如何访问列表中的第二个参数？

Posted 2023-04-15

【中文标题】如何访问列表中的第二个参数？

【英文标题】：How can I access the second argument in the list?

【发布时间】：2013-07-25 17:22:35

【问题描述】：

我想知道如何访问列表中的第二项？我的意思是字符串输出这个：

07-17 21:15:38.723: D/MY APP(15806): feeling=joyful

但我只希望它读“快乐”

这是我的代码：

公共类 FeelingsMain 扩展 Activity

private static final String TAG = "MY APP";

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

    initList();
    ListView lv = (ListView) findViewById(R.id.pageLayout);
    // design the listview with the adapter
    SimpleAdapter simpleAdpt = new SimpleAdapter(this, feelingsList,
            android.R.layout.simple_list_item_1,
            new String[]  "feeling" , new int[]  android.R.id.text1 );

    lv.setAdapter(simpleAdpt);

    lv.setOnItemClickListener(viewNeeds);



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

private void initList() 
    // populate the feelingsList
    feelingsList.add(createFeeling("feeling", "wonderful"));
    feelingsList.add(createFeeling("feeling", "content"));
    feelingsList.add(createFeeling("feeling", "joyful"));
    feelingsList.add(createFeeling("feeling", "tired"));
    feelingsList.add(createFeeling("feeling", "gay"));
    feelingsList.add(createFeeling("feeling", "sad"));
    feelingsList.add(createFeeling("feeling", "amazing"));



private HashMap<String, String> createFeeling(String key, String name) 
    HashMap<String, String> feeling = new HashMap<String, String>();
    feeling.put(key, name);

    return feeling;



OnItemClickListener viewNeeds = new OnItemClickListener() 


    @Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
            long arg3) 
        // TODO Auto-generated method stub
        // create variable for database input
        String feeling = feelingsList.get(arg2).toString();
        Log.d(TAG, feeling);

        Intent gotoNeeds = new Intent(FeelingsMain.this, Needs.class);
        gotoNeeds.putExtra("aFeeling", feeling);
        startActivity(gotoNeeds);
    

;

等于感觉列表的字符串感觉给了我问题。是否有一些方法可以让我访问数组的不同部分，get 方法似乎只返回两个元素。

【问题讨论】：

...您有一个地图列表，并且您正在将地图转储到给定的索引处。转储地图值。还有，嗯。

不要使用 toString ... 将其转换为列表项类 ..

通过创建ArrayList of HashMaps 不确定您在做什么。

我也没有，我只做了几个星期，在黑暗中磕磕绊绊，休息一下。

【参考方案1】：

看这个链接：Android - Get value from HashMap

Map<String, String> map = new HashMap<String, String>();
map.put("Color1","Red");
map.put("Color2","Blue");
map.put("Color3","Green");
map.put("Color4","White");

 System.out.println(map);
 // Color4=White, Color3=Green, Color1=Red, Color2=Blue        

  System.out.println(map.get("Color2")); // Blue

 System.out.println(map.keySet());
  // [Color4, Color3, Color1, Color2]

for (Map.Entry<String,String> entry : map.entrySet()) 
   System.out.printf("%s -> %s%n", entry.getKey(), entry.getValue());

// Color4 -> White

// 颜色3 -> 绿色 // 颜色1 -> 红色 // 颜色2 -> 蓝色

The credit is for @polygenelubricants

【参考方案2】：

@Tobiel 和其他人是对的：使用 HashMap.getValue(key) 方法输出值。在您的情况下，它将是：

OnItemClickListener viewNeeds = new OnItemClickListener() 


@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
        long arg3) 
    // TODO Auto-generated method stub
    // create variable for database input
    String feeling = feelingsList.get(arg2).get("feeling").toString();  // <<- changes here
    Log.d(TAG, feeling);

    Intent gotoNeeds = new Intent(FeelingsMain.this, Needs.class);
    gotoNeeds.putExtra("aFeeling", feeling);
    startActivity(gotoNeeds);


;