如何遍历哈希图以获取每第四个键值对？

Question

我有一个这样的哈希图；

key value1

key value2

key value3

key value4

key1 value5

key1 value6

key1 value7

key1 value8

key2 value9

... and so on

现在我想把它放在一个包含四行的 ListView 中，在 row1 中，我想要：

key value1

key1 value5

key2 value9

key3 value13 and so on till end

在第 2 行，我想要：

key value2

key1 value6

key2 value10

key3 value14 and so on till end

然后在第 3 行和第 4 行中也是如此。总是只有 4 行。

我在迭代这个过程中遇到了麻烦。这是我写的代码，但它不起作用。

String[] fourrows = hashMap.get("KEY");

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

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

listHashMap.put("TA",  "ROW VALUE "+fourrows[i]);

for (int j=1;j<hashMap.entrySet().size();j+=4) {

String val = hashMap.values().toArray()[j].toString();

String key = hashMap.get(hashMap.keySet().toArray()[0]).toString();

listHashMap.put("IA", key);

listHashMap.put("XA", val);

incmStmtList.add(listHashMap);

}

}

//Then I pass TA, IA and XA to a simple list adapter and add it to a listView.

incmAdapter = new SimpleAdapter(getContext(), incmStmtList,R.layout.content_results, new String[]{"TA", "IA", "XA"},new int[]{R.id.ta, R.id.ia, R.id.tota});

listView.setVerticalScrollBarEnabled(true);

listView.setAdapter(incmAdapter);

谢谢。

Answer 1

而不是使用 HashMap 使用 Multimap。并基于键获取 Collection 对象中的值。然后从每个 Collection 在所有列表中添加一个值。Multimap myList = ArrayListMultimap.create();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key","value1");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key","value2");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key","value3");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key","value4");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key1","value5");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key1","value6");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key1","value7");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key1","value8");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key2","value9");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key2","value10");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key2","value11");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key2","value12");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key3","value13");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key3","value14");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key3","value15");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; myList.put("key3","value16");然后从列表中获取所有密钥&nbsp; Set myKeySet = myList.keySet();&nbsp; Object[] keys = myKeySet.toArray();现在您已经设置了所有密钥。然后&nbsp; &nbsp; HashMap<String, String> listHashMap1 = new HashMap<>();&nbsp; &nbsp; HashMap<String, String> listHashMap2 = new HashMap<>();&nbsp; &nbsp; HashMap<String, String> listHashMap3 = new HashMap<>();&nbsp; &nbsp; HashMap<String, String> listHashMap4 = new HashMap<>();现在将值添加到每个列表&nbsp; for(int i=0;i<4;i++){&nbsp; &nbsp; &nbsp; &nbsp; List<String> keyval = (List)myList.get((String)keys[i]);&nbsp; &nbsp; &nbsp; &nbsp; listHashMap1.put((String)keys[i],keyval.get(0));&nbsp; &nbsp; &nbsp; &nbsp; listHashMap2.put((String)keys[i],keyval.get(1));&nbsp; &nbsp; &nbsp; &nbsp; listHashMap3.put((String)keys[i],keyval.get(2));&nbsp; &nbsp; &nbsp; &nbsp; listHashMap4.put((String)keys[i],keyval.get(3));&nbsp; &nbsp; &nbsp;}现在您已经设置了四行列表。这个 Multimap 使用的是谷歌番石榴。所以你需要在你的 gradle 中实现番石榴，如下所示： implementation 'com.google.guava:guava:26.0-jre'

Answer 2

从您提供的代码看来，源hashMap的类型是Map<String, String[]>。您可以遍历地图的条目，并为每个条目将四个值存储在不同的结果容器中。由于您指出结果容器也应该是地图：&nbsp; &nbsp; Map<String, String> one = new HashMap<>();&nbsp; &nbsp; Map<String, String> two = new HashMap<>();&nbsp; &nbsp; Map<String, String> three = new HashMap<>();&nbsp; &nbsp; Map<String, String> four = new HashMap<>();&nbsp; &nbsp; hashMap.entrySet().forEach(entry -> {&nbsp; &nbsp; &nbsp; &nbsp; String[] values = entry.getValue();&nbsp; &nbsp; &nbsp; &nbsp; one.put(entry.getKey(), values[0]);&nbsp; &nbsp; &nbsp; &nbsp; two.put(entry.getKey(), values[1]);&nbsp; &nbsp; &nbsp; &nbsp; three.put(entry.getKey(), values[2]);&nbsp; &nbsp; &nbsp; &nbsp; four.put(entry.getKey(), values[3]);&nbsp; &nbsp; });注意：假设每个键总是正好有四个值。