AndroidUI组件Spinner下拉列表详解

public class MainActivity extends AppCompatActivity {
  private String[] data;
  private List data1;
  private Spinner spinner;
  private ArrayAdapter adapter;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.spinner);
    spinner = (Spinner)findViewById(R.id.spinner);
    data = getResources().getStringArray(R.array.data);
    data1 = new ArrayList<>();
    for(int i = 1; i <10; i++){
      data1.add("这是第" + i +"个");
    }
    //data可以修改为data1，数据可以是数组也可以是集合
    adapter = new ArrayAdapter(this,android.R.layout.simple_spinner_dropdown_item,data);
    spinner.setAdapter(adapter);
  }
}

public class SpinnerActivity extends Activity implements OnItemSelectedListener {

  /**
  * 当item被选中时，会调用此方法
  */
  public void onItemSelected(AdapterView<&＃63;> parent, View view, 
      int pos, long id) {
    // An item was selected. You can retrieve the selected item using
    // parent.getItemAtPosition(pos)
  }
  /**
  * 当数据项的值设置为空时，就会调用此方法，通过调用adapter.clear()方法清空数据，并且刷新界面
  * 时，会调用次方法
  */
  public void onNothingSelected(AdapterView<&＃63;> parent) {
    // Another interface callback
  }
}