使用Spinner实现下拉列表

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.AndroidCharacter;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener{

private TextView textView;
private Spinner spinner;
private List<String>list;
private ArrayAdapter<String>adapter;

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

textView = (TextView) findViewById(R.id.textView);
spinner = (Spinner) findViewById(R.id.spinner);
//1、设置数据源
list = new ArrayList<String>();
list.add("上海");
list.add("北京");
list.add("广州");
list.add("深圳");

//2、新建ArrayAdapter（数组适配器）
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,list);
//3、adapter设置一个下拉列表样式
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
//4、spinner加载适配器
spinner.setAdapter(adapter);
//5、spinner设置监听器
spinner.setOnItemSelectedListener(this);
}

@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
//通过adapter获取当前选择
String cityName = adapter.getItem(i);
//        String cityName = list.get(i);
textView.setText("您选择的城市是："+cityName);
}

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

}
}