自定义视图布局 - ＆QUOT;清单＆LT;地图＆GT;不能被转换为List＆LT ;?扩展地图＆LT;字符串，＆GT;＆GT; ＆QUOT; [英] Custom View Layout - " List<Map> cannot be converted to List<? extends Map<String,?>> "

问题描述

我有允许对列表中的项目单击自定义列表视图。

I have a custom list view which allows clicking on items in the list.

在code的效果很好，类似于谷歌的自己的网站的例子很多，并成功编译，直到最近的Java，是这样的：

The code that worked well, similar to many examples on google's own site, and compiled successfully until more recent java, is this:

List<Map> myMapList = new ArrayList<Map>();
Map<String, String> myMap = new HashMap<String, String>();
private ListView myListView;

for (int i = 0; i < mydata.length(); i++) {

        JSONObject t = mydata.getJSONObject(i);

        myMap = new HashMap<String, String>();

        myMap.put("field_1", t.getString("field_1"));

    .... (more of these)

        myMapList.add(myMap);
}


String[] layoutNames = new String[] { "field_1", "field_2", "field_3",
                                      "field_4", "field_5" };

int[] layoutIDs = new int[] { R.id.field_1, R.id.field_2, R.id.field_3, 
                              R.id.field_4, R.id.field_5};

SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), 
     (List<? extends Map<String, ?>>) myMapList, R.layout.my_list_row, 
      layoutNames, layoutIDs );

    myListView.setAdapter(adapter);

起初，警告被赋予，但现在它是一个编译时错误。

At first, warnings were given, but now it is a compile-time error.

error: incompatible types: List<Map> cannot be converted to List<? extends Map<String,?>>

因此​​，如何我养活我的字符串/整数组合成列表与LT;>新规则

So how to I feed my String / Integer combo into List<> with the new rules?

解决方法注意：

答转到Aeshang，见下文。请注意，此解决方案还摆脱的需要，为（名单>）剧组，让行现在如下所示：

Answer Goes to Aeshang, see below. Note that this solution also gets rid of the need for the "(List>)" cast, so that line now reads:

SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), 
     myMapList, R.layout.my_list_row, layoutNames, layoutIDs );

对眼睛更容易了。

Easier on the eyes, too.

推荐答案

您需要更改此行

List<Map> myMapList = new ArrayList<Map>();

到

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

这篇关于自定义视图布局 - ＆QUOT;清单＆LT;地图＆GT;不能被转换为List＆LT ;?扩展地图＆LT;字符串，＆GT;＆GT; ＆QUOT;的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！