Android - Get value from HashMap

Question

I have tried to search on HashMap in Android, but getting problem:

Consider this example:

  HashMap<String, String> meMap=new HashMap<String, String>();
     meMap.put("Color1","Red");
     meMap.put("Color2","Blue");
     meMap.put("Color3","Green");
     meMap.put("Color4","White");

now i want to iterate it and get the value of each colour and want to display in "Toast". how do i display it ?

Any idea.

Answer 1

Iterator myVeryOwnIterator = meMap.keySet().iterator();
while(myVeryOwnIterator.hasNext()) {
    String key=(String)myVeryOwnIterator.next();
    String value=(String)meMap.get(key);
    Toast.makeText(ctx, "Key: "+key+" Value: "+value, Toast.LENGTH_LONG).show();
}

Answer 2

HashMap<String, String> meMap=new HashMap<String, String>();
meMap.put("Color1","Red");
meMap.put("Color2","Blue");
meMap.put("Color3","Green");
meMap.put("Color4","White");
Iterator iterator = meMap.keySet().iterator();
while( iterator. hasNext() ){
    Toast.makeText(getBaseContext(), meMap.get(iterator.next().toString()), 
    Toast.LENGTH_SHORT).show();
}

Answer 3

HashMap<String, String> meMap=new HashMap<String, String>();
     meMap.put("Color1","Red");
     meMap.put("Color2","Blue");
     meMap.put("Color3","Green");
     meMap.put("Color4","White");

     Iterator myVeryOwnIterator =  meMap.values().iterator();
     while(myVeryOwnIterator.hasNext()) {
         Toast.makeText(getBaseContext(), myVeryOwnIterator.next(), 
Toast.LENGTH_SHORT).show();
     }

Answer 4

Here's a simple example to demonstrate Map usage:

Map<String, String> map = new HashMap<String, String>();
map.put("Color1","Red");
map.put("Color2","Blue");
map.put("Color3","Green");
map.put("Color4","White");

System.out.println(map);
// {Color4=White, Color3=Green, Color1=Red, Color2=Blue}        

System.out.println(map.get("Color2")); // Blue

System.out.println(map.keySet());
// [Color4, Color3, Color1, Color2]

for (Map.Entry<String,String> entry : map.entrySet()) {
    System.out.printf("%s -> %s%n", entry.getKey(), entry.getValue());
}
// Color4 -> White
// Color3 -> Green
// Color1 -> Red
// Color2 -> Blue

Note that the entries are iterated in arbitrary order. If you need a specific order, then you may consider e.g. LinkedHashMap

See also

• Effective Java 2nd Edition, Item 52: Refer to objects by their interfaces
• Java Tutorials/Collections - The Map interface
• Java Language Guide/The for-each loop

Related questions

On iterating over entries:

• Iterate Over Map
• iterating over and removing from a map
  • If you want to modify the map while iterating, you'd need to use its Iterator.

On different Map characteristics:

• How to Maintain order of insertion using collections

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On enum

You may want to consider using an enum and EnumMap instead of Map<String,String>.

See also

• Java Language Guide/Enums

Related questions

• Enumerations: Why? When?