Access values of hashmap
Possible Duplicate:
How do I iterate over each Entry in a Map?
I am having a MAP, Map<String, Records> map = new HashMap<String, Records> ();
public class Records
{
String countryName;
long numberOfDays;
public String getCountryName() {
return countryName;
}
public void setCountryName(String countryName) {
this.countryName = countryName;
}
public long getNumberOfDays() {
return numberOfDays;
}
public void setNumberOfDays(long numberOfDays) {
this.numberOfDays = numberOfDays;
}
public Records(long days,String cName)
{
numberOfDays=days;
countryName=cName;
}
public Records()
{
this.countryName=countryName;
this.numberOfDays=numberOfDays;
}
I have implemented the methods for map, now please tell me How do I access all the values that are present in the hashmap. I need to show them on UI in android ?
You can use Map#entrySet
method, if you want to access the keys
and values
parallely from your HashMap
: -
Map<String, Records> map = new HashMap<String, Records> ();
//Populate HashMap
for(Map.Entry<String, Record> entry: map.entrySet()) {
System.out.println(entry.getKey() + " : " + entry.getValue());
}
Also, you can override toString
method in your Record
class, to get String Representation of your instances
when you print them in for-each
loop.
UPDATE : -
If you want to sort your Map
on the basis of key
in alphabetical order, you can convert your Map
to TreeMap
. It will automatically put entries sorted by keys: -
Map<String, Integer> treeMap = new TreeMap<String, Integer>(map);
for(Map.Entry<String, Integer> entry: treeMap.entrySet()) {
System.out.println(entry.getKey() + " : " + entry.getValue());
}
For more detailed explanation, see this post: - how to sort Map values by key in Java
你可以通过使用for循环来完成
Set keys = map.keySet(); // It will return you all the keys in Map in the form of the Set
for (Iterator i = keys.iterator(); i.hasNext();)
{
String key = (String) i.next();
Records value = (Records) map.get(key); // Here is an Individual Record in your HashMap
}
map.values()为您提供了一个包含HashMap中所有值的Collection
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