1，ListView是手机中非常广泛的一种组件
2，ListView于其他AutoComplete、Spinner组件类似，它们都需要一个供显示的列表项，这都需要借助于内容Adapter了，内容Adapter负责提供需要现实的列表项

public class MyListView extends Activity {
 
    private ListView listView;
    //private List<String> data = new ArrayList<String>();
    @Override
    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
         
        listView = new ListView(this);
        listView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1,getData()));
        setContentView(listView);
    }
     
     
     
    private List<String> getData(){
         
        List<String> data = new ArrayList<String>();
        data.add("测试数据1");
        data.add("测试数据2");
        data.add("测试数据3");
        data.add("测试数据4");
         
        return data;
    }
}

demo如下：总是报同一个错误有可能是编辑器的问题了，重启了一下AndroidStuido就好了：

public class MainActivity extends AppCompatActivity {
   // private Context mContext;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        String json;
       // int i=0;
      List<String> listS=new ArrayList<String>();
       ListView listView=(ListView) findViewById(R.id.list1);
        //ArrayAdapter<String> arrayAdapter;
      //String[] arr={"松武","八戒","牛魔王"};
         //DynamicBean dynamicBean;
        Gson gson = new Gson();
        json=ReadJsonFile.getJson("dynamic.json",MainActivity.this);
        Root root=gson.fromJson(json,Root.class);
        for(int i=0;i<root.getDynamic().size();i++){
         //   root.getDynamic().get(i);
         //   Toast.makeText(this,root.getDynamic().get(i).getUsername(), Toast.LENGTH_SHORT).show();
            listS.add(root.getDynamic().get(i).getUsername());
        }
       listView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1,listS));
       // root.getDynamic().get(4).getUsername();
       //Toast.makeText(this,root.getDynamic().get(1).getUsername(), Toast.LENGTH_SHORT).show();
    //   dynamicBean=gson.fromJson(jsonStr,type);
      //  dynamicBean.getUsername().length();
        //将Java集合转换为json
      //  String json2 = gson.toJson(List);        System.out.println(json2);
    }
}