I have a hashtable filled with data, but I don't know the keys
How can I loop througth a HashTable keys in android?
I'm trying this, but it doesnt work:
Hashtable output=new Hashtable();
output.put("pos1","1");
output.put("pos2","2");
output.put("pos3","3");
ArrayList<String> mykeys=(ArrayList<String>)output.keys();
for (int i=0;i< mykeys.size();i++){
txt.append("\n"+mykeys.get(i));
}
Use enumeration to traverse over all the values in the table.
Probably this is what you would want to do:
Enumeration e = output.keys();
while (e.hasMoreElements()) {
Integer i = (Integer) e.nextElement();
txt.append("\n"+output.get(i));
}
You should use Map<String, String> instead of Hashtable, and the for-each notation for iteration whenever possible.
Map<String, String> output = new HashMap<String, String>();
output.put("pos1","1");
output.put("pos2","2");
output.put("pos3","3");
for (String key : output.keySet()) {
txt.append("\n" + key);
}
Your current code doesn't work because Hashtable.keys() returns an Enumeration, but you try to cast it to ArrayList which is not assignable from Enumeration.
Related
In arrayList I can add n number of values like the below code
RowOneCollection = new ArrayList<Button>((Arrays.asList(btn1,btn2,btn3,btn4)));
Similarly in hash map I am adding n number of vales like this
Map<String, String>map= new HashMap<String, String>();
map.put("bi","biology");
map.put("ma","maths");
like this I am adding n number of values.How I can add all the values in single line like the arraylist
You can put the data using For loop if you have 2 String arrays consisting of Keys and Values.
String[] keys = {"a","aa","aaa"}; //keep both array of same size.
String[] values = {"a1","aa2","aaa3"};
Map<String, String> map = new HashMap<String, String>();
for(int i = 0 ; i < keys.length; i++)
{
map.put(kays[i], values[i]);
}
Hope this helps.
You probably want to adjust how you are populating your HashMap as follows:
HashMap<String,xyz> hMap=new HashMap<String,xyz>();
for(int i=0;i<list.size();i++)
{
hMap.put("Data"+i, list);
}
Where xyz is the object, that you are working with. This approach allows you to take advantage of Java's Generics capability in its Collection objects such as HashMap.
I want to pass an array of the same element, but i want them to be passed as new fields. I want to do something like:
#POST("/api/userInfo/changeProfileData/")
void updateProfile(
#Field("userInfoProfile[languages][0]") String language1,
#Field("userInfoProfile[languages][1]") String language2,
Callback<BaseModel<StateModel>> callback);
But the problem is that i don't know the number of elements so i cannot do like above.
I tried to pass a list:
#Field("userInfoProfile[languages]") List<String> languages
but the value is not valid because i need fields with their index (userInfoProfile[languages][0]).
Use FieldMap to make field association more dynamic.
Update your interface to:
void updateProfile(
#FieldMap Map<String, String> languages,
Callback<BaseModel<StateModel>> callback);
Method that will build FieldMap out of your list
private Map<String, String> buildFieldMap(List<String> data){
Map<String, String> map = new HashMap<String, String>();
String fieldName = "userInfoProfile[languages][%d]"
for(int i = 0; i < data.size(); i++){
map.put(String.format(fieldName, i), data.get(i));
}
return map;
}
I've been looking for this for a while now, but couldn't find it anywhere in SO or in the docs.
I am using Gson to parse a json file, and suppose the file is:
{
"animal":"cat",
"paws":"4",
"eyes":"2"
}
Now, since all the fields are strings, I want to parse it as an array of strings, I want something like:
{"cat","4","2"}
And I would like to parse the JsonObject regardless of the name of its tags, and that's where the problem lies. I can garantee the json will contain only strings, but I have no clue of what the fields are going to be named.
Anyone ever faced this problem ? Any help is much appreciated, and any research direction also.
Edit
From the anwers, I managed to do it like this:
for (Map.Entry<String, JsonElement> entry : object.entrySet()) {
// do your stuff here
}
as explained in this answer
JSONObject has the keys() method that returns an Iterator<String>. Through the iterator you can retrieve the value associated with each key. Here the documentation
EDIT:
Since you are using GSON , you can retrieve the keys through the method entrySet()
You should use Iterator, which you can get by calling .keys() on your JSONObject. I think something like that should work (using org.json library):
String[] output = new String[jsonObject.length()];
Iterator iterator = jsonObject.keys();
int i = 0;
while (iterator.hasNext()){
output[i++] = jsonObject.optString((String) iterator.next());
}
EDIT Ok, in case of GSON it will be like this:
Set<Map.Entry<String, JsonElement>> set = jsonObject.entrySet();
String[] out = new String[set.size()];
int i = 0;
for (Map.Entry<String, JsonElement> x : set){
out[i++] = x.getValue().toString();
}
If you are using gson then simple solution is :
Type mapType = new TypeToken<Map<String, String>>(){}.getType();
Map<String, String> map = gson.fromJson(YOUR_JSON_STRING, mapType);
// get only values from map
Collection<String> values = map.values();
for (String string : values) {
// do your stuff here
}
result values collection contains
[cat, 4, 2]
JSONObject jsonObject = new JSONObject(parentJson.getJSONObject("objectname")
.toString());
Iterator<?> iter = jsonObject.keys();
while (iter.hasNext()) {
String key =(String) iter.next();
String value = jsonObject.getString(key);
}
I've created a JSON encode where you enter a HashTable (public Hashtable<?, ?> JSonDecode(String data) {... return objJS.toString(); } ) and get a string in JSON format. That is:
If I have a Hashtable with this (Hashtable in Hashtable):
Example Hashtable:
Hashtable<String, Object> exampleHT = new Hashtable<String, Object>();
exampleHT.put("Color", "Red");
exampleHT.put("OtherKey", "OtherValue");
exampleHT.put("OtherKey2", "OtherValue2");
Hashtable<String, Object> country = new Hashtable<String, Object>();
country.put("Spain", "Madrid");
country.put("France","Paris");
country.put("Italy", "Rome");
Hashtable<String, String> pokemon = new Hashtable<String, String>();
pokemon.put("Pikachu", "Electric");
pokemon.put("Charmander","Fire");
country.put("Pokemons", pokemon);
exampleHT.put("Countries", country);
I use my function(JSonEncode(exampleHT);) and I get this string:
{
"Color":"Red",
"Countries":{
"Spain":"Madrid",
"France":"Paris",
"Italy":"Rome",
"Pokemons":{
"Pikachu":"Electric",
"Charmander":"Fire"
}
},
"OtherKey":"OtherValue",
"OtherKey2":"OtherValue2"
}
It works perfectly! My problem is to create the reverse process, with JSonDecode.
Hashtable<?, ?> hashUnknown = JSonDecode(jsonStringExample);
public Hashtable<?, ?> JSonDecode(String data) {
// I do not know how to parse json in Hashtable, without indicating the tags manually.
}
I do not know how to parse json in Hashtable, without indicating the tags manually.
That is, without it:
JSONArray menuObject = new JSONArray (jObject.getString ("Color"));
JSONArray menuObject = new JSONArray (jObject.getString ("Countries"));
This should be dynamic without knowing json content without writing manually Color, Countries, ....
Any ideas or advice? Thanks,
You can get an Iterator object (java.util.Iterator) over the keys of your JSONObject (jObject)
So you can write something like this:
Iterator<String> it = jObject.keys();
String key = null;
Object value = null;
while (it.hasNext()) {
key = it.next();
value = jObject.get(key);
// Then test the instance of the value variable
// and perform some logic
}
I have a problem on arraylist and hashmap
As according to my requirement, I am storing the data into HashMap and after that I have created a List as List>.
HashMap<String,String> hashmap;
static List<HashMap<String,String>> hashmap_string;
And while retrieving the value from database and putting it on HashMap and ArrayList like:
contract_number=c.getString(c1);
Log.i("c1.getString,contract_number", contract_number);
String service_level=c.getString(c2);
hashmap=new HashMap<String, String>();
hashmap.put(contract_number, service_level);
hashmap_string.add(hashmap);
And now I want to retrieve the value as String,String
And when I am applying the code as:
for(int i=0;i<hashmap_string.size();i++)
{
Log.i("arraylist", ""+hashmap_string.get(i));
}
I am getting a single string value in the formet as
{Contract,ServiveValue}
but I want to split this into 2 string values...Also these values are redundant and if am using hashMap then it will not showing me the redundant value.
Please help me on this..
It seems you are missing something. When you execute hashmap_string.get(i), you will get the <HashMap<String,String>. So, This is the right value from code.
What you can do is :
HashMap<String, String> hashMap2 = hashmap_string.get(i);
String value = hashMap2.get("your_key");
Other way, you already have two splited string values. you can get that by using keySet() and values() methods over hashMap2 Object.
HashMap (and Maps in general) are used for multiple one-to-one mappings of keys and values. Are you sure you need that? Looking at your code it appears you're using the map as a "Pair" class. I would skip the list, and put everything in the same map, and then iterate over the pairs in the map:
// using tree map to have entries sorted on the key,
// rather than the key's hash value.
Map<String, String> data = new TreeMap<String, String>();
data.put("c1", "s1");
data.put("c2", "s2");
for (Map.Entry<String, String> entry : data.entrySet()) {
String contract = entry.getKey();
String level = entry.getValue();
Log.i("data", contract + " : " + level");
}
would output (assuming TreeSet):
c1 : s1
c2 : s2
Alternatively, create e.g. a ContractServiceLevel class that holds two strings (the contract number and the service level), and put instances of that class in your list.
EDIT:
public final class ContractServiceLevel {
public final String number;
public final String serviceLevel;
public ContractServiceLevel(String c, String s) {
number = c;
serviceLevel = s;
}
}
List<ContractServiceLevel> contracts = new ArrayList<ContractServiceLevel>();
contracts.add(new ContractServiceLevel("c1", "s1.1"));
contracts.add(new ContractServiceLevel("c1", "s1.2"));
contracts.add(new ContractServiceLevel("c2", "s2.1"));
for (ContractServiceLevel contract : contracts) {
Log.i("data", contract.number + ":" + contract.servicveLevel);
}
would output:
c1 : s1.1
c1 : s1.2
c2 : s2.1
String value = hashmap.get("contract");
u will be getting the value as ServiveValue