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 color and want to display in "Toast". how do I display it?

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

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

---

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?