Android开发中使用Spinner控件出现的问题

来源：互联网发布：同志软件有那些编辑：程序博客网时间：2024/06/05 17:18

我们在开发Android程序的时候，使用Spinner控件做联动操作的时候，总是提示所用的方法不对。下面先来看看吧

private Spinner citySpinner=null;
private Spinner areaSpinner=null;
private String[][] aredata=new String[][] {
   {"东城","西城","朝阳","大兴"},
   {"上海","浦东"},
   {"苏州","吴中","新区"},
   {"广州","天河"}
};
private ArrayAdapter<CharSequence> adadata=null;

/* (non-Javadoc)
* 联动选择
*/
@Override
protected void onCreate(Bundle savedInstanceState)
{
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  citySpinner = (Spinner) findViewById(R.id.city);
  areaSpinner=(Spinner)findViewById(R.id.area);
  citySpinner.setOnItemSelectedListener(new spinnerliandong());
}

private class spinnerliandong implements OnItemSelectedListener{

  @Override//当选择了某一项之后，联动产生选项
  public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3)
  {
   // TODO Auto-generated method stub
   adadata=new ArrayAdapter<CharSequence>(this, android.R.layout.simple_spinner_item, MainActivity.this.aredata[arg2]);
  }

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

  }

}

上面的红色部分总是会提示错误：The constructor ArrayAdapter<CharSequence>(MainActivity.spinnerliandong, int, String[]) is undefined

我们先来看看这个构造方法的原型吧：

public ArrayAdapter(Context context, int textViewResourceId, T[] objects)

Added in API level 1

Constructor

Parameters

contextThe current context.textViewResourceIdThe resource ID for a layout file containing a TextView to use when instantiating views.objectsThe objects to represent in the ListView.

注意到了，Context context这个是指整个你的Activity类，是不能用this这样简单的代替的。那我们就改一下吧：

adadata=new ArrayAdapter<CharSequence>(MainActivity.this, android.R.layout.simple_spinner_item, MainActivity.this.aredata[arg2]);

改成蓝色的这样就OK了 Acticity类.this

这样就不会再提示错误了