Calling Java method that uses hash map as a parameter

Question

I have a method in an android application:

public void changeImageView (HashMap<String,String> Detail)

I have been trying to call this method in the onCreate method in the same class.

I have tried:

changeImageView();

and

changeImageView(HashMap<String,String> Detail);

Both of which give me errors. The first gives me an error stating that the parameters are missing - understandable. But when I try the second version, I get an error saying "expression expected" with HashMap<String,String>.

I am probably missing something very obvious and have been unable to find anything online that can answer my question.

You need to provide a HashMap<String,String> object. You can create an empty hash map with new HashMap<String,String>() — Darth Android
– Darth Android, Commented Apr 8, 2016 at 17:13
Try changeImageView(someMap); where someMap is declared as HashMap<String, String> — codeMagic
– codeMagic, Commented Apr 8, 2016 at 17:13
And being nothing but sincere, you need to go through a basic Java tutorial and/or read a good book on learning Java before continuing Android programming or you will be miserable. — codeMagic
– codeMagic, Commented Apr 8, 2016 at 17:15
Brilliant, thank you so much for your comments! codeMagic: I am working through a few exercises from text books. I'm struggling slightly but getting there! Thank you for your response :) — pantha
– pantha, Commented Apr 8, 2016 at 17:20

Andrew · Accepted Answer · 2016-04-08 17:20:02Z

1

First, create an instance of HashMap<String, String>.

 Map<String, String> map = new HashMap<>();

After its filling or other operations on the map, pass it as a parameter to your method.

changeImageView(map);

I would suggest you reading about methods on Oracle Tutorials.

edited Apr 8, 2016 at 17:20

answered Apr 8, 2016 at 17:14

Andrew

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pantha Over a year ago

Thank you very much! I will accept your answer as soon as the 'time barrier' to accept lapses :)

Shubhi224 · Accepted Answer · 2016-04-08 17:26:58Z

1

HashMap is a collection class available in java.util package.

A method changeImageView() here has a definition which takes a HashMap object of type [Generic Type : Google it to know more about it].

You need to create a HashMap object :

Map<String,String> map=new HashMap<String,String>();

You can add values to the above hashmap as given below :

map.add("key1","value1");
map.add("key2","value3");

depending upon your requirements.

Now you can pass this map object to the changeImageView() method as given below:

changeImageView(map)

Seems like you are a newbie to Java and OOP , please refer any Java basic tutorials . This will help you to build up your basic concepts.

answered Apr 8, 2016 at 17:26

Shubhi224

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