Android : how to create a Object using Reflection and pass constructor parameter?

Question

I'm trying a button using reflection in android, by the following code

 public String createView(String classFullName){
        try{
            Class clazz = Class.forName(classFullName);

            Object obj = clazz.newInstance(); // but I need to pass the Context using this;


        }
        catch(ClassNotFoundException ex){
            return null;
        }
    }

but the main problem, is how to pass Context ( which is this in my case ) to the Object since they all should be a View.

You'll need to get a reference to the constructor that takes the context and then call newInstance() on that constructor object. Take a look here: tutorials.jenkov.com/java-reflection/constructors.html — Gary Bak
– Gary Bak, Commented Apr 1, 2015 at 19:29

Mark Rotteveel · Accepted Answer · 2015-04-01 19:31:46Z

4

The method Class#newInstance() is just a convenience method to invoke a zero-arg constructor. If you want to invoke a constructor with arguments, you need to obtain the right Constructor instance through reflection using Class#getConstructor(Class...), and then call it using Constructor#newInstance(Object...).

So:

Class clazz = Class.forName(classFullName);
Constructor<?> constructor = clazz.getConstructor(Context.class);
Object obj = constructor.newInstance(this);

answered Apr 1, 2015 at 19:31

Mark Rotteveel

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