android sdk---spinner添加删除实例

来源：互联网发布：91kge网络在线ktv 编辑：程序博客网时间：2024/06/05 09:19

需求：

选中下拉列表中的选项，textview中显示对应字符串

点击“添加”按钮，将字符串添加到下拉列表中

点击“删除”按钮，将选中字符串从下拉列表中删除

效果图：

代码：

private static final String[] countriesStr={"beijing" ,"shanghai","tianjing"};
protected static final Object NULL = null;
private TextView myTextView;
private EditText myEditText;
private Button myButton_add;
private Button myButton_del;
private Spinner mySpinner;
private ArrayAdapter<String> adapter;
private List<String> allcountries;

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

        /*把字符串添加到list列表中*/
        allcountries = new ArrayList<String>();
        for(int i = 0; i < countriesStr.length;i++)
        {
        allcountries.add(countriesStr[i]);
        }

        /*将allcountries传入给adapter*/
        adapter = new ArrayAdapter<String>(this,
          android.R.layout.simple_spinner_item, allcountries);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        myTextView = (TextView)findViewById(R.id.textView2);
        myEditText = (EditText)findViewById(R.id.editText1);
        myButton_add = (Button)findViewById(R.id.button1);
        myButton_del = (Button)findViewById(R.id.button2);
        mySpinner = (Spinner)findViewById(R.id.spinner1);

        /*将adapter传给spinner*/
        mySpinner.setAdapter(adapter);

        myButton_add.setOnClickListener(new Button.OnClickListener()
        {

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    String newCountry = myEditText.getText().toString();
    for(int i = 0; i < adapter.getCount(); i++)
    {
     if(newCountry.equals(adapter.getItem(i)))
     {
      return;
     }
    }
    if(!newCountry.equals(""))
    {
     adapter.add(newCountry);
     int position = adapter.getPosition(newCountry);
     mySpinner.setSelection(position);
     myEditText.setText("");
    }
   }

        });

        myButton_del.setOnClickListener(new Button.OnClickListener()
        {

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub

    if(mySpinner.getSelectedItem()!= NULL)
    {
     adapter.remove(mySpinner.getSelectedItem().toString());
     myEditText.setText("");
     if(adapter.getCount() == 0)
     {
      myTextView.setText("");
     }
    }
   }

        });

        mySpinner.setOnItemSelectedListener(
          new Spinner.OnItemSelectedListener()
          {

     @Override
     public void onItemSelected(AdapterView<?> arg0, View arg1,
       int arg2, long arg3) {
      // TODO Auto-generated method stub
      myTextView.setText(arg0.getSelectedItem().toString());
     }

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

     }

          });

重点：

在下拉列表中删除和添加的动作，其实是在adapter中实现的，spinner随时显示adapter中的信息

数据的传输过程：String->ArrayList->ArrayAdapter->spinner

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