Wsrtjtyk

I have a hashmap like this;

key value1

key value2

key value3

key value4

key1 value5

key1 value6

key1 value7

key1 value8

key2 value9

... and so on

Now I want to put this in a ListView which contains four rows, and in row1, I want:

key value1

key1 value5

key2 value9

key3 value13 and so on till end

And in row2, I want:

key value2

key1 value6

key2 value10

key3 value14 and so on till end

And then the same in rows 3 and 4. There are always only 4 rows.

I am having trouble iterating through this. Here is the code I wrote, but it doesn't work.

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);

Thanks.

Instead of using HashMap use Multimap. And based on key get the value in Collection object. then from each Collection add one one value on all the list.

Multimap myList = ArrayListMultimap.create();

            myList.put("key","value1");

            myList.put("key","value2");

            myList.put("key","value3");

            myList.put("key","value4");

            myList.put("key1","value5");

            myList.put("key1","value6");

            myList.put("key1","value7");

            myList.put("key1","value8");

            myList.put("key2","value9");

            myList.put("key2","value10");

            myList.put("key2","value11");

            myList.put("key2","value12");

            myList.put("key3","value13");

            myList.put("key3","value14");

            myList.put("key3","value15");

            myList.put("key3","value16");

Then get all keys from list

  Set myKeySet = myList.keySet();

  Object keys = myKeySet.toArray();

Now you have set of all key. then

    HashMap<String, String> listHashMap1 = new HashMap<>();

    HashMap<String, String> listHashMap2 = new HashMap<>();

    HashMap<String, String> listHashMap3 = new HashMap<>();

    HashMap<String, String> listHashMap4 = new HashMap<>();

Now add the value to every list

  for(int i=0;i<4;i++){

        List<String> keyval = (List)myList.get((String)keys[i]);

        listHashMap1.put((String)keys[i],keyval.get(0));

        listHashMap2.put((String)keys[i],keyval.get(1));

        listHashMap3.put((String)keys[i],keyval.get(2));

        listHashMap4.put((String)keys[i],keyval.get(3));

     }

Now you have set of four row list. This Multimap is using google guava.
So you need to implement guava in your gradle as below:
implementation 'com.google.guava:guava:26.0-jre'

From the code you supplied it seems that the source hashMap is of type Map<String, String>.

You could iterate over the entries of the map, and for each entry store the four values in different result containers. Since you indicated the result containers should be maps as well:

    Map<String, String> one = new HashMap<>();

    Map<String, String> two = new HashMap<>();

    Map<String, String> three = new HashMap<>();

    Map<String, String> four = new HashMap<>();



    hashMap.entrySet().forEach(entry -> {

        String values = entry.getValue();

        one.put(entry.getKey(), values[0]);

        two.put(entry.getKey(), values[1]);

        three.put(entry.getKey(), values[2]);

        four.put(entry.getKey(), values[3]);

    });

Note: assuming every key always has exactly four values.

I think this may work. I didn't get to test it but what it should do is there is an arraylist for each row and each element in the arraylist will contain "key value, " So for example:

Row 1 ArrayList: {"key value1", "key1 value5", "key2 value9", "key3 value13", "..."}
Please note that I didn't know what your hashMap would contain so the code below assumes that you have already initialized it and added in values.

ArrayList<String> row1 = new ArrayList<>();

ArrayList<String> row2 = new ArrayList<>();

ArrayList<String> row3 = new ArrayList<>();

ArrayList<String> row4 = new ArrayList<>();

for(int i = 1; i<= hashMap.size(); i++){

  if(i%4 == 1){

    int keynum = i - 1;

    keynum = keynum/4;

    String st = "key" + Integer.toString(keynum);

    //Assuming that the values are integers,

    row1.add(st +" " + hashMap.get(st));

  }else if(i%4 == 2){

    int keynum = i - 2;

    keynum = keynum/4;

    String st = "key" + Integer.toString(keynum);

    row2.add(st +" " + hashMap.get(st));

  }else if(i%4 == 3){

    int keynum = i - 3;

    keynum = keynum/4;

    String st = "key" + Integer.toString(keynum);

    row3.add(st +" " + hashMap.get(st));

  }else if(i%4 == 0){

    int keynum = i;

    keynum = keynum/4;

    String st = "key" + Integer.toString(keynum);

    row4.add(st +" " + hashMap.get(st));

  }

}

Now that you have the ArrayLists, all you have to do is pass them into an ArrayAdapter. If you need help with passing ArrayLists into your own custom listview adapter, you can read this tutorial here on how to do that.

I hope this helps.