How to print all key and values from HashMap in Android

Question

I am very new for Android development  and I am trying to use HashMap in Android sample project  Now  am doing sample project for learn android  I just store keys and values in HashMap  i want to show the keys and their values in EditView  I followed below code in my sample project  But  first key and value only printing in EditView       Map lt String  String gt  map   new HashMap lt String String gt        map put  iOS    100       map put  Android    101       map put  Java    102       map put   Net    103        Set keys   map keySet        for  Iterator i   keys iterator    i hasNext               String key    String  i next           String value    String  map get key          textview setText key           value          In EditView iOS   100 is only printing  I want to print all keys and their value in EditText  Can anyone please tell me where i am doing wrong  Thanks in advance

User · Answer

Java 8  map entrySet   forEach System out  println

User · Answer

you can use this code   for  Object variableName  mapName keySet         variableKey    variableName     n       variableValue    mapName get variableName      n     System out println variableKey   variableValue     this code will make sure that all the keys are stored in a variable and then printed

User · Answer

First  there are errors in your code  ie  you are missing a semicolon and a closing parenthesis in the for loop   Then  if you are trying to append values to the view  you should use textview appendText    instead of  setText     There s a similar question here  how to change text in Android TextView

User · Answer

It s because your TextView recieve new text on every iteration and previuos value thrown away  Concatenate strings by StringBuilder and set TextView value after loop  Also you can use this type of loop   for  Map Entry lt String  String gt  e   map entrySet            to get key     e getKey          and to get value     e getValue

User · Answer

For everyone who clicked on this to find out what the content of your HashMap is  the toString method  docs  actually works with most objects   note  a java array is not an object    So this woks perfectly fine for debugging purposes   System out println myMap toString       gt  gt  gt   key1 value1  key2 value2

User · Answer

With Java 8   map keySet   forEach key - gt  System out println key    - gt     map get key

User · Answer

You can do it easier with Gson   Log i TAG   SomeText      new Gson   toJson yourMap      The result will look like   I YOURTAG  SomeText    key1   value1   key2   value2

User · Answer

HashMap  lt Integer Integer gt  hm   new HashMap lt Integer Integer gt      Set lt Integer gt  keys   hm keySet       get all keys for Integer i  keys        System out println hm get i

User · Answer

public void dumpMe Map m    dumpMe m          private void dumpMe Map m  String padding         Set s   m keySet        java util Iterator ir   s iterator        while  ir hasNext                   String key    String  ir next            AttributeValue value    AttributeValue m get key           if  value    null               continue          if  value getM      null                        System out println  padding   key                        dumpMe  Map value  padding                      System out println padding                                     else if  value getS      null                      value getN      null                          System out println padding   key           value toString                       else                         System out println padding   key       UNKNOWN OBJECT      value toString                    You could also throw an exception here                          while      This code worked for me

User · Answer

for  Map Entry lt String String gt  entry   map entrySet        String key   entry getKey      String value   entry getValue         do stuff

User · Answer

String text          for  Iterator i   keys iterator    i hasNext                        String key    String  i next               String value    String  map get key              text  key           value                    textview setText text

User · Answer

This code is tested and working   public void dumpMe Map m    dumpMe m         private void dumpMe Map m  String padding      Set s   m keySet      java util Iterator ir   s iterator      while  ir hasNext          String key    String  ir next        Object value   m get key       if  value    null  continue      if  value instanceof Map          System out println  padding   key                  dumpMe  Map value  padding                System out println padding                             else if  value instanceof String                  value instanceof Integer                 value instanceof Double                  value instanceof Float                   value instanceof Long            System out println padding   key           value toString               else          System out println padding   key       UNKNOWN OBJECT      value toString              You could also throw an exception here                    while       dumpme   Charles

User · Answer

for  String entry   map keySet            String value   map get entry         System out print entry        value                  do stuff

User · Answer

Kotlin Answer  for   key  value  in map entries           do something with  key         so something with  value      You may find other solutions that include filterValues  Just keep in mind that retrieving a Key value using filterValues will include braces      val key   map filterValues  it   position  keys

[java] How to print all key and values from HashMap in Android?

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