小编use*_*667的帖子

我正在尝试使用默认的空选定项创建一个微调器,但它显示了微调器选项中的第一个项.如果我将空值添加到我的字符串(这是spinner中的选择源),则在打开微调器后显示空行.我该怎么办？这是我正在使用的代码:

  String[] ch = {"Session1", "Session2", "Session3"};
  Spinner sp = (Spinner)findViewById(R.id.spinner1);
  TextView sess_name = findViewById(R.id.sessname);
  ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,ch);
  sp.setAdapter(adapter);

  adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

  sp.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener({
      @Override
      public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
          int index = arg0.getSelectedItemPosition();
          sess_name.setText(ch[index]);

          Toast.makeText(getBaseContext(), "You have selected item : " + ch[index], Toast.LENGTH_SHORT).show();
      }