Question

我想用HaspMap类创建一个listview活动来插入行星，但文本没有显示。这是代码

ListView类 package com.thenextgeneration.listviewtest;

    import java.util.ArrayList;

    import java.util.HashMap;

    import java.util.List;

    import java.util.Map;


    import android.app.Activity;

    import android.os.Bundle;

    import android.widget.ListView;

    import android.widget.SimpleAdapter;


    public class Second extends Activity{


    ListView listview;


    @Override

    protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second);

    initList();

    listview = (ListView) findViewById(R.id.listView1);

    SimpleAdapter simpleAdpt = new SimpleAdapter(this, planetsList, 
    android.R.layout.simple_list_item_2, new String[] {"planet"}, new 
    int[] {android.R.id.text2});
    listview.setAdapter(simpleAdpt);

    }


    List<Map<String, String>> planetsList = new ArrayList<Map<String, 
    String>>();


    private void initList() {
    // TODO Auto-generated method stub
    planetsList.add(createPlanet("planet", "Mercury"));
    planetsList.add(createPlanet("planet", "Umaru Musa Yaradua 
    University"));
    planetsList.add(createPlanet("planet", "Jupiter"));
    planetsList.add(createPlanet("planet", "Earth"));
    planetsList.add(createPlanet("planet", "Mars"));
    planetsList.add(createPlanet("planet", "Venus"));
    planetsList.add(createPlanet("planet", "Uranus"));
    planetsList.add(createPlanet("planet", "Saturn"));
    planetsList.add(createPlanet("planet", "Neptune"));


    }


    private HashMap<String, String> createPlanet(String key, String 
    name) {
    // TODO Auto-generated method stub
    HashMap<String, String> planet = new HashMap<String, String>();
    return planet;

    }




    }

XML布局

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res   /android"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
         >
        </ListView>

    </RelativeLayout>

它显示列表但是有一个空文本，我已经在我的设备中安装了应用程序vut仍然只显示没有任何内容的列表

Answer 1

将您的方法更改为：

 private HashMap<String, String> createPlanet(String key, String 
        name) {
        // TODO Auto-generated method stub
        HashMap<String, String> planet = new HashMap<String, String>();
        planet.put(key,name);
        return planet;

        }

Answer 2

您的代码遗失了。您首先将planetsList添加到适配器，然后初始化并为planetsList赋值。首先初始化它，在其中放入值，然后发送到适配器或在代码中使用带适配器的notifydatasetchanged。

Answer 3

这是你的答案，你已经命名为“android.R.id.text2”而不是“android.R.id.text1”。我建议你按顺序编码。请享用！

ListView listview;
List<Map<String, String>> planetsList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second);
    planetsList = new ArrayList<Map<String, String>>();
    initList();

    listview = new ListView(this);

    SimpleAdapter simpleAdpt = new SimpleAdapter(this, planetsList,
            android.R.layout.simple_list_item_1, new String[] { "planet" },
            new int[] { android.R.id.text1 });
    listview.setAdapter(simpleAdpt);
    setContentView(listview);

}

private void initList() {

    Map<String, String> item;
    item = new HashMap<String, String>();
    item.put("planet", "Mercury");
    planetsList.add(item);
    item = new HashMap<String, String>();
    item.put("planet", "Jupiter");
    planetsList.add(item);
    item = new HashMap<String, String>();
    item.put("planet", "Mars");
    planetsList.add(item);
}

Android Listview不显示列表内容

3 个答案: