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?
Solution: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(); }
Solution: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
Mapinterface - 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.
- If you want to modify the map while iterating, you'd need to use its
On different Map characteristics:
On enum
You may want to consider using an enum and EnumMap instead of Map<String,String>.
See also
Related questions
Solution:3
This with no warnings!
HashMap<String, String> meMap=new HashMap<String, String>(); meMap.put("Color1","Red"); meMap.put("Color2","Blue"); meMap.put("Color3","Green"); meMap.put("Color4","White"); for (Object o : meMap.keySet()) { Toast.makeText(getBaseContext(), meMap.get(o.toString()), Toast.LENGTH_SHORT).show(); }
Solution:4
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(); }
Solution:5
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(); }
Solution:6
this work for me:
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(); }
Solution:7
If you know Key, use this code
String value=meMap.get(key);
Solution:8
for (Object key : meMap.keySet()) { String value=(String)meMap.get(key); Toast.makeText(ctx, "Key: "+key+" Value: "+value, Toast.LENGTH_LONG).show(); }
Solution:9
Iterator iterator = meMap.keySet().iterator(); while(iterator.hasNext() ){ //get key String key=(String)iterator.next(); //toast value Toast.makeText(getBaseContext(),""+(String)meMap.get(key),Toast.LENGTH_SHORT).show(); } Note:If u also have question or solution just comment us below or mail us on toontricks1994@gmail.com
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