android studio 菜鸟实战项目 之 spnner实现

1.简单实现效果图：

activity_main.xml文件：

<TextView    android:id="@+id/text"    android:layout_width="wrap_content"    android:layout_height="wrap_content"     /><Spinner    android:id="@+id/spinner"    android:layout_width="wrap_content"    android:layout_height="wrap_content"></Spinner>

MainActivity.java文件：

public class MainActivity extends AppCompatActivity  {    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.activity_main);        //实例化        textView=(TextView)findViewById(R.id.text);        spinner=(Spinner)findViewById(R.id.spinner);        textView.setText("您选择的城市北京");        //设置数据源        list=new ArrayList<String>();        list.add("北京");        list.add("上海");        list.add("广州");        list.add("深圳");        //新建arrayAdapter,android.R.layout.simple_spinner_item是调用android studio中默认的样式        adapter=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,list);        //adapter设置一个下拉列表        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);        //spinner加载适配器        spinner.setAdapter(adapter);        //实现监听事件        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {            @Override            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {                String cityName=adapter.getItem(position);                //String cityName=list.get(position);                textView.setText("您选择的城市是"+cityName);            }            @Override            public void onNothingSelected(AdapterView<?> parent) {

            }        });    }}

2.自定义实现：添加图标

mainActivity.xml文件：

<TextView    android:textSize="25sp"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:id="@+id/text" /><Spinner    android:layout_marginTop="10dp"    android:id="@+id/spinner"    android:layout_width="match_parent"    android:layout_height="wrap_content"></Spinner>

新添加的item.xml文件：

<ImageView    android:id="@+id/imge"    android:layout_width="wrap_content"    android:layout_height="wrap_content" /><TextView    android:layout_marginTop="5dp"    android:layout_marginLeft="30dp"    android:id="@+id/city"    android:textSize="25sp"    android:textColor="#ff0000"    android:layout_width="wrap_content"    android:layout_height="wrap_content" />

mainActivity.java文件：

public class MainActivity extends Activity implements AdapterView.OnItemSelectedListener{    private TextView textView;    private Spinner spinner;    private List<Map<String,Object>> dataList;    private SimpleAdapter adapter;    private String[] cityName={"上海","广州","北京","深圳","杭州","南京"};    private int[] icon={R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //实例化        textView=(TextView)findViewById(R.id.text);        textView.setText("您选择的城市是上海");        spinner=(Spinner)findViewById(R.id.spinner);        //准备数据源        dataList=new ArrayList<>();        //新建适配器,特别要注意对from和to两个变量的定义        adapter=new SimpleAdapter(this,getData(),R.layout.item,new String[]{"image","city"},new int[]{R.id.imge,R.id.city});        //加载适配器        spinner.setAdapter(adapter);        //实现监听事件        spinner.setOnItemSelectedListener(this);    }    private List<Map<String,Object>> getData(){        for(int i=0;i<cityName.length;i++){            Map<String,Object>map=new HashMap<>();            map.put("image",icon[i]);            map.put("city",cityName[i]);            dataList.add(map);        }        return dataList;    }

    @Override    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {        String city= dataList.get(position).toString();        textView.setText("您选择的城市是"+city);        Toast.makeText(this,"您选择的城市是"+city,Toast.LENGTH_SHORT).show();

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

    }}