayList<String>();
    ArrayList<String> data1 = new ArrayList<String>();
    ArrayList<String> data2 = new ArrayList<String>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.chit_spinner);
        //Getting the instance of Spinner and applying OnItemSelectedListener on it

        SearchableSpinner spin = (SearchableSpinner) findViewById(R.id.simpleSpinner) ;
        spin.setOnItemSelectedListener(this);

        //spinner variyable
        CloudDBConnection connect = new CloudDBConnection();
        Connection con = connect.CONN();
        if (con != null) {
            try {
                Statement statement = con.createStatement();
                String query = "select * from chitCardDet;";
                ResultSet rs = statement.executeQuery(query);
                //Toast.makeText(getApplicationContext(), "You are out.", Toast.LENGTH_SHORT).show();

                if (rs.next()) {

                    String custName = rs.getString(3);
                    if(custName.equals(null)){
                        custName = "NA";
                    }
                    String cell = rs.getString(8);
                    if(cell.equals(null)){
                        cell = "NA";
                    }
                    String city = rs.getString(9);
                    if(city.equals(null)){
                        city = "NA";
                    }
                    data.add(custName);
                    data1.add(cell);
                    data2.add(city);
                   // Toast.makeText(getApplicationContext(), custName+cell+city, Toast.LENGTH_SHORT).show();
                }else{
                    Toast.makeText(getApplicationContext(), "You are out.....", Toast.LENGTH_SHORT).show();
                }

                CustomSpinnerAdapter customAdapter=new CustomSpinnerAdapter(getApplicationContext(),data,data1,data2);
                spin.setAdapter(customAdapter);

                rs.close();
                statement.close();
                con.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        } else {
            Toast.makeText(getApplicationContext(), "Server Unable......", Toast.LENGTH_SHORT).show();
        }

    }


    //Performing action onItemSelected and onNothing selected
    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int position,long id) {
        Toast.makeText(getApplicationContext(), data.get(position), Toast.LENGTH_LONG).show();
    }

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

CustomSpiner适配器：

public class CustomSpinnerAdapter extends ArrayAdapter {
    Context context;
    ArrayList<String> data;
    ArrayList<String> data1;
    ArrayList<String> data2;
    LayoutInflater inflter;

    public CustomSpinnerAdapter(Context applicationContext, ArrayList<String> data, ArrayList<String> data1, ArrayList<String> data2) {
        super(applicationContext,custom_spinner_items);
        this.context = applicationContext;
        this.data = data;
        this.data1 = data1;
        this.data2 = data2;
        inflter = (LayoutInflater.from(applicationContext));
    }


    @Override
    public int getCount() {
        return data.size();
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        view = inflter.inflate(custom_spinner_items, null);
        TextView cust = (TextView) view.findViewById(R.id.custName);
        TextView mobile = (TextView) view.findViewById(R.id.mobileNumber);
        TextView cityname = (TextView) view.findViewById(R.id.city);
        cust.setText(data.get(i));
        mobile.setText(data1.get(i));
        cityname.setText(data2.get(i));
        return view;
    }
}

单击the spinner时抛出以下error message

NullpointerException:Attempt to invoke virtual method java.lang.String java.lang.Object.toString() on a null object reference

仅供参考：它在已加载时工作，但不能在单击微调控件时工作

请谁帮帮我……我正在尝试解决它，但我解决不了问题。

enter image description here

推荐答案

我想是因为订购的原因

Spinner sItems = (Spinner) findViewById(R.id.select_size_spinner);


  ArrayList<String> options = new ArrayList<>();
    options.add("custName");
    options.add("cell");
    options.add("city");

ArrayAdapter<String> langAdapter = new ArrayAdapter<String>(getActivity(), R.layout.spinner_text, options);
    langAdapter.setDropDownViewResource(R.layout.simple_spinner_dropdown);
    sItems.setAdapter(langAdapter);

sItems.setOnItemSelectedListener( new AdapterView.OnItemSelectedListener( )
{
    @Override
    public void onItemSelected( AdapterView< ? > parent, View view, int pos, long id )
    {
        String selected = String.valueOf(adapterView.getItemAtPosition(position));

        int  Select = Integer.parseInt(selected);

        Toast.makeText(getApplicationContext(), Select, Toast.LENGTH_SHORT).show();

     
    }

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

    }
});

spner_ext.xml：

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@android:id/text1"
    style="?attr/spinnerDropDownItemStyle"
    android:layout_width="match_parent"
    android:layout_height="?dropdownListPreferredItemHeight"
    android:ellipsize="marquee"
    android:singleLine="true"
    tools:text="hello" />

Simple_spner_dropdown.xml文件

<?xml version="1.0" encoding="utf-8"?>
<CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    style="@style/spinnerDropDownItemStyle"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ellipsize="marquee"
    android:paddingBottom="5dp"
    android:paddingLeft="10dp"
    android:paddingRight="10dp"
    android:paddingTop="5dp"
    android:singleLine="true" />

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